Method of processing a crushed vegetable material having a liquid and solid part

Abstract

A method for processing a crushed vegetal material, which has a solid part and liquid part and is placed inside a container, includes increasing the gas pressure inside the container so that the gas dissolves or diffuses in the liquid part; and decreasing the gas pressure inside the container.

Claims

1. A method for processing a previously crushed vegetal material, which has a solid part and liquid part and is placed inside a main container, said method comprising the steps of: (i) increasing the gas pressure inside the main container so that the gas dissolves or diffuses in said liquid part; and (ii) decreasing the gas pressure inside the main container by connecting the main container to the auxiliary container, so that gas previously diffused into the solid part reacts coming out of the solid part and bringing along fluid that stays in the solid part and interstices thereof; and (iii) collecting in the auxiliary container a liquid part expelled from the solid part together with the gas due to expulsion of the same gas caused by depressurization in the step (ii), wherein filters are interposed between the main container and the auxiliary container to retain the solid part but not the liquid part, such that the solid part is retained in the main container, and the liquid part is collected in the auxiliary container.

2. The method according to claim 1, wherein there is a waiting time (T.sub.att) between step (i) and step (ii).

3. The method according to claim 1, wherein in step (i) a gas is injected into the main container by making the gas enter into the lower part of the main container where in use there is the crushed vegetal material so that the gas dissolves in said liquid part.

4. The method according to claim 1, wherein the solid part is made to settle on the bottom of the main container and during step (i) the gas is injected inside said solid part.

5. The method according to claim 1, wherein steps (i) and (ii) follow each other in sequence cyclically.

6. The method according to claim 1, wherein step (i) is carried out by injecting a gas into the main container.

7. The method according to claim 1, wherein step (i) is carried out by injecting a gas at the bottom of the main container where in use there is the crushed vegetable material.

8. The method according to claim 1, wherein step (i) is carried out by migrating gas in/from an external inflatable bag connected to the main container.

9. The method according to claim 1, wherein step (i) is carried out by using a controlled connection with a second auxiliary container at a higher pressure.

10. A system, comprising: a main container for crushed vegetal material including a solid part and a liquid part; an auxiliary container connected to the main container; filters interposed between the main container and the auxiliary container to retain the solid part but not the liquid part; an electronic unit adapted to control a device configured to increase the gas pressure into the main container; and a device configured to decrease the gas pressure in the main container, wherein the electronic unit is configured to sequentially: drive the device configured to increase the gas pressure to obtain a gas pressure increase inside the main container so that the gas dissolves or diffuses in the liquid part; wait for a waiting time (Tatt); and drive the device configured to decrease the gas pressure to reduce the gas pressure inside the main container so that the gas dissolved in the liquid part returns in gas form.

11. The system according to claim 10, wherein the device configured to increase the gas pressure comprises an injector configured to inject a gas inside the lower part of the main container where in use there is present at least some solid part, so that the gas invests such solid part.

12. The system according to claim 10, wherein the device configured to increase the gas pressure comprises a valve adapted to let the internal volume of the main container communicate with the outside or not communicate with the outside.

13. The system according to claim 10, wherein the device configured to decrease the gas pressure in the main container comprises a communication fluid connection between the main container and an auxiliary container at an internal lower pressure.

14. The system according to claim 13, wherein the connection for fluid-communication is arranged between the lower part of the main container and the auxiliary container.

15. The system according to claim 13, wherein said filters comprise a sieve or grid filter or means for sieving, placed on the inner surface or bottom part of the main container in correspondence, in use, of said solid part and in communication with said connection and adapted to be passed-through by the liquid to let it get out of the container through the connection and retain the solid part.

16. The system according to claim 13, further comprising a valve configured to enable communication between the main container and the auxiliary container.

17. The method according to claim 1, wherein the step (i) is carried out by mechanically varying the volume of the main container.

Description

(1) The advantages of the invention will be more apparent from the following description of a preferred embodiment, by reference to annexed drawing in which

(2) FIG. 1 shows a front view of a fermenter apparatus capable of implementing the method,

(3) FIG. 2 shows a front view of the apparatus of FIG. 1 in different configuration (transfer phase for pressurized delestage);

(4) FIG. 3 shows a front view of a variant of the apparatus (phase of draining must);

(5) FIG. 4 shows a front view of a second variant of apparatus;

(6) FIGS. 5, 6, 7, and 8 show sectional views of successive steps of the draining process for the must;

(7) FIG. 9-10 show a front view of a third variant of apparatus;

(8) FIG. 11 shows a front view of a fourth variant of apparatus.

