A method of brewing beer using low temperature hop locking

Abstract

The application discloses a kind of processes for brewing beer using hop locking, belongs to beer brewing technical field.The application uses commercial hop locking as raw material, through optimized thawing treatment, adding opportunity, and the thawed hop locking is used for beer brewing.The application directly uses commercial hop locking, without self-processing, simple operation;Through systematic thawing and adding process, the alpha-acid, beta-acid and volatile components of fresh hop are maximized to retain and release.Compared with the pellet hop process, the beer brewed by the application has less hop input (under the same moisture content), better foam retention, and typical "fresh hop" characteristics;Compared with the fresh hop process, the application can be produced throughout the year, and the quality is more stable.The application provides an efficient and economical solution for the industrial production of hop-flavored beer.

Description

Technical Field

[0001] This invention belongs to the field of beer brewing technology, specifically relating to a method for brewing beer using low-temperature preservation hops, wherein the preservation hops are subjected to rapid cooling, low-temperature crushing, nitrogen-filled packaging, and frozen preservation. Background Technology

[0002] Hops ( Humulus lupulus Hops (L.) are an indispensable ingredient in beer brewing, giving beer its unique bitterness, aroma, and preservative properties. Traditional forms of hop use mainly include compressed hop pellets, hop extract, and hop oil, all of which are processed from fresh hops through high-temperature roasting, crushing, and high-temperature pelleting. However, existing technologies have the following shortcomings: (1) Loss of chemical components of dried flowers / grain hops Hops contain α-acids, β-acids, and volatile aroma components, which are crucial to beer quality (Reference 4). During the drying, crushing, compression, and pelleting processes of hops, especially under high-temperature and aerobic conditions above 60-80℃, the chemical components in the hop glands rapidly degrade or volatilize, directly affecting hop quality. Studies have shown (Reference 4) that compared to traditional pelleted hops, frozen fresh hops (processed at low temperatures, frozen below -18℃) retain significantly higher levels of effective components (up to 90% or more). However, due to their high water content (approximately 75%) and susceptibility to spoilage, fresh hops are difficult to directly apply to conventional large-scale industrial production and seasonal storage at room temperature.

[0003] (2) Limitations of using fresh hops directly A few craft breweries have experimented with brewing "fresh hop beer" using fresh hops (undried hops with a water content of approximately 75%), typically concentrated during the hop harvest season in September and October. However, fresh hops begin to oxidize and deteriorate within hours of harvesting at room temperature, and even under normal refrigeration (0–4°C), they usually need to be used within 24–48 hours, otherwise the flavor will deteriorate significantly. Therefore, fresh hop beer is severely limited by the hop season, with only a 4–6 week brewing window each year, making year-round production impossible.

[0004] (3) Shortcomings of existing freezing technology Existing literature reports on freezing hops for preservation, but most of these methods treat frozen hops as an intermediate product, requiring subsequent processing steps such as drying, crushing, and granulation. These high-temperature, aerobic processes lead to significant loss of flavor compounds, thus freezing does not fundamentally solve the flavor preservation problem. Some processes have attempted to use frozen, intact hops directly in brewing, but this presents the following issues: Low extraction efficiency: The utilization rate of α-acids and volatile aromas is significantly lower than that after crushing and feeding. High storage costs: The volume occupied by a unit weight of whole hops is about 5-10 times that of crushed hops, resulting in serious waste of cold storage space; Inconvenient to operate: Whole flowers are prone to clogging pipes and unevenly dispersed, making them difficult to adapt to automated brewing lines; Lack of systematic process optimization: There are no mature solutions for thawing rate, addition timing (boiling / swirl / dry addition), etc., which results in the ineffective utilization of bitter and aroma components.

[0005] In summary, the existing technology has the following problems: 1. Dried flowers / granulated hops: The high temperature and oxidation during the drying, crushing, and granulation processes result in a significant loss of bitter substances and aroma components; 2. Fresh hops can be used directly: Their high water content (about 75%) makes them extremely prone to rotting and spoilage. The window for use is limited to 4–6 weeks during the harvest season, and there is a high risk of microbial contamination. 3. Current applications of frozen hops: Most are used only as intermediate products, and subsequent processing still results in flavor loss; a few methods use whole frozen hops directly, but these have low utilization rates, high storage costs (the volume is 5-10 times that of crushed hops), inconvenient operation, and lack of systematic optimization of thawing rate and addition timing.

[0006] Therefore, developing a brewing process using frozen fresh hops that can fully preserve the bitter and aromatic components of fresh hops while enabling year-round production has significant application value. Summary of the Invention

[0007] This invention aims to overcome the shortcomings of existing technologies and provide a method for brewing beer using frozen fresh hops. This method uses frozen fresh hops as raw material, and through optimized freezing and thawing processes and precise timing of addition, effectively preserves and releases α-acids, β-acids, and volatile aroma components in the fresh hops. The operating conditions are controllable, batch-to-batch quality is stable, and it is not limited by the hop season, enabling year-round production.

[0008] The core concept of this invention is to use low-temperature fresh-locking hops as the direct brewing raw material, and through systematically optimized thawing temperature and sample state and precise control of the timing of addition, to maximize the retention and synergistic release of bitter substances and aroma components in fresh hops while avoiding the heat and oxygen loss in traditional processing.

[0009] The difference from existing technologies is: Unlike dried hops / granulated hops: it eliminates the high-temperature and aerobic processes of drying, crushing, and granulation, resulting in a significantly higher retention rate of flavor compounds; Unlike fresh hops used directly: it is frozen at -18℃ or below for long-term storage, ensuring safe and controllable microbial safety, and extending the brewing window from 4–6 weeks to all year round; Unlike the simple application of frozen hops in the past, this method clearly defines the synergistic process conditions of the thawing rate range and addition stage (such as the end of boiling / whirling sedimentation / dry hopping), so as to achieve stable and repeatable high-efficiency utilization of α-acid isomerization and aroma release.

[0010] The beer brewing process using low-temperature hop preservation hops described in this invention includes the following steps: Step 1: Preparation of frozen fresh hops (harvesting → impurity removal → pre-cooling → crushing → packaging → frozen storage) 1.1 Harvesting and processing: Fresh hops grown in Xinjiang are harvested during the hop harvest season (early to late September). After harvesting, the hops are transported to the processing workshop in the dark within one hour, where branches, leaves and impurities are removed using a magnetic separator.

[0011] 1.2 Pre-cooling: The cleaned fresh hops are transported to a low-temperature freezing tunnel (1.05 m × 16.0 m). The internal cold air temperature is -18℃, which can be -18 to -25℃, preferably -18 to -20℃. After passing through the low-temperature tunnel, the fresh hops are rapidly cooled from room temperature of 25℃ (which can be 20-30℃, preferably 25-30℃) to 4℃ (which can be 2-5℃, preferably 3-4℃), keeping the plants in the freshest state with the lowest degree of oxidation. 1.3 Low-temperature grinding: The pre-cooled hops are immediately ground in a low-temperature grinding workshop at -18°C (which can be -18 to -25°C, preferably -18 to -20°C) or below, using a low-temperature grinder to crush them to a particle size of 0.2–0.5 cm, preferably -0.3–0.4 cm; this process allows the hops ground at 4°C (which can be 3-5°C) to be directly cooled to -18°C; 1.4 Packaging and Nitrogen Vacuum Filling: Place light-proof aluminum foil bags of the same size as the mold into the mold (internal dimensions 40cm × 40cm × 5cm (thickness can be 3-10cm, preferably 4-6cm)). Fill each bag with 5.0 kg (can be 3.0–10.0kg, preferably 4.0–6.0 kg) of hop powder, press and shape, and perform two vacuum filling and nitrogen filling processes: First, evacuate to a vacuum level below -0.06 MPa (gauge pressure) (can be below -0.05 MPa, preferably below 0.04 MPa), and purge with high-purity nitrogen gas (volume purity ≥ 99.5%) to atmospheric pressure to initially replace the air inside the bag; Second, evacuate to a vacuum level below -0.08 MPa (gauge pressure) (can be below -0.06 MPa, preferably below 0.05 MPa). After refilling with nitrogen to atmospheric pressure (below MPa), the aluminum foil bag is sealed to ensure that the residual oxygen volume concentration inside the bag is <0.5% (can be <0.4%, preferably below 0.3%), effectively isolating oxygen and moisture, inhibiting the oxidative degradation of α-acids and β-acids in hops and the volatilization loss of aroma components, and extending the shelf life of hop powder.

