roasted coffee

Abstract

The present invention relates to a method for roasting coffee, and in particular to a method for roasting green coffee after extraction at high pressure followed by low pressure roasting. A further aspect of the invention is a roasted coffee and a container for use in a beverage preparation machine, the container containing roasted coffee.

Description

Detailed Description of the Invention

[0001] [Technical field] The present invention relates to a method for roasting coffee, in particular a method for high pressure roasting followed by low pressure roasting of extracted green coffee. A further aspect of the invention is a roasted coffee and a container for use in a beverage preparation machine, the container containing the roasted coffee.

[0002] [Background technology] The characteristic aroma and taste of coffee is developed during roasting of the coffee beans: lighter roasts are usually associated with a stronger perceived acidity and more fruity and wine-like aromatic notes, while darker roasts produce a fuller body and stronger roast notes.

[0003] Not all coffee drinkers share the same preferences when it comes to coffee aroma and taste, and in fact, many coffee drinkers enjoy the wide variety of sensory experiences that coffee can offer, with differences in bean type, origin, blend, and roasting method all playing a role.

[0004] When roasting coffee commercially, it is desirable to be able to control the taste and aroma of the coffee in order to create new sensory characteristics or to maintain consistency in the sensory characteristics of the coffee product over time and to compensate for changes in the seasonal availability of different coffee beans.

[0005] Therefore, there remains a need in the industry to find improved solutions for roasting coffee.

[0006] Any reference to a prior art document herein should not be construed as an admission that such prior art is well known or forms part of the common general understanding in the art. As used herein, the words "comprises," "comprising," and similar words should not be construed in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to."

[0007] [Summary of the Invention] The object of the present invention is to improve the state of the art. This object is achieved by the subject matter of the independent claims. The dependent claims further develop the inventive idea.

[0008] Thus, in a first aspect, the present invention provides a method for producing a composition comprising: a. roasting extracted green coffee at a pressure greater than 2 bar for 20 to 900 seconds, wherein the extracted green coffee contains sucrose in an amount less than 80% of the amount of sucrose in an unextracted sample of the same coffee before roasting; b. roasting the roasted and extracted coffee of step a at a coffee temperature of 180°C to 260°C for 20 to 1200 seconds at a pressure of 0.5 bar to 1.5 bar.

[0009] In a second aspect, the present invention provides roasted coffee having a weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine of greater than 4.

[0010] A third aspect of the present invention relates to a container for use in a beverage preparation machine, containing roasted coffee of the present invention.

[0011] Surprisingly, the inventors have discovered that roasting brewed coffee in two stages, i.e., a first roasting stage at high pressure and a second roasting stage at low pressure, e.g., atmospheric pressure, results in an enhanced ability to tailor the coffee to different taste regions, enhanced production of lightly toasted cereal notes, improved freshly roasted character, and reduced earthy, medicinal notes typically associated with Robusta coffee. In particular, the resulting roasted coffee possesses a combination of high levels of aroma compounds associated with desirable lightly roasted cereal notes, bready notes, e.g., dimethyl disulfide, and low levels of aroma compounds associated with earthy notes characteristic of darkly roasted Robusta coffee, e.g., pyrazines. This effect occurs with both Robusta and Arabica coffee beans.

[0012] [Mode for Carrying Out the Invention] The invention therefore relates, in part, to a method of roasting coffee, the method comprising: a) roasting extracted unroasted coffee (e.g., extracted green coffee beans) for 20 to 900 seconds at a pressure greater than 2 bar, wherein the extracted unroasted coffee contains sucrose in an amount less than 80% of the amount of sucrose in an unextracted sample of the same coffee before roasting; and b) roasting the roasted extracted coffee of step a for 20 to 1200 seconds at a pressure of 0.5 bar to 1.5 bar and a coffee temperature of 180°C to 260°C.

[0013] Surprisingly, the present inventors have found that roasting extracted green coffee by steps a) and b) results in a coffee with a pleasant sensory profile enhanced with lightly roasted cereal notes. For example, the resulting coffee may have a weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine greater than 4. Furthermore, the resulting coffee exhibits a reduction in earthy, medicinal notes, attributes typically unfavorably associated with Robusta coffee. The coffee also exhibits a strong reduction in associated guaiacol, for example, a weight ratio of guaiacol to dimethyl disulfide less than 30. Surprisingly, the method of the present invention is capable of producing a desirable flavor profile from extracted green coffee from which water-soluble coffee flavor precursor molecules, such as monosaccharides, disaccharides, amino acids, chlorogenic acid, and trigonelline, have been largely removed. Green coffee extract may provide valuable side-streams, for example, as a source of caffeine (a cognitive enhancer that improves wakefulness and attention), chlorogenic acid (an antioxidant), and trigonelline (a beneficial nutritional factor).

[0014] Roasting extracted green coffee at a pressure higher than 2 bar can be achieved, for example, by roasting extracted green coffee in gas pressurized to a pressure higher than 2 bar.

[0015] Green coffee is a term used for unroasted coffee. Extracted green coffee is unroasted coffee from which some of its components have been extracted, for example, by water extraction of green coffee beans. Sucrose is the most abundant sugar in unroasted coffee, at approximately 8% by weight in Arabica coffee beans and approximately 3-6% by weight in Robusta coffee beans. Extracted green coffee according to the present invention is extracted to contain less than 80% of the amount of sucrose in an unextracted sample of the same coffee. For example, Robusta coffee beans containing 6% by weight of sucrose in the unprocessed state contain less than 4.8% by weight of sucrose in the extracted green coffee beans. In some embodiments, extracted green coffee contains less than 60%, 40%, 30%, 20%, or 15% of the amount of sucrose in an unextracted sample of the same coffee before roasting. In one embodiment, the extracted green coffee contains less than 3% by weight of sucrose, these weight percentages of sucrose being expressed as a percentage of the dry weight of the coffee.

[0016] In one embodiment, roasting of the extracted green coffee according to step a is carried out in a rotatable perforated drum in a pressurizable chamber.

