Method for reconditioning a wooden container comprising a tannic and / or aromatic impregnation step for impregnating the wooden container

Abstract

The invention relates to a method for reconditioning a wooden container (10), the method comprising: - a step of renewing the inner surface (12) of the wooden container (10) consisting in removing a layer of wood from the inner surface thereof (12) in order to restore the porosity of the wood of the container on the inner surface (12); - a step of tannic and / or aromatic impregnation by at least partially filling the wooden container (10) with a solution (16) comprising at least one wood-based tannic and / or aromatic extract and letting the wooden container (10) absorb at least some of the solution (16) via the inner surface (12). The impregnation step enables specific organoleptic properties to be returned to the wooden container, thereby allowing it to be used for maturing a wine or ageing a spirit.

Description

[0001] Method for reconditioning a wooden container comprising a step of tannic and / or aromatic impregnation of the wooden container

[0002] The present application relates to a method for reconditioning a wooden container comprising a step of tannic and / or aromatic impregnation of the wooden container.

[0003] Some wines are aged in wooden containers to achieve gradual oxygenation through the wooden containers as well as a transfer of aromas and tannins between the wine and the wood of the container.

[0004] For the purposes of this application, a wooden container means a barrel, cask, barrel or other container used for maturing wine or aging a spirit.

[0005] Gradually, after containing one or more wines, the interior of the wooden container is altered on the surface, to a depth of a few millimeters, by micro-organisms and by an accumulation of organic and / or mineral deposits. This accumulation gradually blocks the pores of the wood, leading to a reduction or even total elimination of gas exchange between the wine and the exterior of the wooden container and totally or partially preventing the wood from releasing into the wine various substances it contains, such as aromas or tannins.

[0006] Various techniques have been developed to regenerate wooden containers. One technique involves planing the entire interior surface of the wooden container to obtain new wood, then heating the wooden container to give it aromatic characteristics. Another technique, described in document EP2012971, involves projecting an abrasive against the interior surface of the wooden container to remove the damaged layer of wood.

[0007] Generally, a wooden container such as a barrel is used to age 2 to 3 wines, or for 5 to 6 years, and must then be regenerated.

[0008] Although these solutions allow the initial characteristics of the wooden container to be restored regarding gas exchanges between the wine and the exterior of the wooden container, they do not allow the initial characteristics of the aromas and tannins to be restored. Given these losses, the aging of certain wines can only be carried out in new wooden containers or those used for the aging of a single wine. Since a 150-year-old oak tree is needed to produce 5 to 7 barrels, there is a risk of depletion of the resource.

[0009] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0010] For this purpose, the invention relates to a method for reconditioning a wooden container made of a given wood species and having an interior surface. This method comprises: a step of regenerating the interior surface of the wooden container consisting of removing a layer of wood at its interior surface to restore the porosity of the wood of the container at the interior surface, a step of tannic and / or aromatic impregnation by filling, at least partially, the wooden container with a solution containing at least one aromatic and / or tannic extract based on wood and allowing the wood of the wooden container to absorb, via the interior surface, at least part of the solution.

[0011] This impregnation step restores specific organoleptic properties to the wooden container, allowing it to be used for aging wine or spirits. The reconditioning process allows the barrels to be used for 10 to 15 years instead of 5 to 6 years, which reduces the risk of resource depletion.

[0012] According to other characteristics taken individually or in combination: the aromatic and / or tannic extract based on wood is obtained from pieces of wood having the same species as the wooden container; the impregnation step comprises a phase of pressurizing the interior of the wooden container to a reference pressure higher than atmospheric pressure, the reference pressure being a relative pressure of between 0.3 and 3 bars; the solution has a tannin content of between 20 and 100 g / l and / or a vanillin content of between 100 and 230 mg / l; the impregnation step has a duration of between 7 and 20 days.the solution introduced into the wooden container has a volume of between 2% and 30% of the volume of the wooden container, the wooden container being set in motion so that the solution is, alternately, in contact with all or almost all of the interior surface; the reconditioning method comprises, after the impregnation step, a step of diffusion of hot air pulsed inside the wooden container.