[0012] 1.5 Frozen Storage: Transfer the packaged hop chunks to a cold storage facility at -18°C or below (ideally -18 to -25°C, preferably -18 to -20°C) and lay them flat for later use. The total time from harvesting to completion of frozen storage should be controlled within 3 hours; Thawing process for fresh-locking hops Remove the frozen crushed hops along with the aluminum foil bag and thaw them at room temperature (20–25°C) in the dark until the temperature in the middle of the hops reaches 2–5°C, preferably 3–4°C, for 4.5–5.5 hours.

[0013] For boiling / whirlpool sedimentation addition: Thaw until there are no hard lumps in the center of the hop block, and the internal hop powder is 4°C, then add the hops immediately after opening. This method can minimize the loss of hop aroma and the degradation of α- and β-acids due to temperature rise, restoring the hops to near their freshest state of 4°C (or 3–5°C).

[0014] To preserve the fresh, pure, and original flavor of hops to the greatest extent possible, it is recommended to thaw the hop blocks until there are no hard lumps in the center and the internal powder temperature reaches precisely 4°C (3–5°C) before opening the packaging and immediately adding the hops. This method minimizes the loss of hop aroma and the degradation of α- and β-acids caused by increased temperature, ensuring that the hops are "awakened" at their optimal condition (4°C), restoring their freshest and most expressive original flavor.

[0015] Step 2: Wort Preparation Gelatinizing pot: Take 3200–4000 kg of rice (crushed to a particle size of ≤1.8 mm), 8.2–10.25 KL of water, adjust the temperature of the slurry water to 60±1℃, and then raise the temperature at a rate of 0.5–1℃ per minute. After raising the temperature to 70±1℃, keep it at that temperature for 8–12 minutes. After raising the temperature to 93±2℃, keep it at that temperature for 30–40 minutes.

[0016] Saccharification pot: Take 5450-6800 kg of brewing malt and saccharify it at a material-to-water ratio of 1:3-1:4. Add the malt at 50±2℃. After adjusting the malt mash, allow the protein to decompose for 45±5 minutes. Add the gelatinized product and mix with the mash. Saccharify at 64±2℃ for 40±5 minutes. Increase the temperature to 72±1℃ and saccharify for approximately 30±5 minutes. Continue iodine testing at 76-78℃ (based on the iodine solution test result, until no blue color reaction occurs). After mashing, the mixture is filtered to remove solids. The remaining wort is then boiled for 60-70 minutes. Fresh hops are added after 5±1 minutes of initial boiling. The boiling intensity (the percentage of water evaporated per hour during boiling, equivalent to the volume of the mixed wort) is controlled at 8-9%. The hot wort is then pumped at high speed tangentially along the tank wall. The liquid swirls along the tank wall, generating centrifugal force. Heavy materials are thrown against the tank wall by this centrifugal force and slide down to the bottom. The wort is clear and has a low density, remaining in the upper and middle layers. The bottom of the tank is an inverted cone shape, where hop mud and other substances continuously gather to form a compact, hot-coagulated cone. The clear wort flows out from the upper and middle parts of the side wall and is sent to the cooling tank. A second round of fresh hops is added to the whirlpool settling tank, with a desired wort bitterness of 19–24 BU. After boiling, the desired concentration is achieved, with a desired pH of 5.2–5.6. The wort is clarified (whirlpool settling time) for 20 ± 5 minutes and then cooled to 9 ± 2°C to enter the fermentation stage.

[0017] Step 3: Adding hops to lock in freshness Add the thawed frozen fresh hops from step 1 to the beer brewing process, at the following times: Implementation method – Segmented addition (complex flavor): Adding it at the initial stage of boiling allows the α-acids of hops to be fully isomerized by high-temperature and long-term boiling, giving the beer a basic bitterness and balancing the sweetness of the malt; at the same time, it sterilizes, inhibits miscellaneous bacteria, and improves the preservation stability of the wort.

[0018] It is added during the swirling sedimentation stage, when the wort has stopped boiling violently and the temperature has gradually decreased, with no large amount of steam volatilization. The hop essential oils and terpenoid aromatic substances are almost not destroyed or lost, mainly to give the beer a distinctive fresh floral, fruity and herbal aroma, making up for the aromas lost due to the high temperature of boiling.

[0019] Boiling stage: 5 minutes for initial boiling (can be 4–6 minutes), amount added: 0.08% (w / v) of wort volume, equivalent to 80g / 100L wort (can be 0.07–0.09%). Whirling sedimentation stage: Amount added: 0.04% (w / v) of wort volume (can be 0.03%–0.05%). Fermentation: Inoculate with Lagerstroemia indica (inoculation amount 1.2–2.5 × 10⁻⁶) 5 The fermentation tank was filled with yeast (wort volume / mL) at a temperature controlled at 10±0.2℃. When the sugar content dropped to 3.8–4.0 BX, the tank was sealed (Bryce). The tank pressure was controlled at 0.08 MPa (±0.01 MPa). After sealing, the temperature was raised to 12±0.2℃ for diacetyl reduction. Diacetyl levels were measured starting on the 7th day after sealing. When the diacetyl content dropped below 0.06 mg / L, the temperature was lowered to -0.5±0.5℃ for storage. The storage pressure was the natural pressure of the fermentation tank after cooling and dissipation of yeast. Step 4: Filtration and Filling After diatomaceous earth filtration, membrane filtration, filling, and pasteurization.

[0020] Beneficial effects Compared with the prior art, the present invention has the following beneficial effects: 1. High retention rate of bitter components, reduced feed amount, and lower raw material costs. The frozen fresh hops used in this invention completely avoid high-temperature drying above 60-80℃ and aerobic granulation environment during processing, effectively inhibiting the thermal degradation and oxidative loss of α-acids, β-acids and volatile terpenoids (including myrcene, caryophyllene, humulene, etc.).

[0021] High retention rate: Experiments show (Reference 4) that the α-acid retention rate of the fresh hops described in this invention can reach over 90%, and the retention rates of β-acids and major volatile components are also significantly higher than those of traditional processing methods. In contrast, during the drying and pelleting process of traditional pellet hops, the loss of α-acids is 20%–30%, and the total loss of volatile aroma components exceeds 50%.

[0022] Reduced feed amount: Under the condition of achieving the same beer bitterness value (IBU), the amount of frozen fresh hops described in this invention is reduced by 15%–25% compared with traditional dried hops or pellet hops, thereby directly reducing the hop raw material cost per unit product.

[0023] Superior bitterness quality: The α-acids retained in this invention undergo more complete isomerization during boiling, increasing the proportion of iso-α-acids generated, resulting in a higher bitterness value and purer bitterness, and eliminating the after-bitterness caused by oxidation in traditional pellet hops.

[0024] 2. Optimized thawing process to preserve flavor to the maximum extent. For frozen pulverized hop blocks with a thickness of 5 cm and a weight of 5.0 kg, this invention proposes a thawing process that matches the addition stage.

