PROCESS AND APPARATUS TO COMBINE HEAT-ASSISTED MACERATION AND SELF-ENRICHMENT IN THE PRODUCTION OF RED AND ROSE WINES.

Abstract: Process and apparatus for the treatment of pressed grapes comprising in a sequence a phase of heat-assisted maceration of the pressed grapes (A) to extract the desired substances from the solid parts of the grapes, a phase of draining to remove the solid parts from the pressed grapes (A) so as to thereby obtain the must (B), and a phase of partial evaporation of the water contained in the must to increase the concentration of sugars therein. The evaporation phase takes place in two stages at two different temperatures (tc0, tc2), and the latent heat of the vapour (C) obtained from the must (B) in the stage at a higher temperature (tc0) is used to bring the pressed grapes (A) up to an intermediate temperature (tA1) between the inlet temperature (tA0) and the temperature (tAM) required by the maceration phase.

Description: PROCESS AND APPARATUS TO COMBINE HEAT-ASSISTED MACERATION AND SELF-ENRICHMENT IN THE PRODUCTION OF RED AND ROSE WINES DESCRIPTION The present invention refers to a process for combining heat-assisted maceration and self-enrichment in the production of red and rose wines, as well as an apparatus for carrying out such a process. Quality-related issues are becoming of an increasingly significant importance also in the wine-making industry and trade due to the quality awareness of an increasing number of consumers. In particular, consumers expect red and rose wines to be, from an organoleptic point of view, full-bodied, i. e. to have a good substance, an appropriate colour and an alcoholic strength meeting the requirements of the standard regulations. It is generally known that, among such qualities of wine, body and colour originate from the solid parts of the grapes, in particular from the skin and the pulp, which are therefore allowed to remain with the must for a more or less long period of time in view of allowing them to undergo maceration. Maceration can take place in a natural manner at ambient temperature, in which case the process has usually a duration that may even extend to cover several days, as necessary in view of obtaining the required extraction of the desired substances. According to a recently introduced, but increasingly valued and accepted practice, such a maceration process is also carried out at a temperature ranging between approx. 60 and 80°C through the supply of heat by a suitable energy source. In this particular case, the process itself is commonly referred to as heat-assisted maceration and has the advantage of having, for the same results obtained in terms of quality, a much shorter duration, generally in the order of 1 to 1.5 hours. As far as the possibility is concerned of obtaining a good alcoholic degree, i. e. the strength of the wine, instead of adding sugars or blending the must with grapes of a higher sugar content, use is being made since a few years of a new practice, which is generally referred to as self-enrichment in the art and consists in removing a given proportion of the water contained in the must so as to increase the concentration of sugar. This phase, which requires the pressed grapes to be drained so as to have only the must actually involved in it, follows the heat-assisted maceration one and, most obviously, precedes the alcoholic fermentation phase, where the must itself is actually converted into wine, which actually takes place under controlled temperature conditions of approximately 19 to 23 °C. The said phases of heat-assisted maceration of the pressed grapes and self- enrichment of the must, which require process temperatures in excess of the ambient temperature, are carried out in separate equipments, which unavoidably entails a cooling down between the former and the latter phase, further to the necessary final cooling down preceding the alcoholic fermentation phase. As a consequence a large amount of heat energy is required by the overall process that affects the industrial costs in the production of red and rose wines to a significant extent. It therefore would be desirable, and it is actually a main object of the present invention, to reduce such a usage of heat energy in the production of red and rose wines, while of course preserving, and possibly even enhancing, their above cited organoleptic qualities. An industrial process combining the phases of heat-assisted maceration and self- enrichment is therefore a first subj ect of this patent. An apparatus combining both heat-assisted maceration and self-enrichment equipments is accordingly a second subject of the present invention. The features and characteristics of the present invention, as recited in the appended claims, will be more readily understood, along with the advantages thereof, from the description that is given below by way of a non-limiting example of an apparatus. The accompanying drawing illustrates a layout of the apparatus and, for reasons of greater clearness and simplicity, is