[0017] In step b, the roasted extracted coffee is roasted at a pressure around atmospheric pressure. For example, the extracted coffee can be roasted at a pressure of 0.8 to 1.2 bar, for example 0.9 to 1.1 bar.

[0018] The roasting of the extracted coffee roasted in step a in step b can be carried out in a suitable roasting apparatus, such as a drum roaster, a fluidized bed roaster, or a paddle roaster. The roasting in step b can also be carried out in an apparatus separate from the apparatus used to roast the extracted unroasted coffee in step a. In one embodiment, the roasting in step b is carried out in a fluidized bed roaster or a paddle roaster. The roasting in step b can be carried out under an inert atmosphere, for example, under nitrogen.

[0019] Many consumers expect the coffee they drink to be free of ingredients other than coffee beans. In one embodiment, the extracted unroasted coffee is roasted in the absence of any non-coffee ingredients, such as added sugar. In one embodiment, step b is performed in the absence of any non-coffee ingredients, such as added sugar. In a further embodiment, all roasting steps in the method for roasting coffee are performed in the absence of non-coffee ingredients, such as added sugar.

[0020] In some embodiments, the extracted unroasted coffee is roasted in the absence of any non-coffee bean raw materials, e.g., components other than coffee cherries. In some embodiments, the roasting in step b is carried out in the absence of any non-coffee bean raw materials, e.g., components other than coffee cherries. In further embodiments, all roasting steps in the method for roasting coffee are carried out in the absence of any non-coffee bean raw materials, e.g., components other than coffee cherries.

[0021] In one embodiment, the extracted unroasted coffee is obtained by extracting unroasted coffee (e.g., green coffee beans) with an aqueous liquid and then separating the extracted unroasted coffee from the extract. The unroasted coffee may be extracted for 10 minutes to 6 hours, for example, 30 minutes to 3 hours, further for example, 50 minutes to 90 minutes. The extraction may be countercurrent extraction. The aqueous fluid may be water. The aqueous liquid may be at a temperature of 20 to 100°C, for example, 75 to 95°C, for example, 60 to 90°C during extraction. The water:coffee weight ratio may be 2:1 to 5:1, for example, 2.5:1 to 4.5:1. At least 20% by weight, for example, at least 30%, 40%, 50%, or 60% by weight, of the soluble carbohydrates present in the unextracted unroasted coffee may be extracted into the aqueous liquid. The soluble carbohydrates remaining in the green coffee after extraction may be less than 5% by weight on a dry basis, for example, less than 4%, 3%, or 2% by weight on a dry basis. The extracted green coffee may be separated from the liquid by any suitable means, for example, filtration, centrifugation, and / or decantation. The extracted green coffee may be dried to a moisture content of, for example, 8 to 15% by weight, such as 8 to 13% by weight, further such as 9 to 12% by weight, before further roasting.

[0022] In the context of the present invention, unroasted coffee is coffee (e.g., coffee beans) that has not been exposed to a temperature high enough to initiate roasting. In one embodiment, the unroasted coffee has not been heated to a temperature higher than 110°C before extraction, for example, the unroasted coffee has not been heated to a temperature higher than 100°C, 90°C, or 80°C before extraction. In a further embodiment, the unroasted coffee has not been heated to a temperature higher than 110°C during extraction, for example, the unroasted coffee has not been heated to a temperature higher than 100°C or 90°C during extraction.

[0023] In one embodiment, the roasted extracted coffee in step a is combined with an aqueous unroasted coffee extract before being roasted in step b. Unroasted coffee extract is rich in water-soluble compounds, such as monosaccharides, disaccharides, amino acids, chlorogenic acid, and trigonelline. All of these are important precursors for flavor production, with monosaccharides, disaccharides, and amino acids being particularly important precursors. Without being bound by theory, the inventors believe that roasting the extracted unroasted coffee at high pressure reduces the levels of pyrazines (earthy notes) and guaiacols (phenolic, medicinal, smoky, and ashy notes) and reduces undesirable robusta characteristics. However, if the unroasted coffee extract is protected from these relatively harsh conditions and then reintroduced into a second roasting step at near ambient pressure, the flavor precursors in the unroasted coffee extract will react to form desirable flavors. For example, coffee may have a weight ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine greater than 0.6.

[0024] In one embodiment, the aqueous green coffee extract is concentrated, for example to 20-35% total solids, before being combined with the roasted extracted coffee of step a and roasted according to step b.

[0025] The aqueous green coffee extract may have most or all of the caffeine removed, for example so that when the roasted extracted coffee of step a is combined with the aqueous green coffee extract and roasted in step b, decaffeinated coffee is obtained. Caffeine can be removed by methods known in the art, for example, by contacting the coffee extract substances with activated carbon pre-impregnated to selectively remove the caffeine. The aqueous green coffee extract may contain less than 0.1% by weight of caffeine, for example less than 0.05% by weight of caffeine.

[0026] The roasted extracted coffee may be combined with the aqueous unroasted coffee extract in a mixer, for example, a stirred jacketed mixer. The roasted extracted coffee may be held at a slight vacuum, for example, 0.65 to 0.95 bar, immediately before and / or during combination with the aqueous unroasted coffee extract. Such holding helps maximize the incorporation of the aqueous unroasted coffee extract into the roasted extracted coffee. Any aqueous unroasted coffee extract not incorporated by the beans is removed, for example, by sieving. In one embodiment, the roasted extracted coffee may be combined with the aqueous unroasted coffee extract in a coffee-to-extract ratio of 2:1 to 10:1 on a solids basis. This ratio is the ratio of the aqueous unroasted coffee extract to the amount of the aqueous unroasted coffee extract incorporated by the roasted extracted coffee. Preferably, the amount of aqueous unroasted coffee extract is selected so that it is completely absorbed by the roasted extracted coffee, but any excess aqueous unroasted coffee extract present is removed, for example, by sieving. For the purposes of calculating the ratio of roasted extracted coffee to unroasted coffee aqueous extract, any excess unroasted coffee aqueous extract is not included. After combining the roasted extracted coffee with the unroasted coffee aqueous extract, it may be rinsed with fresh water. After combining with the unroasted coffee aqueous extract and before roasting in step b, the roasted extracted coffee may be dried, for example to a moisture content of 8 to 15% by weight, such as 8 to 13% by weight, further such as 9 to 12% by weight.