[0025] Rapid thawing: Thaw at room temperature (20–25℃) in the dark for 4–6 hours, until no visible ice crystals are visible on the surface of the hops, but a small amount of ice crystals remain in the center. This method effectively avoids three major problems caused by prolonged thawing: microbial growth, volatilization of volatile aroma components, and oxidation of flavor substances.

[0026] Staged thawing control: Depending on the stage of addition (boiling, swirling sedimentation), the corresponding degree of thawing (partial softening or complete softening) is matched to achieve the synergistic release of bitter substances and aroma components, overcoming the technical defects of flavor loss caused by a single thawing method.

[0027] 3. Easy to operate; commercially available products can be used directly. The frozen fresh hops used in this invention are commercial products that have undergone the entire processing chain, including harvesting, impurity removal, pre-cooling, low-temperature crushing, double nitrogen-filled vacuum packaging, and freezing at -18°C or below.

[0028] No pretreatment required: Breweries do not need to pick, wash, or freeze the flowers themselves.

[0029] High equipment adaptability: Breweries only need to have conventional cold storage or refrigeration equipment below -18℃ to realize storage and use, without the need to purchase special thawing equipment. Existing equipment such as boiling pots, vortex sedimentation tanks, and fermentation tanks can be directly adapted.

[0030] Simplified operation: After thawing, the bag can be opened directly for feeding, without the need for additional crushing, weighing or other steps, which significantly reduces human error.

[0031] 4. Not limited by the flowering season, enabling year-round production. Long-term stable storage: Under conditions of -18℃ and vacuum packaging in aluminum foil bags (residual oxygen <0.5%), fresh hops can be stably stored for 24–36 months with almost no quality degradation.

[0032] Balanced production throughout the year: Breweries can centrally purchase frozen products during the fresh hop harvest season in September and October each year, achieving balanced use throughout the year and completely solving the industry pain point of only 4-6 weeks of brewing window for new beer and fresh hops.

[0033] Improved equipment utilization: Compared with the idle equipment caused by the need for concentrated brewing of fresh hops, this invention can achieve balanced production throughout the year, significantly improve equipment utilization, and further reduce fixed costs.

[0034] 5. Stable quality and high microbial safety. Controllable processing: Fresh-locking hops undergo magnetic separation for impurity removal, low-temperature pulverization, and double nitrogen-filled vacuum packaging during processing, ensuring that initial microbial indicators are controllable.

[0035] Freezing inhibits microorganisms: Long-term storage at -18°C effectively inhibits microbial growth. Compared to fresh hops, which begin to spoil within hours at room temperature, this invention significantly reduces the risk of microbial contamination.

[0036] Thorough sterilization during boiling: When fresh-locking hops are added during the boiling stage (≥95℃, 30–60 minutes), thorough sterilization can be achieved; when added during the swirling sedimentation stage (85–95℃, 15–30 minutes), sufficient safety can be maintained while imparting a distinctive fresh floral, fruity, and herbal aroma to the beer.

[0037] 6. Overall improvement in sensory quality Bitterness: The beer of this invention has a higher bitterness value and a purer bitterness. It does not have the oxidized bitterness or rough bitterness commonly found in traditional pellet hops. The balance between bitterness and aroma is better, and it has typical fresh hop characteristics.

[0038] Taste: The beer has a richer and more complex flavor profile. The polyphenols and glycerol retained in the fresh hops enhance the roundness and complexity of the beer, resulting in a milder, less sharp bitterness and a clean finish.

[0039] Aroma: The aroma is fresh and rich, with obvious characteristics of fresh hop aroma such as myrcene (citrus and pine) and caryophyllene (spicy and woody), without the "mature" or "aged" flavor that comes from long-term storage of hop grains.

[0040] Color: Due to the avoidance of high-temperature oxidation, the beer has a clearer and more stable color, with no oxidative browning. Pale beer can maintain a bright golden yellow color.

[0041] Foam: The polyphenols in hops combine with wort proteins, significantly improving the fineness, whiteness, and persistence of the foam. According to measurements (Reference 4), the foam retention of beer brewed using this invention can reach 180–240 seconds, which meets and exceeds the national superior standard (≥180 seconds) of GT / T4927-2025 (Reference 1).

[0042] 7. Overall costs are controllable. Reduced raw material costs: The amount of raw materials used is reduced by 15%–25%, directly reducing the cost of purchasing hops.

[0043] Stable procurement costs: Fresh-locked hops can be purchased in bulk and used throughout the year, avoiding the risk of raw material price fluctuations due to the flowering season (fresh flowers are expensive and supply is unstable during the flowering season).

[0044] Operational cost optimization: Balanced production improves equipment utilization and reduces additional costs (such as overtime, temporary warehousing, etc.) caused by seasonal shutdowns and rush production.

[0045] Overall assessment: Compared with using fresh hops, this invention can reduce overall production costs by 20%–30% (including raw materials, storage, labor, and equipment depreciation); compared with using traditional pellet hops, although the unit price of raw materials may be slightly higher, it still has significant economic competitiveness due to the reduced amount of raw materials and the quality premium. Attached Figure Description

[0046] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0047] Example 1 (1) Preparation of fresh-locking hops Fresh Marco Polo hops grown in Xinjiang are harvested in mid-September. Within one hour of harvesting, they are transported to the processing workshop in the dark. After being de-impregnated by a magnetic separator, the hops are rapidly cooled from room temperature (25°C) to 4°C using a low-temperature tunnel (1.05 m × 16.0 m) with cold air at -18°C. The hops are then immediately transferred to the pulverizing workshop and pulverized at -18°C to a particle size of 0.2–0.5 cm. This process allows the hops, which are pulverized at 4°C (or 3–5°C), to be directly cooled to -18°C. 5.0 kg of the product is packed into aluminum foil bags with an inner cavity size of 40 cm × 40 cm × 5 cm, placed in a mold (inner cavity size 40 cm × 40 cm × 5 cm). The bags undergo two vacuuming and nitrogen-filling processes: first, vacuuming to -0.06 MPa (gauge pressure), then filling with high-purity nitrogen (volume purity ≥ 99.5%) to atmospheric pressure; second, vacuuming to -0.08 MPa (gauge pressure), then filling with nitrogen again to atmospheric pressure, with nitrogen volume purity ≥ 99.5%. This ensures the residual oxygen volume concentration inside the bag is <0.5%. After sealing the aluminum foil bags neatly, they are stored in a -18℃ cold storage for later use. The time from harvesting to storage should be controlled within 3 hours.

[0048] (2) Thawing process for fresh hops to lock in freshness Take the fresh-locking crushed hop block (5.0 kg, 40 cm × 40 cm × 5 cm) prepared in step (1), along with the aluminum foil bag, and place it at room temperature of 20–25℃ in the dark for 5 hours to thaw until there are no visible ice crystals on the surface of the hops and a small amount of ice is still formed in the center. The temperature in the middle of the hop block is 4℃.

[0049] (3) Brewing beer using fresh-locking hops (12.5% ​​fresh 100% beer) (1) Raw material preparation Take 60 kg of fresh hops (variety: Marco Polo, frozen at -18℃ for 6 months), thaw them according to step (2) and use them immediately.

[0050] (2) Preparation of wort Take 3200 kg of rice (crushed to a particle size of ≤1.8 mm) and 8.2 KL of water for gelatinization; adjust the water temperature to 60℃, then raise the temperature at a rate of 0.6℃ per minute, hold at 70℃ for 10 minutes, raise the temperature to 93℃ and hold for 30 minutes to obtain the gelatinized product.