intentionally limited to those sole parts which are directly relevant to the purposes of the present invention. As this will be explained in greater detail further on, reference is made in the following description to four process media which, for reasons of greater simplicity, are designated as follows: — A is used to indicate the pressed grapes, inclusive of all solid parts of the same grapes (i. e. skin, pulp, grape-stones); - B is used to indicate the must which is obtained from the removal from the pressed grapes (medium A) of all of the above-mentioned solid parts through a draining operation; — C is used to indicate the water vapour extracted from the must (medium B); — D is used to indicate steam as produced from water by a steam generator; - E is used to indicate a coolant or refrigerant medium; — F is used to indicate the air that is removed in view of keeping some parts of the apparatus in a state of negative pressure, i. e. at a pressure below the atmospheric one As illustrated in the accompanying drawing, an apparatus according to the present invention for the production of red and rose wines comprises following main parts: - a first tank 10, with an inlet pipe 11 for letting in the medium A coming from the grape pressing machinery (not shown) and an outlet pipe 12 connected to a delivery pump 13. A stirrer 14, whose driving motor 15 is arranged on top of the tank 10, prevents the solid parts contained in the medium A from separating in a natural manner from the liquid to come afloat to the surface of the liquid; - a first heat exchanger 20, in which the media A and B are heated up by the medium C, wherein such a heat exchanger comprises: • a plurality of vertical tubes 21 for the medium B to flow therethrough, provided with an upper inlet manifold 22 and a lower outlet manifold 23 ; . • a coil 24 for the medium A to flow therethrough, with a lower inlet 25 coming from the tank 10 via a piping 16 connected to the pump 13, and an upper outlet 26; • an upper inlet 27 and a lower outlet 28, the latter being directly connected to a phase separator 29, for the medium C circulating between the various vertical tubes 21 ; — a second heat exchanger 30, at least conceptually similar to said first heat exchanger 20, which comprises : • a plurality of vertical tubes 31 for the medium B to flow therethrough, provided with an upper inlet manifold 32 and a lower outlet manifold 33 ; • a coil 34 for the medium A to flow therethrough, with a lower inlet 35 connected with the upper outlet 26 of said coil 24, and an upper outlet 36; • an upper inlet 37, connected to a steam generator (not shown) for the medium D in the form of superheated vapour, and a lower outlet 38 for the condensate liquid of the same medium D; - a first evaporation vessel 40 (generally known in the art under the French wording "boule") for the evaporation of the water contained in the medium B, with: • a conduit 41 coming from the outlet manifold 33 of the second heat exchanger 30; • a lower mouth 42 directly connected with the top portion of a second tank 50 which is described below, for the introduction of the medium B; • an upper mouth 43 connected by means of a piping 44 to the afore mentioned inlet 27 of the medium C into the first heat exchanger 20; - a second tank 50 (acting as a dwelling reservoir), on the top portion 51 of which there is provided the above mentioned mouth 42 for connection to the first evaporation vessel 40, with: • a filter 52 for the separation of the solid parts of the medium A (pressed grapes) so as to obtain the medium B (must); • a first lower mouth 53, provided downstream of the filter 52, for transferring the same medium B all along up to the inlet manifold 32 of the second heat exchanger 30 by means of a pump 54 and along a conduit .55; • the inlet 56, which is also provided on the top portion 51 , but at a distance from the mouth 42, for the medium A flowing in from the outlet 36 of said coil 34; • an outlet conduit 57 for the same medium A, which starts off the bottom of the tank 50, upstream of the filter 52; • a stirrer 58, the driving motor 59 of which is arranged on the top portion 51, for ensuring a continuous stirring of the medium A inside the filter 52; - a second evaporation vessel ("boule") 60 with: • a filter 61 for the separation of the residual solid parts of the medium A (pressed grapes) so as to obtain the medium B (must); • an inlet mouth 62 for the medium A, provided at the terminal portion of the afore mentioned outlet piping 57 of the second tank 50, upstream of the. filter 61 ; • an outlet mouth 63 for the medium B, which is situated below, i. e. downstream of the same filter 61, and is connected with the inlet manifold 22 of the first heat exchanger 20 via a pump ,64 and a conduit 65; • an inlet mouth 67 for the same medium B flowing in from the outlet manifold 23 of the first heat exchanger 20, i which said mouth 67 is provided above said inlet mouth 62 for the medium A; • an outlet mouth 68, provided on the top portion 69 of the second