[0013] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which:

[0014] Figure 1 is a cross-section of a wooden container illustrating a step of tannic and / or aromatic impregnation of the wooden container according to the invention, Figure 2 is a longitudinal section of a device for tannic and / or aromatic impregnation of a wooden container illustrating an embodiment of the invention.

[0015] In Figures 1 and 2, a wooden container, in particular oak wood, for maturing a wine or aging a spirit is shown at 10.

[0016] This wooden container 10 comprises a body 10.1 which has an axis of revolution A10 and which is closed at each end by bottoms 10.2, 10.3. This wooden container 10 is made from assembled and strapped staves.

[0017] In one configuration, the wood is French oak. Of course, the invention is not limited to this species. For example, the wood species used are oak species of different origins (France, United States, Eastern European countries, South America, etc.), acacia, amburana, etc.

[0018] According to one method, once felled, the trees are split into staves which are dried for several years (around 3 years) in order to extract the most bitter tannins. The staves are then cut into staves which are assembled to form the body 10.1 and the bases 10.2, 10.3 of a wooden container 10.

[0019] After its assembly, the wooden container 10 comprises an interior surface 12 as well as at least one orifice 14, called a bung hole, allowing communication between the interior and the exterior of the wooden container 10.

[0020] After its assembly, the inner surface 12 of the wooden container 10 is heated in order to give the wooden container 10 given organoleptic properties, in particular in terms of aromas and tannins. For information purposes, this initial heating, also called wood-burning, affects the wood over a thickness of a few millimeters, of the order of 5 millimeters. At the end of the heating step, the wooden container 10, made of a given wood species, has an initial state (in particular in terms of health and porosity) as well as initial organoleptic properties.

[0021] The process for manufacturing a wooden container is not further described because it is known to those skilled in the art.

[0022] The wooden container can have different capacities (from 80 to 600 liters) and can be used to store wine, spirits or beer.

[0023] After the aging of one or more wines, the interior surface 12 of the wooden container 10 is altered.

[0024] The method for reconditioning a wooden container 10 comprises a step of regenerating the interior surface 12 of the wooden container 10 to restore the porosity of the wood of the container at the interior surface 12 in order to restore the wooden container 10 to a state close to or identical to the initial state.

[0025] According to one procedure, the method described in document EP2012971 is used for the regeneration step. Of course, the invention is not limited to this procedure. Thus, the wooden container 10 can be regenerated by planing it in order to remove a layer of wood at its inner surface 12 and by subjecting this inner surface 12 to a new heating or by using ultrasound for example.

[0026] After this regeneration step, the reconditioning process may or may not include a step of heating the interior surface 12 of the regenerated wooden container 10.

[0027] According to an essential characteristic of the invention, the reconditioning method comprises a tannic and / or aromatic impregnation step by filling, at least partially, the wooden container 10 with a solution 16 containing at least one aromatic and / or tannic extract based on wood and by allowing the wood of the wooden container to absorb, via the interior surface 12, at least part of the solution 16. This impregnation step makes it possible to restore specific organoleptic properties to the wooden container 10.

[0028] According to one embodiment, solution 16 is an aqueous solution or composition.

[0029] In one configuration, the aromatic and / or tannic extract based on wood is in the form of a powder.

[0030] According to one procedure, the aromatic and / or tannic extract powder is obtained from a process which comprises a step of heating at least one piece of dried raw wood, an aqueous extraction step in order to obtain a solution containing components extracted from the wood and a step of atomizing said solution in order to obtain the wood-based aromatic and / or tannic extract powder. This process for obtaining wood-based aromatic and / or tannic extract is described in particular in document WO2016169428.