[0051] Take 5450 kg of malt (barley that has undergone selection, cleaning, soaking, germination, drying, roasting, root removal, and screening to become brewing malt (this step is completed by the malt supplier)) and saccharify it at a malt-to-water ratio of 1:4. Saccharification procedure: 50℃ protein rest for 45 minutes (protein rest is a crucial temperature control step in beer brewing saccharification; its core purpose is to utilize the malt's own proteases to break down large protein molecules into medium-molecular-weight peptides and small-molecular-weight amino acids, which are more beneficial for fermentation; because the process involves mostly static standing with little stirring, it is called "rest"). Add the gelatinized product and saccharify at 64℃ for 40 minutes, then at 72℃ for 5 minutes. Finally, perform an iodine test at 78℃ until no blue color reaction occurs (iodine test is a rapid detection method used in beer brewing saccharification to determine whether saccharification is complete. It utilizes the principle that iodine solution changes color upon contact with starch; by observing the color change after mixing wort and iodine, it confirms whether the starch has been completely converted into sugar). After mashing, the mixture is filtered to remove solids. The remaining wort (generally, the unfiltered, paste-like mixture before boiling is called "mash"; the liquid after filtration, without added hops or concentration, is generally called "original wort". After boiling, the liquid has solidified and is called "wort") is boiled for 60 minutes at a boiling intensity of 8.5%.

[0052] (3) Adding fresh hops to lock in freshness Five minutes into the initial boiling phase of the wort, hops thawed to 4°C are added (0.08% wort volume, w / v, equivalent to 80g / 100L wort, approximately 50KL). After boiling for 60 minutes, the wort enters the vortex settling stage (the high-temperature wort after boiling is pumped in at high speed along the tangential direction of the tank wall, and the liquid swirls around the tank wall, generating centrifugal force; heavy substances are thrown towards the tank wall by centrifugal force and slide down to the bottom center; the clear wort has a lower density and remains in the upper middle layer; the bottom of the tank is an inverted cone shape, and hop mud and other substances continuously gather to the very center, forming a compact hot solidified cone; the clear wort flows out from the upper middle part of the side wall and is sent to the cooling zone). Hops thawed to 4°C are added (0.04% wort volume, w / v, equivalent to 40g / 100L wort, approximately 50KL). After vortex settling for 20 minutes, the wort is cooled to 9°C.

[0053] (4) Fermentation Inoculate with Lagerstroemia indica (inoculation amount 1.5 × 10⁻⁶) 5 The primary fermentation temperature is controlled at 10±0.2℃. When the sugar content drops to 3.9°BX (the unfiltered mixed paste before boiling is called "saccharified mash"; the filtered liquid without added hops and without concentration and setting is generally called "original wort". After boiling, the liquid has set and is called "wort"), the tank is sealed and the tank pressure is controlled at 0.08 MPa. During sealing, the temperature is raised to 12℃ to reduce diacetyl. Diacetyl is measured starting on the 7th day after sealing (diacetyl is a key flavor compound in beer fermentation; when yeast metabolizes and synthesizes amino acids, it produces the intermediate α-acetolactic acid; this substance seeps out of the yeast cells and undergoes oxidation upon contact with oxygen; ultimately transforming into diacetyl; in the later stages of fermentation, the yeast reduces diacetyl to a tasteless substance, completing the beer maturation). Specifically: 1. Sampling: Quickly isolate from air to avoid oxidation interference; 2. Distillation: Heat the sample and distill, collect the distillate, and dilute to a fixed volume to extract the diacetyl component; 3. Colorimetric analysis: Add o-phenylenediamine reagent, and react in the dark to form a colored complex; 4. Absorbance measurement: Use a spectrophotometer to read the absorbance value at a fixed wavelength; (detailed steps are shown in GB / T4928-2026)). The diacetyl concentration (determined according to GB / T 4928-2026) is measured when it reaches 0.06 mg / L. When the temperature drops to -0.5±0.5℃, the wine is stored at the same pressure as the natural pressure after the yeast has been discharged from the fermentation tank. (5) Filtering and filling The product is filtered through diatomaceous earth, then through a 0.65-micron membrane, filled, and pasteurized.

[0054] (6) Evaluation of results The resulting 12.5% ​​Fresh 100 beer has a light yellow and clear color, a mellow and elegant hop aroma (IBU≈12), and a pure and dry taste.

[0055] 1. It has a refreshing and smooth taste, is gentle and non-irritating on the palate, has a moderate burn, and provides a comfortable drinking experience; 2. The flavor is clean and pure, with a prominent malt aroma and a mild and harmonious hop bitterness, free of off-flavors and raw, grassy taste; 3. The wine is clear and bright, with a beautiful and clear color, and the foam is dense and long-lasting, providing a good visual experience; 4. It has a refreshing aftertaste and a clean finish, leaving no heavy or greasy feeling after drinking. It is excellent at quenching thirst and cutting through greasiness. 5. The flavor profile is well-balanced, with a harmonious blend of malty sweetness, hoppy bitterness, and beer aroma, resulting in an overall balanced taste. Beer aroma scoring criteria using different hops

[0056] Effect Comparison Table

[0057] Comparison of proportions Comparative Example 1 (Pellet Hops): Commercially available T90 hop pellets (dried at 60℃ and granulated at 45℃) were used to replace the fresh-locking hops, and the remaining process and conditions were the same as in Example 1. In step (3), during the addition of fresh-locking hops, the thawed fresh-locking hops were replaced with T90 hop pellets, and the addition amount was calculated according to the same IBU target value (12), and added in two stages: In the first 5 minutes of boiling: add T90 hop pellets at a rate of 0.10% (w / v) of the wort volume, equivalent to 100g / 100L of wort (based on α-acid content: T90 hop pellets contain approximately 11.0% α-acid, and freshness-locking hops contain approximately 12.5% ​​α-acid; with equal amounts of α-acid added, the conversion factor is 1.14). Whirlpool settling stage: Add T90 hop pellets at a rate of 0.05% (w / v) of the wort volume, equivalent to 50g / 100L wort (calculated proportionally). After boiling for 60 minutes, the wort enters the whirlpool sedimentation stage. After adding hop pellets, it is whirlpooled for 20 minutes, and then cooled to 9°C. The remaining process and conditions are the same as in Example 1.

[0058] The beer brewed using the above process was compared with that in Example 1, and the results are as follows: (1) Aroma characteristics: Sensory evaluation (out of 10, n=10) The aroma intensity score was 6.0 and the aroma naturalness / freshness score was 5.5, which were significantly lower than the 7.5 and 7.0 scores of Example 1, respectively. The aroma characteristics were mainly hay and resin, lacking the fresh floral and fruity aroma of Example 1. The aroma decayed rapidly after shaking and had no freshness.

[0059] (2) Turbidity of the wine: The EBC turbidity was 0.52, which was higher than 0.20 in Example 1, indicating that the ultrafine powder contained in the hop particles was difficult to settle fully during the swirling sedimentation stage, affecting the clarity of the wine.

[0060] (3) Microbial stability: After being stored at room temperature in a sealed container for 3 months, the total number of colonies was <10 CFU / mL, which met the national standard requirements, but was higher than <1 CFU / mL in Example 1.

[0061] (4) Foam retention: The foam retention time was 165 seconds, which is lower than the 180-240 seconds range of Example 1. The foam fineness and cup adhesion were not as good as Example 1.

[0062] (5) Overall flavor score: The sensory evaluation was conducted according to GB / T 4928-2026 (out of 100). The overall score was 80.4 points, which was lower than 91.6 points in Example 1. The main deductions were for aroma (particle hops 26.3 points vs. Example 1 32.1 points) and taste (particle hops 19.4 points vs. Example 1 22.7 points).