[0027] In one embodiment, the aqueous green coffee extract is obtained by extracting green coffee (e.g., green coffee beans) with an aqueous liquid and then separating the extracted green coffee from the extract. The green coffee may be extracted for 10 minutes to 6 hours, for example, 30 minutes to 3 hours, and further for example, 50 minutes to 90 minutes. The extraction may be countercurrent extraction. The aqueous fluid may be water. The aqueous liquid may be at a temperature of 20 to 100°C, for example, 75 to 95°C, for example, 60 to 90°C during extraction. The water:coffee weight ratio may be 2:1 to 5:1, for example, 2.5:1 to 4.5:1. The aqueous green coffee extract may contain sucrose at a level of, for example, 15 to 45% by weight on a dry weight basis, further for example, 20 to 40% by weight on a dry weight basis. The aqueous extract of green coffee may contain amino acids at a level of, for example, 0.8 to 4.0% by weight on a dry basis, and further for example, 1.0 to 3.8% by weight on a dry basis. The aqueous extract of green coffee may contain free phenols at a level of, for example, 15 to 40% by weight on a dry basis, and further for example, 20 to 35% by weight on a dry basis. Examples of free phenols include caffeoylquinic acid, dicaffeoylquinic acid, and feruloylquinic acid. The aqueous extract of green coffee may contain trigonelline at a level of, for example, 1.5 to 4.0% by weight on a dry basis, and further for example, 2.0 to 3.5% by weight on a dry basis. The aqueous extract of green coffee may contain caffeine at a level of, for example, 3 to 15% by weight on a dry basis, and further for example, 4.5 to 10% by weight on a dry basis. The aqueous green coffee extract may be decaffeinated and may contain less than 0.5% by weight on a dry basis, for example less than 0.25% by weight on a dry basis, hi one embodiment, the aqueous green coffee extract contains sucrose at a level of 15-45% by weight on a dry basis, amino acids at a level of 0.8-4.0% by weight, and trigonelline at a level of 1.5-4.0% by weight.

[0028] The aqueous unroasted coffee extract may have a total solids content of 10 to 50%, for example 20 to 30%. The aqueous unroasted coffee extract may be separated from the extracted unroasted coffee by any suitable means, for example, filtration, centrifugation, and / or decantation.

[0029] In one embodiment, the extracted green coffee is roasted in step a) in the presence of superheated steam at a pressure higher than 9.5 bar.

[0030] In an embodiment, the superheated steam has a pressure greater than 10 bar, such as greater than 11 bar, further such as greater than 12 bar. The superheated steam may have a pressure between 9.5 bar and 20 bar, such as between 10 bar and 19 bar, further such as between 12 bar and 18 bar.

[0031] Pressures given in this specification in the unit "bar" refer to absolute pressure, which may also be written as bara or bar(a). 1 bar is equal to 100 kPa.

[0032] The temperature of the steam should be such that the steam is superheated under the pressure of the steam, and the steam supply is sufficient to maintain a superheated steam atmosphere. Pressure-enthalpy phase diagrams for steam are widely available. Provided that the steam is superheated, the temperature of the steam may be between 180°C and 330°C, such as between 220°C and 320°C, or further such as between 250°C and 310°C. For example, the superheated steam may be at a pressure of 13 bar and a temperature of 300°C.

[0033] Roasting coffee in steam is generally not practiced because the resulting coffee tends to be sour. However, the roasting conditions used in the method of the present invention surprisingly avoid this sourness, leaving a desirable clean sourness, but without an unpleasant sourness.

[0034] In one embodiment, in step a), the extracted green coffee may be roasted in the presence of superheated steam to a final temperature (e.g., final bean temperature) of 180°C to 320°C, such as 190°C to 300°C, or further such as 200°C to 280°C.

[0035] In one embodiment, the moisture content of coffee (e.g., coffee beans) after roasting in the presence of superheated steam is less than the moisture content of unroasted beans. The superheated steam is "dry" in the sense that it does not contain water in the liquid phase. Simply steaming coffee with, for example, saturated steam before roasting cannot provide the desired taste adjustment; in fact, high levels of coffee moisture (e.g., 20% or more by weight of the beans), such as can be produced by steaming with wet steam, can result in undesirable sensory characteristics, such as undesirable sourness, and the development of undesirable sensory compounds when the beans are exposed to roasting temperatures.

[0036] In some embodiments, the roasted coffee has a titratable acidity of less than 20 mmol sodium hydroxide equivalent per 100 g of roasted coffee, such as less than 15 mmol sodium hydroxide equivalent per 100 g of roasted coffee, and further such as less than 5 mmol sodium hydroxide equivalent per 100 g of roasted coffee. Titratable acidity can be measured, for example, by suspending 10 g of roast and ground coffee in 200 mL of water and boiling. After boiling for 5 minutes with stirring and cooling, water is added to compensate for evaporation losses. The suspension is filtered, and 50 mL of the filtrate is titrated to pH 6.60 with 0.1 M aqueous sodium hydroxide.

[0037] Surprisingly, coffee obtained by roasting extracted coffee in step a) in the presence of superheated steam at a pressure higher than 9.5 bar and then combining it with an aqueous extract of unroasted coffee before roasting in step b) exhibits an improved sensory profile of "coffeeness". Thus, for example, coffee may have a weight ratio of dimethyl disulfide to methanethiol greater than 1.5.

[0038] In one embodiment, in step b, the roasted, extracted coffee is roasted without water vapor. By "roasted without water vapor" is meant that no water vapor is introduced into the coffee during roasting, although some water vapor may originally be generated from moisture in or on the coffee when it is heated.

[0039] In one embodiment, a method of roasting coffee comprises roasting extracted unroasted coffee in the presence of superheated steam at a pressure greater than 12 bar for 80-150 seconds, wherein the extracted unroasted coffee contains sucrose in an amount less than 80% of the amount of sucrose in an unextracted sample of the same coffee before roasting, followed by roasting without steam at a pressure of 0.8-1.2 bar and a coffee temperature of 180°C-220°C for 200-220 seconds.