evaporation vessel 60, for transferring the medium C up to a third heat exchanger 70, which is described below; • an outlet piping 85 for the medium A,- which starts off the lowest point of the same evaporation vessel 60, upstream of the filter 61, and reaches up to a fourth heat exchanger 90 (described further on) via a pump 86; - a third heat exchanger 70 for the condensation of the medium C, with: • a bundle of tubes 71 for the coolant medium E to flow therethrough, in which said refrigerant medium, which may also consists of chilled water, arrives thereto via an inlet point 72 and flows out therefrom via an outlet point 73; • a first inlet point 74 for the medium C, which is supplied through a piping 75 connected with the phase separator 29, provided at the outlet 28 of the first heat exchanger 20; • a second inlet point 76 for the medium C, which is supplied through a piping 77 connected with the outlet 68 provided on the top portion 69 of the second evaporation vessel 60; • an outlet point 78 which conveys the same medium C, obviously in its condensed state, outside the apparatus, via a final piping 79 and a first drain pump 80; - the afore mentioned fourth heat exchanger 90, in which the medium A that flows in from the bottom of the second evaporation vessel 60 via the piping 92 connected to the pump 86, is cooled down to the alcoholic fermentation temperature by the action of the coolant medium E (which may also consist of chilled water) and is introduced via a first piping 88 and let out via a second piping 89). Downstream of the heat exchanger 90, and before reaching the fermentation equipment (not shown) there are provided appropriate devices (not shown, either) for the separation, by pressing, of all residual solid contents in the medium A as the latter flows out of the heat exchanger 90 through the piping 93. The apparatus further includes: - a second drain pump 91, which through a piping 95 conveys outside of the apparatus the liquid phase of the medium C flowing in from the phase separator 29 which is located at the outlet 28 of the first heat exchanger 20. In an advantageous manner, such a liquid phase can be mixed up with the medium C, subsequent to condensation in the third heat exchanger 70, and discharged by the pump 80 through the piping 94; - a vacuum pump 81 which, via a conduit 82 connected to that portion of the third heat exchanger 70 (outside the tube bundle 71) through which the medium C flows, sucks and removes the medium F (air) from the apparatus, so as to keep the heat exchangers 20, 30, as well as the evaporation vessels 40, 60 and the tanks 10, 50, in a state of negative pressure, i. e, at a pressure below the atmospheric one. To the purpose of making it much easier to understand the explanation that is given below of the process according to the following invention, a table is attached hereto, in which lists, for a number of significant points of the apparatus: in the first column, the numerical reference of said points as used in the preceding description, the appended claims and the accompanying drawing; in the second column, the designation of the medium that is present in each such point; in the third column, the indication, albeit just in some cases a quantitative one, of .the temperature values reached when the apparatus is working under steady-state conditions; in the fourth column, some notes aimed at making it easier to compare the indicated temperature values with each other. It should right away be noticed that the apparatus is a continuous-duty one, i. e. of the type operating in a continuous manner, so that the described phases follow each other indefinitely without any solution of continuity. The medium A (pressed grapes) is brought from its initial temperature t A o in the inlet conduit 11 into the first tank 10 (acting as a buffer storage) up to the temperature t AM (typically approx. 70° C) at which the heat-assisted maceration phase takes place in the second tank 50, by: - having the medium A pre-heated in the first heat exchanger 20 from t A o to t i by the action of the medium C, generated in the first evaporation vessel 40, i. e. in the stage in which water is caused to evaporate from the medium B and which takes place at the higher temperature tco since it is equal to the heat-assisted maceration temperature t AM - As a result, the temperature of the medium C decreases from tco a the inlet 27 down to tci at the outlet 28; - having finally the same medium heated from tAi up to t A 2, which is equal to the heat-assisted maceration temperature tAM, by the action of the medium D (live steam, i. e. steam produced by a steam generator, the temperature of which decreases in fact from toi at the inlet 37 down to t >2 at the outlet 38) between the inlet 35 and the outlet 36 of the coil 34 of the second heat exchanger 30. During the heat-assisted maceration phase inside the second tank 50, the stirrer 58 ensures a uniform mixing of the liquid part with the solid parts of the pressed grapes (medium A) so as to extract