[0031] Of course, the invention is not limited to this procedure for obtaining the aromatic and / or tannic extract based on wood. Different extraction techniques can be used to obtain this extract. It can be in the form of a powder or a solution (liquid).

[0032] According to one feature, the aromatic and / or tannic extract based on wood is obtained from pieces of wood having the same species as the wooden container 10. Thus, the impregnation step makes it possible to restore to the wooden container 10 organoleptic properties close to or identical to the initial organoleptic properties of the wooden container after heating.

[0033] For example, if the wooden container 10 is made from raw sessile oak wood (Quercus Petrae L), the aromatic and / or tannic extract is produced from the same species.

[0034] According to one embodiment, the wood-based aromatic and / or tannic extract is obtained from pieces of wood having the same species as the wooden container 10 but also the same grain.

[0035] According to one operating method, the pieces of wood used to obtain the aromatic and / or tannic extract come from cutting pieces of wood (staves, staves) from wooden containers 10 of the same species. This solution is a way of recovering waste from the manufacture of wooden containers 10.

[0036] According to another characteristic, solution 16 has a tannin content of between 20 and 100 g / l. Preferably, solution 16 has a vanillin content of between 100 and 230 mg / l.

[0037] According to one operating mode, the solution 16 comprising at least one aromatic and / or tannic extract based on wood, introduced into the wooden container 10, has a volume of between 2% and 30% of the volume of the wooden container 10. For example, in the case of a barrel with a capacity of the order of 225 I, the volume of the solution 16 introduced into the barrel is between 5 and 30 I. Preferably, this volume is between 6 and 9 I.

[0038] The impregnation step has a duration of between 7 and 20 days depending essentially on the nature of the wood (species, grain, porosity, etc.). When the solution 16 is not simultaneously in contact with the entire interior surface 12, the impregnation step comprises moving the wooden container 10 so that the solution 16 is alternately in contact with all or almost all of the interior surface 12. According to one operating mode, the wooden container 10 is rotated around its axis A10, as illustrated in FIG. 2.

[0039] The rotation of the wooden container 10 may be continuous and slow, a complete revolution of the wooden container 10 being performed in a duration of between 5 and 20 min. Alternatively, the rotation of the wooden container 10 is discontinuous, the wooden container 10 performing rotations of a given angular value, for example from 45 to 60°, separated by static periods for a duration of between 10 and 60 min. Whatever the operating mode, the rotation of the wooden container 10 must make it possible to bring all the points of the inner surface 12 of the body 10.1 into contact with the solution 16 for substantially the same duration. According to one embodiment, a device for implementing the method of the invention is configured to rotate at least one wooden container 10.As illustrated in Figure 2, the device comprises a support 18, configured to support an approximately horizontal wooden container 10 (axis of revolution A10 approximately horizontal) as well as two pairs of rollers 20 positioned symmetrically on either side of a vertical median plane passing through the axis of revolution A10, each pair of rollers 20 comprising a first roller close to the first bottom 10.2 and a second roller close to the second bottom 10.3, at least one of the rollers being coupled to a motor 22 to drive it in rotation. Thus, the rotation of at least one roller 20 generates by friction the rotation of the wooden container 10 around its axis of revolution A10. Of course, the invention is not limited to this device for rotating the wooden container.

[0040] During the impregnation step, the solution 16 is at least partially absorbed by the wood of the wooden container 10. According to one procedure, all of the solution 16 is absorbed by the wood of the wooden container 10.

[0041] To increase the effectiveness of the impregnation, the impregnation step comprises a phase of pressurizing the interior of the wooden container 10 to a reference pressure higher than atmospheric pressure. According to one operating mode, the pressurizing phase has a duration substantially equal to the duration of the impregnation step. According to one configuration, the interior of the wooden container 10 is subjected to a substantially constant reference pressure during at least part of the impregnation step and, optionally, for the entire duration of the impregnation step. The reference pressure is a relative pressure of between 0.3 and 3 bar. According to one configuration, the reference pressure is between 0.6 and 0.9 bar.