[0040] Advantageously, the method of the present invention can produce from Robusta coffee the type of taste and aroma typically associated with light-roasted Arabica coffee. However, the coffee according to the present invention may be Arabica coffee (Coffea arabica), Robusta coffee (Coffea canephora), or a combination thereof. The coffee may essentially be coffee beans (seeds of the coffee plant) in the form of whole beans, split beans, ground beans, or a combination thereof.

[0041] In one embodiment, the extracted green coffee is roasted in the presence of an inert gas in step a). The pressure during roasting can be achieved by introducing an inert gas into the roaster under pressure. At least 98% of the gas atmosphere in which the beans are roasted may be an inert gas, for example, the partial pressure of the inert gas may be 98% of the total pressure. The inert gas may be nitrogen.

[0042] In some embodiments, the roasted coffee may be ground, for example, the coffee may be ground after step b.

[0043] Beverage preparation devices (e.g., beverage preparation machines) containing extractable portioned ingredients provide a convenient method of preparing beverages. Such portioned ingredients are generally packaged in containers configured, for example, as pods, pads, sachets, pouches, or capsules. In some embodiments, roasted coffee (e.g., roast and ground coffee beans) is filled into the container, which, when inserted into the beverage preparation device, prepares a beverage. The container may, for example, be a beverage capsule, among other configurations.

[0044] To best optimize the sensory characteristics of the coffee, the roast applied to a certain percentage of the beans in the final blend may be different from the roast applied to other beans in the blend. For example, in a blend of beans from different origins and / or different varieties, the coffee beans of different origins / varieties may be roasted separately under conditions that optimize the final flavor and aroma. In one embodiment, the beans after roasting in step b) are blended with further coffee beans roasted under different conditions.

[0045] In one embodiment, a method of roasting coffee beans includes roasting a first type of extracted unroasted coffee in the presence of superheated steam at a pressure greater than 9.5 bar for 20 to 900 seconds, wherein the extracted unroasted coffee contains sucrose in an amount less than 80% of the amount of sucrose in an unextracted sample of the same coffee before roasting; roasting the coffee roasted in the presence of superheated steam in a further roasting step without steam at a coffee temperature of 180°C to 260°C and a pressure of 0.8 to 1.2 bar for 20 to 1200 seconds; separately roasting a second type of unroasted coffee; and blending the first and second types of roasted coffee.

[0046] In some embodiments, the first type of extracted unroasted coffee is from a different origin and / or a different coffee species than the second type of unroasted coffee. The first type of extracted unroasted coffee may be of a lower quality grade than the second type of coffee beans. The first type of extracted unroasted coffee may be, for example, dry-processed Robusta or dry-processed Brazilian Arabica beans. The second type of unroasted coffee may be from a different origin and / or a different coffee species than the first type of coffee beans, and may be high-quality beans with an inherent fruity / floral aroma and good acidity. "Different origin" means that the beans are grown in a different geographic region or country. Examples of origins include Colombia, Kenya, Costa Rica, Nicaragua, and Brazil. The second type of unroasted coffee may be selected from the group consisting of Colombian Arabica, Kenyan Arabica, Central American Arabica (e.g., Costa Rican or Nicaraguan), high quality Brazilian Arabica, top quality Robusta, and combinations thereof.

[0047] The two roasting stages of the method of the present invention do not need to be performed in the same physical location. Roasters capable of roasting at high pressure or in the presence of superheated steam are generally more expensive than conventional roasters. It may be economically viable to establish a central facility where extracted coffee is roasted at high pressure (optionally in the presence of superheated steam), and then transport this pressure-roasted, exhausted coffee to a series of other locations, for example, locations close to the point of sale, for roasting in step b. When the roasted extracted coffee is combined with an unroasted aqueous coffee extract, this combination can also be performed in a central facility. The roasting in step b may be performed, for example, at home or in a retail store, broadening the coffee range through the attractive aromas that can be introduced. The beans are typically packaged in containers for transport. In one embodiment, the roasted extracted coffee of step a is packaged in containers and transported to at least one other location before being roasted in step b.

[0048] One aspect of the present invention provides a method of roasting coffee, comprising roasting extracted unroasted coffee at a pressure greater than 2 bar for 20 to 900 seconds, wherein the extracted unroasted coffee contains sucrose in an amount less than 80% of the amount of sucrose in an unextracted sample of the same coffee before roasting, followed by filling into a container. For example, the extracted unroasted coffee may be roasted to a color having a CTN greater than 100 and then filled into a container.

[0049] A further aspect of the invention is the use of roasted extracted green coffee for subsequent roasting at home or in a retail store, wherein the roasted extracted coffee has been subjected to roasting at a pressure higher than 2 bar for a period of 20 to 900 seconds, and wherein the extracted green coffee comprises sucrose in an amount less than 80% of the amount of sucrose in an unextracted sample of the same coffee before roasting.

[0050] The inventors have surprisingly found that roasted coffee according to the invention has improved sensory attributes, confirmed by an aroma chemistry that is atypical of beans roasted solely by conventional heat roasting: the balance of aroma compounds associated with lightly roasted cereal notes, e.g., dimethyl disulfide, to aroma compounds associated with earthy notes characteristic of dark roasted Robusta coffee, e.g., alkylpyrazines, is much higher in the roasted coffee.

[0051] One aspect of the present invention provides roasted coffee having a weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine greater than 4, for example, greater than 4.5, 5, 6, 7, 8, 9, 10, or 15. In one embodiment, the roasted coffee of the present invention has a weight ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine of 4.5 to 40. 2,3-diethyl-5-methylpyrazine is an aroma molecule that provides earthy notes.

[0052] Roasted coffee is a material obtained by roasting coffee beans, and may be, for example, roasted coffee beans or roast and ground coffee beans.