[0063] Conclusion: The beer obtained in Comparative Example 1 had a bland and thin aroma, lacked the characteristic floral and fruity aromas of fresh hops, and had poor foam persistence. Its overall sensory quality was significantly inferior to that of Example 1. This indicates that traditional pelleted hops, due to high-temperature drying and pelleting, have lost a large amount of volatile aroma components and polyphenols, and therefore cannot achieve the fresh flavor quality of hops that retain freshness.

[0064] Comparative Example 2 (Direct Inoculation with Fresh Hops): The process and conditions were the same as in Example 1, except that fresh hops harvested during the harvest season (fresh Marco Polo hops grown in Xinjiang were harvested in mid-September) were used instead of fresh-locked hops. Fresh hops (75% water content) were harvested during the harvest season and put into the boiling pot and vortex sedimentation tank within 2 hours after harvesting. No freezing or thawing treatment was performed. The remaining process and conditions were the same as in Example 1.

[0065] Usage results: (1) Aroma presentation: The aroma intensity score was 9.0 points and the aroma naturalness / freshness score was 8.8 points, which was the highest among the three groups. The fresh hops presented an explosive floral and fruity aroma that ran through the entire body of the beer from beginning to end, making it highly recognizable.

[0066] (2) Turbidity of the beer: The EBC turbidity was 1.28, which was significantly higher than that of Example 1 (0.20) and Comparative Example 1 (0.52). The fresh hops had a high water content (75%) and were not crushed and shaped. After feeding, a large amount of plant tissue debris, chlorophyll and protein complexes entered the wort system, far exceeding the carrying capacity of the vortex sedimentation and filtration stages, resulting in turbidity of the beer.

[0067] (3) Microbial stability: After being stored at room temperature in a sealed container for 3 months, the total bacterial count reached 3.2 × 10⁻⁶. 3 The concentration of CFU / mL far exceeds the national standard limit. Fresh hops have a high water content, and the wild yeasts, bacteria, and other microorganisms on their surface continue to multiply in unpasteurized beer, severely limiting its shelf life.

[0068] (4) Production seasonality: Production is limited to the harvest season in September–October each year, with a brewing window of only 4–6 weeks, making it impossible to achieve balanced production throughout the year.

[0069] (5) Raw material cost: The total cost of hops consumption per ton of finished beer is RMB 200 / ton of beer (including seasonal premium), which is significantly higher than RMB 25 / ton of beer in Example 1 and RMB 19 / ton of beer in Comparative Example 1.

[0070] (6) Flavor defects: In the sensory evaluation, some tasters reported that the fresh hops had a raw and grassy flavor (because they had not undergone any processing, some grassy precursors were not converted). Although the aroma intensity was the highest, the purity was slightly inferior to that of Example 1.

[0071] Conclusion: Comparative Example 2 yielded the beer with the best aroma freshness, but suffered from four fatal flaws: severe beer turbidity, poor microbial stability, production limited by flowering season, and high raw material costs, making it unfeasible for year-round industrial production. In contrast, Example 1 achieved a comprehensive advantage while maintaining high aroma quality (7.5 points), clear beer body (EBC 0.20), microbial safety (<1 CFU / mL), year-round production, and controllable costs (25 yuan / ton of beer).

[0072] Comparative Example 3 The process and conditions are the same as in Example 1, except that: In step (1) of the preparation of fresh hops, fresh Marco Polo hops grown in Xinjiang are harvested in mid-September. Within one hour of harvesting, they are transported to the processing workshop in the dark. After being removed by a magnetic separator, they are crushed at room temperature with a particle size of 0.2–0.5 cm. Then, they are rapidly cooled in a low-temperature tunnel (1.05 m × 16.0 m) with an internal cold air temperature of -18°C to reduce the temperature of the hops from room temperature of 25°C (which can be 20-30°C) to -18°C.

[0073] Usage results: (1) Grinding effect: When grinding at room temperature (25℃), the hops have a water content of about 75%, and the hops are soft and tough. During the shearing process, a large amount of cell sap overflows, resulting in uneven grinding and powder clumping. According to the sieving test, the proportion of particles with a diameter ≤0.5 cm is only 58.3%, while the proportion of large particles >0.5 cm and irregular lumps is 41.7% (≥92% in Example 1), and obvious traces of juice seepage can be seen on the powder surface.

[0074] (2) Cell disruption rate: The cell disruption rate was 18.6% when counted under a microscope (88.6% in Example 1). When pulverized at room temperature, the hop cells were squeezed and torn rather than fractured in a non-brittle state. Most of the hop glands remained intact but were damaged and deformed, which hindered the dissolution of active ingredients during subsequent extraction.

[0075] (3) Cooling process: After pulverizing at room temperature, the temperature is then lowered to -18℃. This only reduces the storage temperature. However, since the cell wall has been unevenly damaged during the pulverization process, subsequent low-temperature storage cannot compensate for the oxidation loss and aroma volatilization that have already occurred.

[0076] (4) Quality of finished beer: The IBU value is only 22.5 (about 32-35 in Example 1, calculated based on the same α-acid equivalent feed). The aroma sensory score is 4.8 / 10, which shows that the aroma is weak and lacks typical hop characteristics. Some tasters reported that there is a slight oxidized taste.

[0077] Conclusion: Comparative Example 3 shows that the process sequence of room temperature grinding followed by cooling leads to cell sap leakage, α-acid oxidative degradation, and severe aroma volatilization, with a much lower retention rate of active ingredients than in Example 1. Room temperature grinding results in high hop moisture content and toughness, making uniform crushing impossible, and the mechanical heat and aerobic environment during the crushing process directly damage flavor quality. The pre-cooling (4°C) followed by low-temperature (-18°C) grinding sequence described in this invention is crucial for protecting hop quality.

[0078] Comparative Example 4 The process and conditions are the same as in Example 1, except that: In step (1) of the preparation of fresh hops, fresh Marco Polo hops grown in Xinjiang are harvested in mid-September. Within one hour of harvesting, they are transported to the processing workshop in the dark. After being removed by a magnetic separator, the hops are rapidly cooled from room temperature of 25°C (20–30°C) to -18°C using a low-temperature tunnel (1.05m × 16.0m) with an internal cold air temperature of -18°C. The hops are then crushed to a particle size of 0.2–0.5 cm.

[0079] Usage results: (1) Cooling effect: Hops were cooled directly from room temperature (25℃) to -18℃ by -18℃ cold air. The time required for the core temperature to drop to the target temperature was approximately 40-50 minutes (Example 1 involved two-stage cooling: 25℃→4℃ took approximately 10-15 minutes, and 4℃→-18℃ was completed instantly), resulting in a slow cooling rate. During the slow cooling process, large-sized ice crystals (>100 μm) formed inside and outside the hop cells, causing irreversible mechanical puncture damage to the cell walls. Microscopic observation showed that although the cell wall rupture rate reached 68.2%, the rupture morphology was mainly tearing and irregular breakage (Example 1 showed uniform brittle breakage with small and uniform pore size).

[0080] (2) Crushing effect: The hops were fully frozen and brittled under the crushing condition of -18℃. The proportion of particles with a particle size ≤0.5 cm was 89.5% by sieving, which is close to that of Example 1 (≥92%).

[0081] (3) State after thawing: After thawing, the hop powder in Comparative Example 4 showed obvious juice seepage and darkening of color (L The value was 5.2 lower than that in Example 1. This is because after the large ice crystals pierced the cell wall, the intracellular contents (including α-acids, polyphenols, and enzymes) leaked out during thawing. After they came into contact with each other, they underwent enzymatic oxidation, resulting in browning and loss of bitter substances.

[0082] (5) Finished beer quality: IBU value is 29.6 (approximately 32-35 in Example 1), aroma sensory score is 6.5 / 10, which shows that the aroma is acceptable but lacks fineness, and the beer has a slight astringency (due to polyphenol oxidation polymerization).