(9) In the description and in the various drawings the same references indicate equal parts. So the parts indicated by the same number, but for brevity not every time described, share the same description.

(10) A system of fermentation MC (FIG. 1) comprises a main fermentation tank 10, which contains must which by fermenting has generated a marc cap 16.

(11) The tank 10 is equipped with a pressure sensor 30 and a gas-pressure regulating valve 32 (near an upper hatch). The valve 32 serves both to open/close the upper part of the tank 10 (for depressurizing it), and to finely adjust the internal pressure. It is more advantageous to use two different valves: one for the depressurization and one for fine adjustment of the pressure, to adjust with greater precision the pressure inside the tank because the needs of a rapid depressurization and of a fine-adjustment require different valves. For the depressurization it can be arranged a valve with passage section of at least 20 mm in diameter, while for the pressure regulation the use of a valve having a maximum passage section of 10 mm in diameter.

(12) The lower walls and/or the bottom of the tank 10 comprise a grilled belt or draining sectors 80 capable of letting liquid to pass but retaining macroscopic solid parts (see FIGS. 5-8). The sectors 80 comprise a interspace 82 in which the filtered liquid can accumulate.

(13) Valves 34, 36 can selectively put into communication the sectors 80 with, respectively, a first-must storage tank 40 and a draining tank 50 through a draining pipe 35. At the bottom of the tank 10 one or more nozzles 62 for gas injection open, said gas coming from controlled gas delivery means 66 for gas taken and/or mixed selectively from cylinders and reserves 68. Preferably the nozzles 62 lead into approximately the center of the tank 10 or on an inner radius far from the side walls.

(14) A PLC or processing unit 60 is interfaced with the sensor 30, the valves 32, 34, 36, the nozzles 62 and the means 66, in order to control them in general, and in particular to detect data therefrom and monitor the opening/closing state or activity thereof. Note that the valves 34, 36 may be manual, and that the finely pressure-regulating valve may also be of mechanical type.

(15) Phases of Operation

(16) (here and in the following the actions carried out by the components are advantageously meant to be driven by unit 60, but also a manual intervention is possible).

(17) 1) The tank 10 is filled with crushed grapes, which has formed a floating marc cap 16 on a liquid part 14 (FIG. 1). If the alcoholic fermentation is not started, the mass of must and peel is mixed without a marc cap. The invention operates in both cases, and also when fermentation is finished.

(18) 2) If the first juice is not already extracted, one can optionally exploit a pressurization of the tank 10 as a method of first draining towards the tank 40 (FIG. 2).

(19) The pressure in the tank 10 is increased by selecting which gas to use among the cylinders 68 and by injecting gas from means 66, or if the mass of crushed material is under alcoholic fermentation, one can use the CO.sub.2 generated by fermentation as a pressurization gas. When the pressure in the tank 10 has reached a programmed value the valve 36 is opened and the juice flows into tank 40 (see arrow F1 in FIG. 2). One can set in the unit 60 a range or threshold pressure below which the valve 34 closes and above which it opens. If one uses an external gas, the gas injection is through the pipe or nozzles 62 immersed in the crushed material, and this will facilitate the dissolution of the gas in the liquid part, very useful in the next step.

(20) The program of unit 60 may provide for a maximum time of draining T.sub.MS of the juice, or one can insert a probe into the tank 10 that indicates the achievement of a minimum level of liquid, below which cycles of pressurized draining of the marc 16 (phase 3) begin.

(21) Or one can apply to the valve 36 a flow sensor that signals the moment when the juice is completely drained.

(22) In any case, when almost all of the liquid is removed, the marc or solid part 16 accumulates on the bottom of the tank 10 (FIG. 3).

(23) Note that regardless of the method of primary draining for the first juice (must), by using e.g. pressurization of the empty bottom part of the tank 10 (the pressurized gas behaves as a mechanical piston) or by pressurization of one or more internal membranes to the tank or to the press or, finally, by gravity and/or by using a pump, at a certain point the marc 16 laid on the bottom will not release more juice. The pressure of the gas on the marc 16 deposited on the bottom, or its own weight, or the mechanical pressure of said membrane, compact it transforming it into a sort of plug that prevents the outflow of the residual must. The wet skins, adhering to the walls of the sectors 80, plug the holes thereof.