[0042] According to one embodiment, the wooden container 10 contains, in addition to the solution 16, a supply gas during the impregnation step and the pressurization of the interior of the wooden container 10. According to one configuration, the supply gas is a mixture of air and ozone.

[0043] The device for implementing the method of the invention comprises a plug 24 configured to close the orifice 14 and maintain a constant pressure in the wooden container 10, substantially equal to the reference pressure. This plug 24 is equipped with a sensor for measuring the pressure inside the wooden container 10 as well as a valve connected to a supply 26 of supply gas and configured to occupy a closed state when the pressure inside the wooden container 10 measured by the sensor is greater than or equal to the reference pressure and a passing state when the pressure inside the wooden container measured by the sensor is lower than the reference pressure. Of course, the invention is not limited to this embodiment for maintaining a substantially constant pressure inside the wooden container for the duration of the impregnation phase.

[0044] At the end of the impregnation step, the quantity of dry matter of the aromatic and / or tannic extracts impregnated in the wood of the wooden container 10 is between 1 and 5 kg. Preferably, this quantity is of the order of 1.5 kg.

[0045] According to one operating mode, after the impregnation step, the reconditioning method comprises a step of diffusion of hot air pulsed inside the wooden container, via the orifice 14, in order to reinforce the fixation of the aromatic and / or tannic extracts in the wood of the wooden container 10. The hot air pulsed has a temperature of between 200 and 500°C, preferably of the order of 400°C.

Claims

DEMANDS 1. A method for reconditioning a wooden container (10) made of a given wood species and having an inner surface (12), said method comprising a step of regenerating the inner surface (12) of the wooden container (10) consisting of removing a layer of wood at the level of its inner surface (12) to restore the porosity of the wood of the container at the level of the inner surface (12), characterized in that the reconditioning method comprises a step of tannic and / or aromatic impregnation by filling at least partially the wooden container (10) with a solution (16) containing at least one aromatic and / or tannic extract based on wood and allowing the wood of the wooden container (10) to absorb, via the inner surface (12), at least a part of the solution (16).

2. A method for reconditioning a wooden container (10) according to claim 1, characterized in that the aromatic and / or tannic wood-based extract is obtained from pieces of wood having the same essence as the wooden container (10).

3. Method for reconditioning a wooden container (10) according to any one of the preceding claims, characterized in that the impregnation step includes a phase of pressurizing the inside of the wooden container (10) to a reference pressure greater than atmospheric pressure.

4. Method for reconditioning a wooden container (10) according to the preceding claim, characterized in that the reference pressure is a relative pressure between 0.3 and 3 bars.

5. Method for reconditioning a wooden container (10) according to claim 3 or 4, characterized in that the wooden container (10) contains, in addition to the solution (16), a mixture of air and ozone during the impregnation step and the pressurization of the inside of the wooden container (10).

6. Method for reconditioning a wooden container (10) according to any one of the preceding claims, characterized in that the solution (16) has a tannin content of between 20 and 100 g / l and / or a vanillin content of between 100 and 230 mg / l.

7. Method for reconditioning a wooden container (10) according to any one of the preceding claims, characterized in that the impregnation step has a duration of between 7 and 20 days.

8. Method for reconditioning a wooden container (10) according to any one of the preceding claims, characterized in that the solution (16) introduced into the wooden container (10) has a volume between 2% and 30% of the volume of the wooden container (10).

9. Method for reconditioning a wooden container (10) according to the preceding claim, characterized in that during the impregnation step, the wooden container (10) is set in motion so that the solution (16) is alternately in contact with all or almost all of the inner surface (12).

10. Method for reconditioning a wooden container (10) according to any one of the preceding claims, characterized in that it comprises, after the impregnation step, a step of diffusing pulsed hot air inside the wooden container.

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