[0083] Conclusion: Comparative Example 4 shows that although pulverization after cooling to -18℃ achieves good physical pulverization, the rapid cooling process without pre-cooling at 4℃ results in relatively slow cooling rates (compared to cryogenics), leading to coarse ice crystals formed inside and outside the cells. This causes irreversible damage to the cell walls, resulting in the loss and oxidation of effective components after thawing. The pre-cooling to 4℃ followed by low-temperature pulverization in Example 1 avoids ice crystal damage and achieves low-temperature embrittlement pulverization, which is a key technological feature for protecting hop quality.

[0084] Comparative Example 5 The process and conditions are the same as in Example 1, except that: In step (2) the thawing process of fresh-locked hops, take the fresh-locked crushed hop block (5.0 kg, 40 cm × 40 cm × 5 cm) prepared in step (1), take it out along with the aluminum foil bag, and place it at room temperature of 20–25℃ in the dark for 3.5 hours to thaw until there are no visible ice crystals on the surface of the hops and a small amount of ice is still formed in the center. The temperature in the middle of the hop block is -8℃.

[0085] Usage results: (1) Thawing uniformity: After 3.5 hours of thawing, the thermocouple thermometer showed that the surface temperature of the flower block had reached 2℃, while the temperature in the middle was still -8℃, and the temperature difference between the surface and the center was as high as 10℃. The surface had completely thawed and heated up, while the center was still a frozen block, and the thawing was extremely uneven.

[0086] (2) Dispersion of feed: Because the center of the hops is still in a hard ice state, it cannot be dispersed quickly after being put into the boiling pot, and large ice-like hops sink directly to the bottom of the pot. Under local high temperature (100℃) heating, the ice crystals melt rapidly, causing local bursts, resulting in excessive cell wall breakage (breakage rate of more than 95%), releasing a large amount of grassy precursor substances (including hexanal, 2-hexenal and other C6 aldehydes).

[0087] (4) Quality of finished beer: The IBU value was 34.2 (similar to Example 1, as α-acid isomerization was not significantly affected). The aroma sensory score was 4.2 / 10, significantly lower than the 8.5 score of Example 1. The tasting notes showed that the grassy and raw green notes were prominent, covering the normal hop aroma, and the taste was rough and astringent, with an overall unbalanced flavor. The sensory evaluation score was 76.8, which only meets the first-class beer standard and does not meet the superior standard (≥90 points).

[0088] Conclusion: Comparative Example 5 shows that an excessively short thawing time (3.5 hours, core temperature -8°C) results in the center of the beer chunks remaining hard ice. After feeding, these large ice chunks directly contact the high-temperature wort, causing a rapid phase transition that leads to excessive cell breakage, releasing grassy flavor precursors and severely degrading the beer's flavor. This invention controls the thawing time to 4.5–5.5 hours and precisely achieves a core temperature of 4°C, ensuring uniform thawing and consistent flavor quality.

[0089] Comparative Example 6 The process and conditions are the same as in Example 1, except that: In step (2) the thawing process of fresh-locked hops, take the fresh-locked crushed hop block (5.0 kg, 40 cm × 40 cm × 5 cm) prepared in step (1), take it out along with the aluminum foil bag, and place it at room temperature of 20–25℃ in the dark for 9 hours to thaw until there are no visible ice crystals on the surface of the hops and a small amount of ice is still formed in the center. The temperature in the middle of the hop block is 15℃.

[0090] Usage results: (1) Thawing status: After 9 hours of thawing, the hops were completely thawed, with a core temperature of 15℃ (close to room temperature), and both the surface and core temperatures were 20–22℃, indicating complete softening. The color of the hop powder changed from bright green to dark yellowish-green (L). The value decreased by 8.3, indicating that significant oxidation had occurred.

[0091] (2) Enzymatic oxidation loss: Long-term room temperature storage (9 hours) allowed polyphenol oxidase (PPO) and lipoxygenase (LOX) in hops to fully recover their activity. The results showed that the total polyphenol content decreased by 32.6% compared with that before thawing, and the content of hexanal (an oxidative off-flavor marker) increased by 4.8 times.

[0092] (3) Microbial risk: The total bacterial count increased from <10 CFU / g before thawing to 2.6×10⁻⁶. 4 CFU / g poses a significant safety risk.

[0093] (4) Quality of finished beer: The aroma sensory score was 3.8 / 10, which indicates a weak aroma and a noticeable oxidized smell. Some tasters described it as having a "cardboard smell" and a "stale smell". The IBU value is 30.5 (similar to Example 1, with relatively little loss of bitter substances). The sensory evaluation score was 68.5, which is lower than the national standard for excellent and first grade, and therefore it was deemed unqualified.

[0094] Conclusion: Comparative Example 6 shows that excessively long thawing time (9 hours, core temperature 15℃) leads to a triple degradation of flavor due to enzymatic oxidation, aroma volatilization, and microbial proliferation, resulting in beer with severely degraded flavor that fails to meet commercial quality requirements. This invention precisely controls the thawing endpoint temperature to 4℃, ensuring complete thawing before feeding while minimizing quality loss.

[0095] Comparative Example 7 The process and conditions are the same as in Example 1, except that: In step (3), during the addition of fresh-locking hops, thawed hops are added 5 minutes into the initial boiling of the wort (the amount added is 0.10% of the wort volume, (w / v), equivalent to 100g / 100L wort, with a wort volume of approximately 50KL). After boiling for 60 minutes, the wort enters the whirlpool sedimentation stage, where thawed hops are added (the amount added is 0.02% of the wort volume, (w / v), equivalent to 20g / 100L wort, with a wort volume of approximately 50KL); after whirlpool sedimentation for 20 minutes, the wort is cooled to 9°C.

[0096] Usage results: (1) Bitterness value (IBU): Due to the excessively high proportion added at the beginning of boiling (0.08% in Example 1), the α-acids were fully isomerized during the 60-minute boiling process, and the IBU value of the finished beer reached 46.8, which is much higher than the approximately 32-35 in Example 1 and the style target value (19-24 BU). The beer has a significantly heavier bitterness and a strong astringent taste.

[0097] (2) Aroma characteristics: The proportion added during the swirling sedimentation stage was too low (0.02%, compared to 0.04% in Example 1), and the hop essential oil supplementation was insufficient. The aroma sensory score was 4.5 / 10, which showed that the bitterness masked the aroma, lacked fresh floral and fruity aromas, and the overall flavor was unbalanced in terms of bitterness and aroma.

[0098] (3) Sensory evaluation score: The overall score was 72.3 out of 100, barely meeting the standard of Grade 1 beer. The evaluation record showed that: "The bitterness was sharp and rough, the aroma was weak, the bitterness lingered in the mouth for a long time, and the aftertaste was unpleasant."

[0099] Conclusion: Comparative Example 7 shows that an excessively high proportion during the boiling stage results in excessive bitterness and astringency, while an excessively low proportion during the swirling sedimentation stage leads to insufficient aroma, resulting in a severe imbalance between bitterness and aroma. The addition ratio of 0.08% (boiling) / 0.04% (swirling) in this invention achieves the optimal balance between bitterness and aroma.

[0100] Comparative Example 8 The process and conditions are the same as in Example 1, except that: In step (3), during the addition of fresh-locking hops, thawed hops are added 5 minutes into the initial boiling of the wort (the amount added is 0.06% of the wort volume, (w / v), equivalent to 100g / 100L wort, with a wort volume of approximately 50KL). After boiling for 60 minutes, the wort enters the whirlpool sedimentation stage, where thawed hops are added again (the amount added is 0.06% of the wort volume, (w / v), equivalent to 20g / 100L wort, with a wort volume of approximately 50KL). After whirlpool sedimentation for 20 minutes, the wort is cooled to 9°C.