[0053] The weight of aroma compounds in roasted coffee, used to calculate the weight ratio, can be quantified using isotope-labeled standards in conjunction with solid-phase microextraction and gas chromatography-mass spectrometry after suspending the roast and ground coffee in water. This isotope dilution analysis (also called stable isotope dilution analysis) is a technique for volatile analysis that provides highly accurate measurements of the compound content in roasted coffee. By adding the labeled standards at the earliest possible stage of sample preparation, for example, directly into the roast and ground coffee suspension, all physicochemical phenomena that occur between the addition of the standards and the instrumental acquisition are fully compensated for.

[0054] For example, quantification can be performed by placing 5 g of roast and ground coffee in a screw-cap flask, suspending it in 100 mL of boiling water, capping it, stirring for 10 minutes, then cooling it on ice, adding a defined amount of labeled isotope of the analyte to the resulting slurry, then transferring an aliquot of the sample to a silanized glass vial, sealing it, and equilibrating it at room temperature for 60 minutes, after which the aroma compounds are extracted from the headspace by solid-phase microextraction at 40°C for 10 minutes and quantified by gas chromatography-mass spectrometry.

[0055] In one embodiment, the roasted coffee of the present invention has a weight ratio of guaiacol to dimethyl disulfide of less than 30, such as less than 20, less than 15, less than 12, less than 11, less than 10, or less than 9. In one embodiment, the roasted coffee of the present invention has a weight ratio of guaiacol to dimethyl disulfide of from 2 to 20, such as from 2.5 to 10, or further such as from 3 to 9. Guaiacol is an aroma molecule associated with phenolic, medicinal, and smoky notes. These notes are commonly associated with the characteristics of Robusta coffee and are generally considered undesirable.

[0056] In some embodiments, the roasted coffee of the present invention has a weight ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine of greater than 0.6, such as greater than 0.65, greater than 0.7, or greater than 0.75. In some embodiments, the roasted coffee of the present invention has a weight ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine of 0.6 to 5, such as 0.7 to 4, or further such as 0.75 to 3. An increase in the ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine is associated with a decrease in earthy note.

[0057] In one embodiment, the roasted coffee of the present invention has a weight ratio of dimethyl disulfide to methanethiol greater than 1.5, e.g., greater than 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 3.0, 3.5, 4.0, or 4.5. The roasted coffee of the present invention may have a weight ratio of dimethyl disulfide to methanethiol between 1.5 and 15.0, e.g., between 2.0 and 6.0, and further e.g., between 2.5 and 5.0. A higher dimethyl disulfide to methanethiol ratio is associated with increased "coffee-ness" from an organoleptic perspective. The method of the present invention is particularly effective for improving "coffee-ness" when the extracted unroasted coffee is roasted in the presence of superheated steam at a pressure greater than 9.5°C in step a and then combined with an aqueous unroasted coffee extract before roasting in step b. It is particularly surprising and advantageous that the method of the present invention can improve the "coffee-ness" of Robusta coffee. The roasted coffee of the present invention may be Robusta coffee, and the weight ratio of dimethyl disulfide to methanethiol may be greater than 1.5, for example, greater than 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 3.0, 3.5, 4.0, or 4.5. The roasted coffee of the present invention may be Robusta coffee, and the weight ratio of dimethyl disulfide to methanethiol may be 1.5 to 15.0, for example, 2.0 to 6.0, or further for example, 2.5 to 5.0.

[0058] In some embodiments, the roasted coffee of the present invention has a furfural to guaiacol weight ratio of greater than 3, e.g., greater than 4, 5, 6, or 7. In some embodiments, the roasted coffee of the present invention has a furfural to guaiacol weight ratio of 3 to 20. In some embodiments, the roasted coffee of the present invention is Robusta coffee and has a furfural to guaiacol weight ratio of greater than 3, e.g., greater than 4 or 5. In some embodiments, the roasted coffee of the present invention has a furfural to guaiacol weight ratio of 3 to 10. An increase in furfural is associated with an increase in bready, lightly roasted, and sweet notes. A decrease in guaiacol is associated with a decrease in phenolic, medicinal, and smoky notes. These notes are commonly associated with Robusta coffee characteristics and are generally considered undesirable.

[0059] In some embodiments, the roasted coffee of the present invention has a weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine greater than 4, and a weight ratio of guaiacol to dimethyl disulfide less than 30. In some embodiments, the roasted coffee of the present invention has a weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine greater than 4, and a weight ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine greater than 0.6. In some embodiments, the roasted coffee of the present invention has a weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine greater than 4, a weight ratio of guaiacol to dimethyl disulfide less than 30, and a weight ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine greater than 0.6. In some embodiments, the roasted coffee of the present invention has a weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine greater than 4, a weight ratio of guaiacol to dimethyl disulfide less than 30, a weight ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine greater than 0.6, and a weight ratio of dimethyl disulfide to methanethiol greater than 1.5.

[0060] Roasted bean color can be expressed in CTN units. CTN roast color ranges from 0 to 200 and is determined by measuring the intensity of infrared (IR) light (904 nm) backscattered by a sample when measured with a spectrophotometer such as the Neuhaus Neotec ColorTest II®. The spectrophotometer illuminates the surface of a ground sample with monochromatic IR light at a wavelength of 904 nm from a semiconductor light source. The amount of light reflected by the sample is measured by a pre-calibrated photodetector. A series of measurements is averaged and displayed by an electronic circuit. Coffee bean color varies depending on its roast level. For example, green coffee beans typically have a CTN greater than 200, extremely lightly roasted coffee beans typically have a CTN of around 150, lightly roasted coffee beans typically have a CTN of around 100, and medium-dark coffee beans typically have a CTN of around 70. Very dark roasted coffee beans typically have a CTN of around 45. The methods of the present invention enable the preparation of coffee with attractive aromas typically associated with light roasts, e.g., lightly roasted Arabica. Surprisingly, these aromas are maintained at relatively high roast levels. In one embodiment, the roast color of the roasted coffee is between 30 and 100 CTN, e.g., between 40 and 90 CTN.

[0061] In some embodiments, the roasted coffee is contained in a container that, when inserted into the beverage preparation device, prepares a beverage. The container may be, for example, a beverage capsule, among other configurations.