(24) Experimental tests have shown that when the cap 16 is lying on the bottom a further increase of the internal pressure does not cause any drainage of the residual must. Even continuous depressurization of pipe 35 does not determine, beyond a certain point, any drain of the residual must. Indeed, as for the known pressing membranes, after draining the part of must present in the skin adjacent to the internal draining sector 80, the marc ends up compacted on the surface of the sectors 80, hindering further drainage and leaving a substantial amount of juice inside the grape skins.

(25) 3) the pressure in the tank 10 is increased (FIG. 3), which tank is pressurized with a gas selected by the unit 60 and put in by the nozzles 62 (see arrow F2). The gas is preferably inert and highly dissolvable in the residual liquid part due to the pressure. Gas suitable for the purpose are e.g. CO.sub.2 or nitrogen.

(26) The pressure inside the tank 10 in case of maceration by saturation is preferably brought to values between 0.2 and 2 bar, typically related to the consistency of the skins contained in the must to be macerated.

(27) The pressure inside the tank 10 in case of pressing by saturation is preferably brought to values between 0.2 and 6 bar, generally related to the amount of liquid to be extracted, or to the degree the marc 16 is to be dehydrated.

(28) It is advisable, if one wants to achieve a high level of dehydration for the marc 16, to proceed at various levels of increasing pressure, e.g. with series of cycles at 0.5 bar, series of cycles at 1 bar, series of cycles at 1.5 bar, etc.

(29) It is good that the injection of gas takes place in the lower part of the tank 10 and in any case in the internal mass of the marc/liquid 16. To the purpose it is preferable to use multiple nozzles 62, e.g. two to ten, so as to better distribute the gas within the mass of wet marc.

(30) The pressurization with resulting saturation, with or without a successive period of inactivity, can last e.g. 60 seconds to 12 hours (in relation to the type of grape or grape marc 16).

(31) 4) during the maceration by saturation the valve 32 is opened after waiting for a time unit T.sub.att from when pressure has reached saturation pressure P.sub.S set inside the tank 10. This causes the transformation of a limited quantity (proportional to: the density of the must, type of gas used, pressure P.sub.S, saturation time and amplitude of the pressure reduction) of liquid gas saturated in the must in the form of gas microbubbles. The generated gas has a gentle erosive effect on the soft part of the peel and a capillary upwards dragging, i.e. towards the outside of the tank 10, of residual oxygen in the mass. Then the injection of gas proceeds up to attaining the value of the initial pressure P.sub.S (e.g. 400 mbar), a time T.sub.att is waited for, then the valve 32 is opened until the pressure drops by a certain decrement P, e.g. of 50 mbar, then the pressure is restored by injection into the crushed material of saturation gas going back to the P.sub.S value. During pressing by saturation the planned cyclic opening of valve(s) 34 occurs, resulting in depressurization of the interspace 82 and spilling of must toward the tank 50 (see arrow F3 and FIG. 6). This must is both the one dripped inside the interspace 82, and the one expelled from the marc 16 adjacent to the sector 80 due to transformation of gas, previously dissolved into the must, into free gaseous state (see arrow F4).

(32) The sudden transformation of gas from liquid into gaseous state, that takes place in layers of the marc 16 adjacent to the sectors 80, ejects and sucks up the liquid part that meets on its way toward the valve 34. The drainage effect is intensified by the fact that the gas, passing abruptly from liquid to gaseous state, increases in volume, therefore on the one hand it opens the marc 16, preventing that this compacts and thereby favoring the drainage, on the other it erodes only the residual part of liquid and pulp present in the marc 16 and conveys it to the outside.

(33) The valve opening 34 can last e.g. 30 seconds to 30 minutes, its closure e.g. 60 seconds to 30 minutes in relation to the time of gas saturation in the liquid remaining in the marc 16 adjacent to the draining sectors 80.

(34) Then the valve 34 is closed (FIG. 7) and opened again (FIG. 8), for a number of cycles, which can go e.g. from 10 to 50.