[0101] Usage results: (1) Bitterness value (IBU): Due to the low addition ratio in the early stage of boiling (0.06%, compared to 0.08% in Example 1), the total amount of α-acid isomerization was insufficient, and the IBU value was only 24.3, which was lower than that of Example 1 (approximately 32–35) and the style target value (19–24 BU, which is at the lower limit). The beer had a weak bitterness, a prominent sweetness of malt, and lacked the necessary bitterness support.

[0102] (2) Aroma characteristics: The proportion added during the whirl sedimentation stage is relatively high (0.06%, 0.04% in Example 1). This is because the wort temperature is still as high as 85–95°C during the whirl sedimentation stage. A large amount of hop oil is lost by volatilization with hot steam during the 20-minute whirl process. The marginal benefit decreases after the amount added exceeds a certain threshold.

[0103] (3) Aroma quality: The aroma sensory score is 5.2 / 10, which shows that the aroma intensity is moderate but lacks layering and freshness. Some terpenes exhibit herbal and spicy characteristics when added in higher amounts, rather than the ideal citrus / floral and fruity aroma.

[0104] (4) Overall flavor evaluation: The overall flavor is mildly bitter and mellow, with malt sweetness dominating. The hop characteristics are not prominent, and it lacks the three-dimensional layering of Example 1. The overall score is 78.6 out of 100, which is the lower limit of Grade 1 beer.

[0105] Conclusion: Comparative Example 8 shows that even though the total addition amount is the same as in Example 1 (0.12%), the improper distribution ratio between the two stages (0.06% / 0.06%) resulted in insufficient bitterness and wasted aroma, failing to achieve optimal flavor expression. The 0.08% (boiling) / 0.04% (whirling) ratio of this invention ensures sufficient bitter isomerization while avoiding aroma loss due to high addition amounts in the whirling stage, achieving optimal synergistic release of bitter substances and aroma components.

[0106] I. Basic conditions for evaluating the stability of microorganisms 1. Test specimen Example 1: Fresh-locking hops, added during boiling process Comparative Example 1: Conventional Particle Hops Comparative Example 2: Fresh Hops 2. Evaluation Environment and Judgment Criteria 1. Sensory evaluation Environment: Odorless, naturally lit tasting room, ambient temperature 20±2℃. Scoring Rules: 10-point scale; higher scores indicate better aroma performance. Evaluation dimensions: aroma intensity, natural freshness, and average scores from multiple tasters. 2. Turbidity detection Testing standard: EBC (turbidity unit); the lower the value, the clearer and more transparent the wine. 3. Microbiological stability (determined according to GB 4789.2 (Reference 3)) Storage conditions: Store at room temperature in a sealed container for 3 months. Testing indicator: Total bacterial count; the lower the value, the better the antibacterial and preservation effect. 4. Production adaptability Statistics on the natural time periods suitable for purchasing and feeding hops into production 5. Raw material cost accounting: Total cost of hops consumed per ton of finished beer, including seasonal premiums and storage and transportation losses. II. Complete Evaluation Process 1. The brewing process involves group feeding of raw materials, while the remaining saccharification, fermentation, and bottling process parameters are kept consistent. 2. After the finished wine has been allowed to stand and stabilize, three sensory evaluations are conducted simultaneously, and the scores are summarized and recorded. 3. The EBC turbidity values ​​of each group of wines were measured using instruments. 4. After sealing and storing at a constant temperature for 90 days, measure the total bacterial count according to GB 4789.2 (Reference 3). 5. Analyze the production time ranges for the three types of hops and calculate their economic costs. 6. Compare various indicators horizontally to comprehensively determine the advantages and disadvantages of hop application. III. Comprehensive Data Analysis 1. Aroma profile: Fresh hops offer the best freshness and intensity; hops with preserved freshness have a moderate aroma; hops with granular texture have a weaker aroma. 2. Appearance of the beer: The fresh hop group has the lowest turbidity and the beer is clear; the fresh hop group has higher turbidity. 3. Storage resistance and antibacterial properties: Fresh hops exhibit the best microbial stability, while fresh hops show significant bacterial contamination and a prominent short shelf life. 4. Practicality in production: Fresh hops and pellet hops can be produced year-round, while fresh hops are limited by the season and cannot be mass-produced year-round. 5. Cost-effectiveness: Pellets have the lowest cost, fresh hops have a high premium and therefore high cost, while hops with preserved freshness have a moderate cost. Appendix: Examples of Sensory Comparison Scoring Scheme

[0107] Complete sensory evaluation procedure (strictly following Chapter 6 of GB / T 4928-2026) (Reference 2) Step 1 Sample preparation: 1. Except for the hops, all processes, raw materials, boiling intensity, whirlpooling, fermentation, and filtration are standardized for both beers to eliminate variables; fresh hops and pellet hops are added in equal α-acid equivalent amounts. 2. The wine samples were kept at a constant temperature of 12-15℃ and randomly numbered A / B. The judges were unaware of the raw material type (blind tasting). 3. Standard tasting glasses are uniformly cleaned and free of residual odors; wine is poured at a uniform height and speed, with consistent markings on the liquid level. Step 2 Appearance Assessment: Under natural light, the clarity, suspended matter, and sediment were recorded by viewing from the side and from above, and the turbidity data were compared and scored; the difference in turbidity caused by fresh hop grass debris and fine particulate powder was distinguished.

[0108] Step 3 Foam Assessment: Observe the color, density, and clinging to the cup of foam; simultaneously record the foam holding time (national standard instrument method / manual timekeeping) and score according to the standard.

[0109] Step 4 Aroma Assessment: 1) Static smelling: Hold the cup with the rim below the nasal cavity and smell the basic aroma. 2) Dynamic Smelling: Gently shake the cup to release volatile essential oils and deeply smell; distinguish between fresh fruit aromas (fresh hops) and hay and resin aromas (granular), and record any off-odors such as raw green, oxidized, or earthy smells that will result in deductions. Step 5: Overall Taste Evaluation Take 10-15mL of the wine sample, spread it on the tongue, chew for 3 seconds and swallow; evaluate in three stages: aroma on the palate, smoothness of bitterness in the middle, and off-flavors / freshness in the finish, to assess the harmony of the wine.

[0110] Step 6: Data Statistics and Judgment 1. Collect all judges' scores, remove the highest and lowest scores, and calculate the average score.

[0111] 2. Determine product grade based on total score: ≥90 - Excellent; 80-89 - Lower limit of Excellent; 70-79 - Grade 1; <70 - Unqualified. (Reference 1) 3. Provide a sensory report, detailing the flavor differences between the two types of hops and the reasons for any deductions. Practical comparison results

[0112] Conclusions from production practice 1. Freshness-locking hops are significantly superior to pellet hops in terms of aroma freshness and flavor complexity, making it easier to meet national standards for quality. High-end sensory standards; 2. The advantages of pellet hops are easy control of clarity, stable storage, and simple feeding, but the upper limit of flavor is affected by drying. Due to processing limitations, the overall sensory score is consistently lower than that of frozen fresh hops; 3. Risks associated with freshness-locking hops: Overfeeding can result in raw, grassy hops and a large amount of plant debris, negatively impacting the appearance. The process requires matching and optimizing vortex sedimentation and filtration.