[0062] In some embodiments, the roasted coffee is roasted (e.g., partially roasted) coffee that has been packaged for further roasting. The packaged roasted coffee may be packed into bulk containers, for example, for inter-factory transport. The packaged roasted coffee may be packed into semi-bulk packs for further roasting at home or in retail outlets, for example, cafes.

[0063] An embodiment of the invention is roasted coffee packaged for further roasting, wherein the weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine is greater than 4 and the weight ratio of guaiacol to dimethyl disulfide is less than 30, for example less than 20, 15, 12, 11, 10 or 9.

[0064] In one embodiment, the roasted coffee (eg, partially roasted coffee) packaged for further roasting has a roast color of 75 to 160 CTN, for example, 100 to 150 CTN.

[0065] One aspect of the present invention is a container for use in a beverage preparation machine, the container containing roasted coffee of the present invention.

[0066] Those skilled in the art will understand that all features of the invention disclosed herein may be freely combined. In particular, features described for the method of the invention may be combined with the product of the invention, and vice versa. Furthermore, features described for different embodiments of the invention may be combined. Where known equivalents exist for particular features, such equivalents are incorporated as if specifically referred to herein.

[0067] Further advantages and features of the present invention are apparent from the non-limiting examples.

[0068] [Example] Example 1: Extraction of green coffee Green coffee beans were pre-moistened to a moisture content of 50-60% and then extracted for 60 minutes with water at 80-90°C in a water to bean weight ratio of 3.5:1 to yield extracted coffee beans and green coffee extract. The extracted coffee beans were dried to a moisture content of 12% by weight. The extracted coffee beans had a sucrose content of approximately 10% of the sucrose level in the beans before extraction. The aqueous green coffee extract from each coffee variety was concentrated to 25% total solids by evaporation.

[0069] Example 2: Two-step roasting, steam pressurization, no extract added Roasting under pressure with steam: 500 g of extracted coffee was weighed and manually fed into a rotatable perforated drum in a pressurizable chamber. The pressurizable chamber was isolated from the environment by a ball valve. The drum was rotated to start the coffee moving. Superheated steam at 13 bar and 300°C was metered into the pressurizable chamber. The pressure was selected to obtain a medium to dark roast color after both roasting steps without burning the beans. After 300 seconds, the flow of steam into the pressurizable chamber was stopped and the pressure was quickly reduced to atmospheric pressure. The direction of the rotating drum was reversed, allowing the coffee to be metered into the outlet of the pressurizable chamber. The processed coffee was then collected through a valve assembly at the bottom of the pressurizable chamber.

[0070] Roasting at atmospheric pressure without steam: 350 g of coffee roasted with steam as described above was placed in a perforated drawer that could be exposed to a stream of hot air at the desired temperature. The temperature of the coffee beans was measured by a temperature probe. After 300 seconds at 210°C, the roasted coffee was transferred to a cooling chamber and exposed to a stream of ambient temperature, stopping the roasting process. Samples were then removed from the cooling chamber. Arabica samples are referred to as SA, and Robusta samples as SB.

[0071] Example 3: Two-step roasting, steam pressurization, and extract addition Roasting under pressure with steam: 500 g of coffee beans were weighed after extraction and manually fed into a rotatable perforated drum in a pressurizable chamber. The pressurizable chamber was isolated from the environment by a ball valve. The drum was rotated to start the coffee moving. Superheated steam at 13 bar and 300°C was metered into the pressurizable chamber. The pressure was selected to obtain a medium to dark roast color after both roasting steps without burning the beans. After 300 seconds, the flow of steam into the pressurizable chamber was stopped and the pressure was quickly reduced to atmospheric pressure. The direction of the rotating drum was reversed, allowing the coffee to be metered into the outlet of the pressurizable chamber. The processed coffee was then collected through a valve assembly at the bottom of the pressurizable chamber.

[0072] Incorporation of extract into roasted, extracted beans: 2.85 kg of extracted beans roasted under steam pressure as described above were combined with 2.2 kg of coffee extract from Example 1 (the Arabica extract was combined with roasted, extracted Arabica beans, and the Robusta extract was combined with roasted, extracted Robusta beans). The extract had a total solids content of 25%. The beans and extract were gently mixed in a double-jacketed Stephan mixer with a rotating arm at 50°C for 24 hours. The beans absorbed all of the extract. After mixing, the beans were rinsed with fresh water and dried to a moisture content of 12%.

[0073] Roasting at atmospheric pressure without steam: 350 grams of roasted, extracted beans (as described above) incorporating the extract were placed in a perforated drawer that could be exposed to a stream of hot air at the desired temperature. The temperature of the coffee beans was measured by a temperature probe. After 300 seconds at 210°C, the roasted coffee was transferred to a cooling chamber and exposed to a stream of ambient temperature, stopping the roasting process. Samples were then removed from the cooling chamber. The Arabica sample is referred to as SEA, and the Robusta sample is referred to as SEB.

[0074] Example 4: Two-step roasting, nitrogen pressurization, and extract addition Roasting under pressure with nitrogen: 500 g of coffee beans were weighed after extraction and manually fed into a rotatable perforated drum in a pressurizable chamber. The pressurizable chamber was isolated from the environment by a ball valve. The drum was rotated to start the coffee moving. Superheated steam at 18 bar and 300°C was metered into the pressurizable chamber. The pressure was selected to obtain a medium to dark roast color after both roasting steps without burning the beans. After 300 seconds, the flow of nitrogen into the pressurizable chamber was stopped and the pressure was quickly reduced to atmospheric pressure. The direction of the rotating drum was reversed, allowing the coffee to be metered into the outlet of the pressurizable chamber. The processed coffee was then collected through a valve assembly at the bottom of the pressurizable chamber.