from these parts as much as possible of colour and other substances, e. g. tannin, as needed in view of appropriately enhancing the quality of the wine to be produced, while obviously taking into due account the specificity of the latter. Owing to a pressure which is maintained below the atmospheric one by the vacuum pump 81 inside the first evaporation vessel 40 (which is arranged directly above the second tank 50 and connected therewith via the mouth 42) a significant amount of the water contained in the medium B does actually evaporate. This actually enables that vapour to be obtained, which has been denoted as medium C in the preceding description. According to a basic feature of the present invention, this vapour, i. e. the medium C, which most clearly is at a temperature tco that is equal to the temperature t of the medium A during heat- assisted maceration (i. e. approx. 70° C), is not wasted but delivered to the first heat- exchanger 20 via the piping 44. It ensues that, according to another main feature of the present invention, inside the second tank 50 there takes actually place also the self- enrichment phase. In fact, the medium B, i. e. the must obtained from the filtration of the pressed grapes by means of the filter 52, owing to its loss of water contents caused by the evaporation process that has generated the medium C, has a higher concentration of sugar as compared with the pressed grapes (medium A). The medium B itself is conveyed to the inlet manifold 42 of the second heat-exchanger 30 along the piping 50 in order to be kept at a temperature tβ 2 which is equal to the heat-assisted maceration temperature t AM by the live steam (medium D). Subsequently, the medium B is brought back to the first evaporation vessel 40, and therefore also to the same second tank 50, along the piping 41 coming from the outlet manifold 33 of the second heat exchanger 30. The pressed grapes (medium A), which are still at the heat-assisted maceration temperature t AM and are coming from the second tank 50 along the piping 57, flow through the mouth 62 into the second evaporation vessel 60, as already set forth above. Owing to the combined action of the temperature tA M and the negative pressure conditions brought about by the vacuum pump 81, in said second evaporation vessel 60 there takes place a further evaporation process, i. e. production of medium C by the medium B, of course at a temperature tc2 that is lower than the evaporation temperature tco in the first evaporation vessel 40, i. e. practically at a temperature of approx. 35° C. The temperature tso of the medium B (which derives from the medium A owing to the action of the filter 61) flowing out of the second evaporation vessel 60 through the mouth 63 and the piping 65, is of course equal to the temperature tc 2 of the vapour, i. e. approx. 35° C. The need therefore arises for the medium B to be heated up to a certain extent, i. e. up to a temperature tβi (that is lower than the heat-assisted maceration temperature T AM ), inside the first heat exchanger 20, by the medium C coming from the first evaporation vessel 40 and flowing from the inlet 27 to the outlet 28, before the same medium B flows eventually back to the same second evaporation vessel 60 along the piping 67. The medium C generated inside the second evaporation vessel 60 is in turn transferred to the third heat exchanger 70 through the piping 77, which starts off the top portion 69 of the said vessel 60, in view of being condensed by the coolant flowing through the tubes 71, as this has already been explained earlier in this description. Since a calculation of the heat balance of an apparatus according to the present invention leads to following final equation in which following symbols are used, further to the ones used in the herewith attached table, G A = mass flow of the medium A at the inlet 11 of the first tank 10 Gci = mass flow of the water evaporated in the first evaporation vessel 40 Gc 2 = mass flow of the water evaporated in the second evaporation vessel 60 Gc = Gd + Gc2 rci = latent heat of the vapour coming from the first evaporation vessel 40 rc 2 = latent heat of the vapour coming from the second evaporation vessel 60, with the given temperature values, following final result is obtained Gc = G cl + Gc2 « 0,l * G A which in other words means that the overall amount of vapour (medium C) that is obtained in the apparatus during the two phases of evaporation in the first evaporation vessel 40 and in the second evaporation vessel 60, respectively, amounts to approx. 