(35) Because of the opening of the marc 16, in turn caused by the sudden transformation of the gas dissolved in the must due to the differential between internal pressure of the marc cap 16 and pressure of the tank 50, cycle by cycle the must inside the grape marc 16 will flow to the interspace 82 and from there it will be expelled to, and collected in, the tank 50. Time after time the must will migrate from the center to the periphery of the marc 16, where there are the sectors 80, and a dry zone 85 of marc expands towards the center. In particular: when the valve 34 is closed again (FIG. 7), in the layers of marc 16 adjacent to the sector 80, now emptied and divaricated, the accumulation of new must rich of liquid gas begins. This must also will invade again the interspace 82 (arrow F5); by re-opening the valve 34 (FIG. 8) one expels the must contained in the interspace 82 plus that sucked up (see arrow F6) by the depressurization of the adjacent layers 85 of marc 16.

(36) The number of cycles being equal, the efficiency of drainage can be increased by increasing the pressure in the tank 10 or by decreasing that in the tank 50, e.g. by providing it with a vacuum pump.

(37) The tank 50 can also be used as a relaunch-tank of the drained must toward another tank 99 (FIG. 4). It is enough to pressurize the tank 50 with inert gas and provide it with a pressure-adjustment valve 98, a pressure sensor 97, a point of injection of gas coming from a mixer/dispenser 93 and a further drain valve 95, the whole connected to the unit 60 for the control, or to another electronic unit. The operation is the same as described for the tanks 10, 50.

(38) To increase the efficiency of the sectors 80 it is advantageous that they are positioned circumferentially on the bottom of the tank 10 (in the case of a press or a horizontal tank the sectors may be longitudinal or internal to the container itself) and/or they are structured as draining septa movable in a controlled manner inside the tank 10 and able to spread apart the marc (e.g. mounted on or constituting a scraping blade rotatably mounted on the bottom of the tank 10); they have a total area greater than: 0.5 m.sup.2 per 100 hl of capacity of the tank 10 where the latter is a fermentation or maceration tank loaded with crushed material; or 2 m.sup.2 every 100 hl of capacity of the tank 10 where the latter is a press for marc. they have a perforated surface (which acts as a separator between the skin and the liquid part) of at least 30% compared to the total, with a size of the holes such as to prevent the passage of the peel.

(39) The above mentioned parameters for the sector 80 define the optimal surface of pressurized drainage of the marc 16 as shown by experimental tests.

(40) In the example of FIG. 1-2 the two tanks 50, 40 are open and distinct. One may use however two closed tanks equipped with appropriate valves for adjusting pressure and gas injection, and one might use a single tank for receiving must.

(41) FIGS. 9-10 show an apparatus MC2 which has substantially the same structure of FIG. 1 and is working for the maceration of a crushed material 14 placed in the tank 10.

(42) Operation

(43) Phase a: The unit 60 injects (FIG. 9, see arrow W2) in the mass of crushed grapes 14 some gas taken/mixed from reserves 68 through the pipe 62. The resulting pressurization of the tank 10 determines the saturation of the mass of crushed material 14 with the gas dissolved and released in it (Henry's law). The amount of injected gas can be controlled for its flow rate or by the sensor 30.

(44) Phase b: (optional) a certain time is waited for to ensure the saturation of the mass of crushed grapes 14 by the gas.

(45) Phase c: (FIG. 10) the valve 32 is opened causing a depression in the tank 10, and thus a gas flow (see arrow W3) toward the outside. The drop of pressure returns the dissolved gas to a gaseous state, which gas thus comes out from the liquid (arrows W4). The microbubbles of gas rising in the mass of crushed grapes 35 aggregate oxygen molecules and drag them outside of the tank 10.

(46) Repeated for n cycles the phases a-b-c one will come to a complete deoxidation of the crushed grapes 14.

(47) FIG. 11 presents an apparatus MC3 which has substantially the same operation of the one in FIGS. 1-8 but takes advantage of the inventive principle by applying it on a known press 10p, e.g. equipped with a drum 11p having rotating horizontal axis X provided with known draining sectors 80p and a valve 36p for loading must controlled by the unit 60. The press 10p can have or not an inner inflatable membrane. Essentially, the press 10p may replace the tank 10 in each variant described above, while the components external to the press 10p are the same of the previous figures.

(48) Without repeating the steps of operation, which is the same, just note that the press 10p can be the location of the illustrated maceration and/or pressing method.