[0075] Incorporation of extract into roasted extracted beans: 2.85 kg of extracted beans roasted under nitrogen pressure as described above were combined with 2.2 kg of coffee extract from Example 1 (Arabica extract was combined with roasted extracted Arabica beans, and Robusta extract was combined with roasted extracted Robusta beans). The extract had a total solids content of 25%. The beans and extract were gently mixed in a double-jacketed Stephan mixer with rotating arms at 50°C for 24 hours. The beans absorbed all of the extract. After mixing, the beans were rinsed with fresh water and dried to a moisture content of 12%.

[0076] Roasting at atmospheric pressure: 350 grams of roasted, extracted beans (as described above) were placed in a perforated drawer that could be exposed to a stream of hot air at the desired temperature. The temperature of the coffee beans was measured by a temperature probe. After 300 seconds at 210°C, the roasted coffee was transferred to a cooling chamber and exposed to a stream of ambient temperature, stopping the roasting process. Samples were then removed from the cooling chamber. Arabica samples are referred to as NEA, and Robusta samples are referred to as NEB.

[0077] Example 5: Comparative Example Roasting under pressure with steam: 500 g of raw coffee beans were weighed and manually fed into a rotatable perforated drum in a pressurizable chamber. The pressurizable chamber was isolated from the environment by a ball valve. The drum was rotated to start the coffee moving. Superheated steam at 16 bar and 300°C was metered into the pressurizable chamber. The pressure was selected to obtain a medium to dark roast color after both roasting steps without burning the beans. After 300 seconds, the flow of steam into the pressurizable chamber was stopped and the pressure was quickly reduced to atmospheric pressure. The direction of the rotating drum was reversed, allowing the coffee to be metered into the outlet of the pressurizable chamber. The processed coffee was then collected through a valve assembly at the bottom of the pressurizable chamber.

[0078] 350 g of coffee roasted with steam as described above was placed in a perforated drawer that could be exposed to a stream of hot air at the desired temperature. The temperature of the coffee beans was measured by a temperature probe. After 300 seconds at 210°C, the roasted coffee was transferred to a cooling chamber and exposed to a stream of ambient temperature to stop the roasting process. Samples were then collected from the cooling chamber. The resulting coffees are referred to as SRefA (Arabica) and SRefB (Robusta).

[0079] Roasting under pressure with steam: 500 g of unextracted coffee beans were weighed and manually fed into a rotatable perforated drum in a pressurizable chamber. The pressurizable chamber was isolated from the environment by a ball valve. The drum was rotated to start the coffee moving. Superheated steam at 16 bar and 300°C was metered into the pressurizable chamber. The pressure was selected to obtain a medium to dark roast color after both roasting steps without burning the beans. After 300 seconds, the flow of nitrogen into the pressurizable chamber was stopped and the pressure was quickly reduced to atmospheric pressure. The direction of the rotating drum was reversed, allowing the coffee to be metered into the outlet of the pressurizable chamber. The processed coffee was then collected through a valve assembly at the bottom of the pressurizable chamber.

[0080] 350 grams of roasted beans were placed in a perforated drawer under nitrogen pressure, which allowed exposure to a stream of hot air at the desired temperature. The temperature of the coffee beans was measured by a temperature probe. After 300 seconds at 210°C, the roasted coffee was transferred to a cooling chamber and exposed to a stream of ambient temperature, stopping the roasting process. Samples were then collected from the cooling chamber. The resulting coffees are referred to as NRefA (Arabica) and NRefB (Robusta).

[0081] Roasting in one step at atmospheric pressure: Further control samples were prepared as follows: 350 g of unextracted coffee was placed in a perforated drawer that could be exposed to a stream of hot air at the desired temperature. The temperature of the coffee beans was measured by a temperature probe. The roasting times for the Arabica and Robusta samples were adjusted to obtain similar roast colors: 360 seconds at 220°C for Arabica and 600 seconds at 220°C for Robusta. The roasted coffee was transferred to a cooling chamber and exposed to a stream of ambient temperature to stop the roasting process. The samples were then recovered from the cooling chamber. The Arabica sample is referred to as CRefA, and the Robusta sample is referred to as CRefB.

[0082] Example 6: Technical tasting: For tasting, roasted coffees were prepared in a filter coffee machine. 50 g of coffee was extracted with 1000 mL of water at a temperature of 100°C. Six individuals conducted the technical tasting. Each individual commented on the taste and aroma of each sample. All samples according to the invention (SA, SB, SEA, SEB, NEA, and NEB) were commented on a cereal note, whereas no cereal notes were commented on in the comparative examples. Rubbery, earthy notes were mentioned less frequently in the Robusta samples roasted according to the invention than in the comparative Robusta samples. SEB in particular was described as having a medium roast character and exhibited a balanced "coffeeness" profile, which is unusual for Robusta coffee.

[0083] Example 7: Aroma analysis After suspending roast and ground coffee (R&G) in water, the absolute content (mg / kg of roasted coffee) of aroma compounds of interest in the coffee was quantified by solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS / MS) with isotope-labeled standards. This isotope dilution analysis (also known as stable isotope dilution analysis) is a volatile analysis method that provides highly accurate measurements of compound content in roasted coffee. By adding labeled standards at the earliest possible stage of sample preparation, i.e., directly into the roast and ground coffee suspension, all physicochemical phenomena occurring between the addition of the standards and instrumental acquisition are fully compensated for.

[0084] Sample preparation A 5 g sample of roast and ground coffee was placed in a screw-cap flask, suspended in 100 mL of boiling water, capped, and stirred for 10 min. After cooling on ice, a defined amount of the labeled isotope of the analyte was added to the resulting slurry, and an aliquot (7 mL) of the sample was transferred to a sealed, silanized glass vial (a standard 20 mL vial used for headspace / SPME analysis).