10%. In practice this translates into an increase by not less than 1 alcoholic degree in the wine being produced. Based on the preceding description, following advantages can be appreciated to derive from the present invention : — the increase in the alcoholic strength of the wine occurs without any need for sugars to be added thereto or grapes with a higher sugar content to be blended therewith; — the usage of heat energy is smaller than in traditional processes, since use is made of not only live steam (medium D), but also vapour (medium C) derived from a partial evaporation of the must (medium B); - the apparatus does not require any particularly complex and/or particularly expensive piece of equipment, whereas it can be appreciated that use can in any case be made of devices differing from the afore cited filters for draining the pressed grapes (medium A). It shall in any case be appreciated that, within the scope of the present invention as recited in the appended claims, the afore described process and/or apparatus may be implemented according to other embodiments. In particular, the addition of a thermal compressor may be provided downstream of the upper mouth 43 of the first evaporation vessel 40 in order to mix part of the mass flow of the medium C with the medium D before the latter is fed into the second heat exchanger 30 through the upper inlet 37. A variant of this kind is certainly more expensive, but is effective in increasing the efficiency of the apparatus. Appendix - Table Designation of the media : A = pressed grapes B = must C = water vapour extracted from the medium B D = live steam E = coolant

Claims: CLAIMS 1. Process for the treatment of pressed grapes in view of producing red and rose wines, comprising in a sequence a phase of heat-assisted maceration of the pressed grapes (A) to extract the desired substances from the solid parts of the grapes, a phase of draining to remove the solid parts from the pressed grapes (A) so as to thereby obtain the must (B), and a phase of self-enrichment consisting in allowing the water contained in the must to partially evaporate so as to increase the concentration of sugars therein, characterized in that said evaporation phase takes place in two stages at two different temperatures (tco, tc 2 ), and that the latent heat of the vapour (C) obtained from the must (B) in the stage at a higher temperature (tco) is used to bring the pressed grapes (A) up to a temperature (t A i) which is above the inlet temperature (t A o) and below the temperature ^ AM ) required by the maceration phase. 2. Process according to claim 1, characterized in that the further increase in the temperature of the pressed grape (A) up to the temperature ^A M ) required by the maceration phase is obtained through the use of heat supplied by an external source (D). 3. Process according to claim 1 or 2, characterized in that at least some of the said phases, in particular the two-stage evaporation phase, take place at a pressure which is below the atmospheric pressure. 4. Process according to any of the preceding claims, characterized in that said phase of maceration of the pressed grapes (A) and one of said two stages of the evaporation phase take place at the same time and in the same position. 5. Process according to claim 4, characterized in that said phase of maceration of the pressed grapes (A) takes place at the same time and in the same position as the evaporation stage performed at the higher temperature (tco). 6. Process according to any of the claims 2 to 5, characterized in that the heat supplied by an external source is in form of superheated water or steam (D). 7. Apparatus for the treatment of pressed grapes in view of producing red and rose wines, comprising: - a first tank (10) acting as a buffer storage adapted to be filled with pressed grapes (A), - first and second draining means (52, 61) for chaining the pressed grapes (A), and thereby obtaining the must (B), associated to two separate vessels (40, 60) which are heated up to a different temperature in order to extract, in the form of vapour (C), part of the water contained in said must (B), - a first and a second heat exchanger (20, 30), in which the pressed grapes (A) are heated up, characterized in that it comprises means (44) to transfer the vapour (C) produced in one (40) of said heated vessels to the first one (20) of said heat exchangers as the medium utilised to heat up the pressed grapes (A). 8. Apparatus according to claim 7, characterized in that also the must (B) is heated in said first and said second heat exchanger (20, 30) using a flow separate from the pressed grapes (A). 9. Apparatus according to claims 7 or 8, characterized in that it also comprises an external heat source for the second one (30) of said heat exchangers. 10. Apparatus according to any of the claims 7 to 9, characterized in that it comprises means (81) adapted to bring about and keep a lower pressure than the atmospheric pressure in at least a part of said heated chambers (40, 60) and heat exchangers. 11. Apparatus according to claim 9, characterized in that it comprises a thermal compressor adapted to transfer part of the flow of vapour (C) produced in one (40) of said chambers heated by the live steam (D) used as an external heat source for the second one (30) of said heat exchangers.

Inventors: NIERO MARIO, NIERO, MARIO
Applicants: NIERO MARIO, VELO SPA, NIERO, MARIO
Application year: 2001
Main classification: C12G1
IPC codes: B01D1, B01D5, C12G1