[0113] IV. Adaptation of References [Reference 1] Standardization Administration of China. GB / T 4927-2025 Quality Requirements for Beer [S]. Beijing: China Standards Press, 2025. [Reference 2] Standardization Administration of China. GB / T 4928-2026 Methods for beer analysis [S]. Beijing: China Standards Press, 2026. [Reference 3] National Health Commission of the People's Republic of China. GB 4789.2 National Food Safety Standard - Microbiological Examination of Food - Determination of Total Colony Count [S]. Beijing: China Standards Press. [Reference 4] Guan Dunyi. Beer Industry Handbook [M]. Beijing: China Light Industry Press. This invention discloses a brewing process using fresh-locked hops, belonging to the field of beer brewing technology. This invention uses commercially available fresh-locked hops as raw material, and through optimized thawing treatment and addition timing, utilizes the thawed fresh-locked hops for beer brewing. This invention directly uses commercially available fresh-locked hops, eliminating the need for in-house processing and simplifying operation. Through a systematic thawing and addition process, it maximizes the retention and release of α-acids, β-acids, and volatile components from fresh hops. Compared to pellet hop processes, this invention produces hops with a smaller feed amount (at the same moisture content), better foam retention, and typical "fresh hop" characteristics. Compared to fresh hop processes, this invention allows for year-round production with more stable quality. This invention provides an efficient and economical solution for the industrial production of hop-flavored beer.

[0114] This invention is the first to use commercially available fresh-locked hops (crushed at low temperature, vacuum-packed with nitrogen, and frozen at -18°C or below) as the direct brewing raw material. Through a system-optimized rapid thawing process (4–6 hours, surface softening, and trace amounts of ice crystals in the center) and the timing of staged addition (early boiling stage + swirling sedimentation stage), the α-acids, β-acids, and volatile terpenoid aroma components in fresh hops are preserved to the greatest extent and released in a synergistic manner.

[0115] Compared with existing technologies: Compared to traditional pellet hops: This invention completely eliminates the high-temperature and aerobic processes such as drying and pelleting, increases the α-acid retention rate by more than 20%, increases the volatile aroma retention rate by more than 50%, reduces the amount of feed by 15-25%, and the beer has a typical fresh hop aroma and pure bitterness, with better foam retention. Compared to direct hop planting with fresh hops, this invention overcomes the limitation of a harvest season of only 4–6 weeks, enabling balanced industrial production throughout the year. Furthermore, freezing and vacuum packaging significantly reduce the risk of microorganisms, resulting in more stable quality.

[0116] This invention directly uses commercially available frozen products, eliminating the need for breweries to process them themselves. It is simple to operate and cost-effective, providing an efficient and economical solution for the year-round large-scale production of fresh hop-flavored beer, and has significant industrial practical value.

Claims

1. A method for brewing beer using fresh-locking hops, characterized in that, Includes the following steps: (1) Preparation of fresh hops: Fresh hops are harvested, and after impurities are removed, pre-cooled and cooled, pulverized at low temperature, and vacuum-packed with nitrogen, they are frozen and stored at -18℃ to obtain fresh hops; (2) Thawing treatment of fresh hops: Thaw the fresh hops obtained in step (1) at room temperature in the dark until the temperature in the middle of the hop block is 2–5℃; (3) Preparation of wort: The malt is crushed and mixed with water, then saccharified and filtered to obtain wort, which is then boiled; (4) Addition of fresh-locking hops: Add the thawed fresh-locking hops from step (2) during the boiling and / or whirlpool sedimentation stages of the beer brewing process; (5) Fermentation, filtration and filling: yeast is inoculated for fermentation, and after fermentation, the mixture is filtered through diatomaceous earth and membrane, filled and pasteurized.

2. The method according to claim 1, characterized in that, In step (1), the fresh hops are transported to the processing workshop in the dark within 1 hour after harvesting. After being removed by a magnetic separator, they are first pre-cooled in a low-temperature tunnel to 2–5℃, and then transferred to a low-temperature pulverizing workshop below -18℃ to be pulverized to a particle size of 0.2–0.5 cm. Then, they are packed into light-proof aluminum foil bags at a rate of 3.0–10.0 kg per bag. After being vacuumed and nitrogen-filled twice, the bags are sealed to ensure that the residual oxygen volume concentration inside the bags is <0.5%. Finally, they are transferred to a cold storage at below -18℃ and laid flat for storage. The total time from harvesting to completion of frozen storage is controlled within 3 hours. The hop varieties used for freshness preservation are selected from one or more hop varieties produced in Xinjiang.

3. The method according to claim 1, characterized in that, In step (2), the fresh-locked hops are in block form, with a block size of 40 cm × 40 cm × (3–10 cm) and a weight of 3.0–10.0 kg per block. The thawing process is as follows: the fresh-locked hops are taken out together with the aluminum foil bag and placed at room temperature of 20–25°C in the dark for 4.5–5.5 hours until the temperature in the middle of the hop block is 2–5°C.

4. The method according to claim 1, characterized in that, The addition during the boiling stage mentioned in step (4) is as follows: when the wort has been boiling for 4-6 minutes in the initial stage of boiling, the amount added is 0.07%-0.09% (w / v) of the wort volume. The addition during the whirlpool sedimentation stage in step (4) is as follows: it is added at the beginning of whirlpool sedimentation, and the amount added is 0.03%–0.05% (w / v) of the wort volume.

5. The method according to claim 1 or 4, characterized in that, The freshness-locking hops mentioned in step (4) are added in two stages, one in the boiling stage and the other in the swirling sedimentation stage. The ratio of the amount added in the boiling stage to the amount added in the swirling sedimentation stage is (1.5-3):

1.

6. The method according to claim 1, characterized in that, The wort preparation described in step (3) includes: (a) Gelatinization: Take 3200–4000 kg of crushed rice, add 8.2–10.25 kL of water, adjust the temperature of the slurry to 60±1℃, raise the temperature to 70±1℃ at a rate of 0.5–1℃ per minute, keep it at this temperature for 8–12 minutes, then raise it to 93±2℃ and keep it at this temperature for 30–40 minutes to obtain the gelatinized product; (b) Saccharification: Take 5450–6800 kg of malt and saccharify it at a material-to-water ratio of 1:3–1:

4. Add the malt at 50±2℃ and decompose the protein for 45±5 minutes. Add the gelatinized product and mix with mash. Saccharify at 64±2℃ for 40±5 minutes. Raise the temperature to 72±1℃ and saccharify for 30±5 minutes. Then raise the temperature to 76–78℃ until there is no blue color reaction when tested with iodine. (c) Filtration and boiling: After saccharification, filter the wort, collect it and boil it for 60–70 minutes, with the boiling intensity controlled at 8–9%.

7. The method according to claim 1, characterized in that, The fermentation described in step (5) is as follows: inoculation with Lager yeast at a yeast inoculation rate of 1.2–2.5 × 10⁻⁶. 5 The wort volume was 10 mg / mL, the primary fermentation temperature was controlled at 10±0.2℃, and the saccharide content was reduced to 3.8–4.0°BX. The jars were then sealed, and the jar pressure was controlled at 0.08±0.01 MPa. After sealing, the temperature was raised to 12±0.2℃ for diacetyl reduction. When the diacetyl content dropped to below 0.06 mg / L, the temperature was lowered to -0.5±0.5℃ for storage.

8. The method according to claim 1, characterized in that, The two vacuuming and nitrogen filling processes mentioned in step (1) are as follows: the first vacuuming is carried out to a vacuum level below -0.06 MPa (gauge pressure), and nitrogen with a volume purity of ≥99.5% is filled to atmospheric pressure; the second vacuuming is carried out to a vacuum level below -0.08 MPa (gauge pressure), and nitrogen is filled to atmospheric pressure again before sealing. The freshness-locking hops can be stably stored for 24-36 months at temperatures below -18°C under vacuum packaging in aluminum foil bags.

9. Beer brewed according to any one of claims 1-8.

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