[0085] Aroma extraction Samples were equilibrated at room temperature for 60 min. Aroma compounds were then extracted from the headspace by solid-phase microextraction (SPME) at 40 °C for 10 min (2 cm fiber, 50 / 30 μm StableFlex, coated with PDMS / DVB / Carboxen; Supelco, Buchs, Switzerland) and thermally desorbed onto a split-splitless injector (split mode, 2 splits) at 240 °C for 10 min. GC-MS / MS analysis of the compounds of interest was performed. Separation was performed using an Agilent 7890B gas chromatograph (Agilent, Basel, Switzerland) on a 60 m × 0.25 mm × 0.25 μm polar DB-624UI column (Agilent, Basel, Switzerland). Helium was used as the carrier gas at a constant flow rate of 1.2 mL / min. The following oven program was applied: initial temperature of 40 °C held for 6 min, then increased to 240 °C at 6 °C / min, and the final temperature held for 10 min. Mass analysis was performed on an Agilent 7010 Triple Quad mass spectrometer (Agilent, Basel, Switzerland). Chromatograms were run using Agilent MassHunter software.

[0086] Aroma Results Absolute content (mg / kg of roasted coffee) and ratios of aroma compounds of interest

[0087] [Table 1]

[0088] [Table 2]

[0089] All of the samples according to the present invention (SA, SB, SEA, SEB, NEA, and NEB) have a higher ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine than the comparative samples. Dimethyl disulfide is associated with a lightly roasted, cereal note, while alkylpyrazines, such as 2,3-diethyl-5-methylpyrazine, are associated with the earthy note characteristic of dark-roasted Robusta coffee. Thus, higher levels of dimethyl disulfide enhance the cereal note. All of the samples according to the present invention have lower levels of 2,3-diethyl-5-methylpyrazine than conventionally roasted coffees CRefA and CRefB. In particular, when the extracted green coffee is pressure-roasted with nitrogen gas in step a and then combined with an aqueous green coffee extract before roasting in step b (samples NEA and NEB), the roasted coffee has lower levels of 2,3-diethyl-5-methylpyrazine than comparative samples NRefA and NRefB.

[0090] The samples according to the invention (SA, SB, SEA, SEB, NEA, and NEB) all have a lower ratio of guaiacol to dimethyl disulfide than the comparative examples. Guaiacol is an aroma molecule associated with phenolic, medicinal, and smoky notes. These notes are generally associated with Robusta coffee characteristics and are generally considered undesirable. In particular, with regard to Robusta coffee, when the extracted green coffee is pressure-roasted with nitrogen or superheated steam in step a and then combined with the green coffee aqueous extract before roasting in step b (samples SEB and NEB), the roasted coffee is found to have much lower levels of guaiacol than the comparative examples SRefB, NRefB, and CRefB.

[0091] When extracted green coffee is pressure roasted with superheated steam in step a and then combined with an aqueous green coffee extract before roasting in step b (samples SEA and SEB), the roasted coffee is found to have a much higher dimethyl disulfide to methanethiol ratio than the comparative two-step roasted samples SRefA and SRefB or the conventionally roasted samples CRefA and CRefB. This is particularly evident in Robusta sample SEB, which had a dimethyl disulfide to methanethiol ratio more than three times higher than standard SRefB. A higher dimethyl disulfide to methanethiol ratio is associated with increased "coffee-ness" characteristics.

[0092] The Arabica samples according to the invention (SA, SEA, and NEA) all have a higher furfural to guaiacol ratio than the comparative Arabica samples (SREfA, NRefA, and CRefA). The Robusta samples according to the invention (SB, SEB, and NEB) all have a higher furfural to guaiacol ratio than the comparative Arabica samples (SRefB, NRefB, and CRefB). Guaiacol is an aroma molecule associated with phenolic, medicinal, and smoky notes. These notes are commonly associated with Robusta coffee characteristics and are generally considered undesirable. Increased furfural is positively associated with bready, lightly roasted, and sweet notes.

[0093] Example 8: Roast Color Roast Color: Roast color was determined by measuring the intensity of infrared (IR) light (904 nm) backscattered by the sample as measured on a Neuhaus Neotec ColorTest II® spectrophotometer.

[0094] [Table 3]

[0095] [Table 4]

Claims

1. 1. A method of roasting coffee, comprising: a. roasting extracted unroasted coffee at a pressure greater than 2 bar for 20 to 900 seconds, wherein the extracted unroasted coffee contains sucrose in an amount less than 80% of the amount of sucrose in an unextracted sample of the same coffee before roasting; b. Roasting the roasted, extracted coffee of step a. at a pressure of 0.5 bar to 1.5 bar and a coffee temperature of 180°C to 260°C for 20 to 1200 seconds.

2. 10. The method of claim 1, wherein the extracted unroasted coffee is obtained by extracting unroasted coffee with an aqueous liquid and then separating the extracted unroasted coffee from the extract.

3. 3. The method of claim 2, wherein the green coffee is not heated to a temperature greater than 110°C prior to extraction.

4. 4. The method of any one of claims 1 to 3, wherein the roasted extracted coffee of step a is combined with an aqueous extract of unroasted coffee before being roasted in step b.

5. 5. The method of claim 4, wherein the aqueous extract of green coffee is obtained by extracting green coffee with an aqueous liquid and then separating the extracted green coffee from the extract.

6. 6. The method according to any one of claims 1 to 5, wherein the extracted green coffee is roasted in step a) in the presence of superheated steam at a pressure higher than 9.5 bar.

7. 6. The method according to any one of claims 1 to 5, wherein the extracted green coffee is roasted in step a) in the presence of an inert gas.

8. Roasted coffee having a weight ratio of dimethyl disulfide to 2,3-diethyl-5-methylpyrazine greater than 4.

9. 9. Roasted coffee according to claim 8, wherein the weight ratio of guaiacol to dimethyl disulfide is less than 30.

10. Roasted coffee according to claim 8 or 9, wherein the weight ratio of dimethyl trisulfide to 2,3-diethyl-5-methylpyrazine is greater than 0.

6.

11. Roasted coffee according to any one of claims 8 to 10, wherein the weight ratio of dimethyl disulfide to methanethiol is greater than 1.

5.

12. Roasted coffee according to any one of claims 8 to 11, having a roast color of 30 to 100 CTN.

13. 10. Roasted coffee according to claim 8 or 9, which is packaged roasted coffee for further roasting.

14. The roasted coffee of claim 13, having a roast color of 75 to 160 CTN.

15. A container for use in a beverage preparation machine, the container containing roasted coffee according to any one of claims 8 to 12.

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