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THE ROLE OF COOLING AND HEATINGIN MODERN WINERIES1.ABSTRACTThroughout the world wine production is growing, and continuous research into new technologiesis being pursued to obtain better quality. The most advanced technologies are cooling and heatingsystems that produce wines of higher quality to satisfy the large market demand.After an in-depth examination of the vast influence of temperature in different wine productionprocesses, this paper shows the various techniques for obtaining high quality wines by the skillfulapplication of cooling and heating. Recommendations for typical cooling and heating plants aregiven to complete the picture.Triacca, Bianzone – Italy: 14th CENTURY MONASTERY, NOW WINE ESTATE AND AGEING CELLAR2.INTRODUCTIONWine has been produced for thousands of years throughout the entire Mediterranean basin and“Bacchanalia”, the big wine festivals, have been described by ancient writers.In addition, wine has always been the subject of trade among many nations, as proven byarchaeological findings from Greek and Roman vessels, carrying amphorae of wine, oil and grain,which sank in the Mediterranean Sea,.The wine trade is respected for its high quality wines, and this paper will show the strong role thatthe application of the most advanced technologies of cooling and heating now plays in achievingthis result.THE ROLE OF COOLING AND HEATING IN MODERN WINERIES1/10

3.WINE PRODUCTION BY COOLING AND HEATING3.1.White winesMechanized cooling systems have already been used for making white wines for many years.Previously, vines producing prestigious grapes for white wines were cultivated almostexclusively in areas with moderate temperatures to avoid sudden temperature changes. Whitewine consumers are also moving towards full-bodied wines and, for this reason, vine growingfor white wine, has also moved further south.In these areas, however, temperatures at harvesting time are too high which prevents thewines from having an intense and persistent aroma.The harvested white grapes are delivered to the wineries wher e they are deposited in bigcollecting augers where they are pressed and stripped of the stalks and sent to the pressingmachine.During this phase, there is normally a considerable temperature drop so before arriving at theaugers the grapes go through headers to lower the temperature.Dry ice should be added to the grapes during transportation or failing that, in the augers onarrival at the winery. It’s evident that reducing the temperature immediately after picking isextremely important to safeguard the wine’s aroma.In prestige areas the grapes are collected in crates and then stored for a period of 3 -4 days,before pressing, in special warehouses with temperatures controlled between 6-9 C.A new technology using CO 2 has recently been introduced. This consists of freezing the grapesurface to preserve its physical and chemical characteristics.In white wine production, another widespread technique, hyperoxidation, has been recentlyintroduced. An extensive use of cooling is necessary for this process.The grapes are pressed immediately and the must is quickly cooled, and preserved at 3 -5 Cfor 6-10 days. After this period, the must is heated to 15-18 C and fermentation starts.A controlled temperature of 16-18 C for white wine making is essential.The production of sparkling wines, the Charmat method, with fermentation in an autoclave,must be controlled at a low temperature to obtain fresh wines rich in primary and secondaryaromas.The temperature control is also fundamental in the production of classic sparkling wines andChampagnes. Not all areas are like those in the Champagne region, where the most winerieshave caves or undergrounds tunnels where the natural internal temperature coincides with theoptimal temperature for wine preservation, both during fermentation and the long storage ofbottles waiting for the “disgorgement” and refilling before selling.3.2Rosé winesThe rosé wine making process is similar to that of white wine, as aroma and freshness are theirspecific characteristics. Red grapes are picked, stripped, pressed and stored in tanks, the mustremains in contact with the grape skins for only for few hours. It is immediately tapped to avoid theextraction of excessive tannin and color from the grapes. Controlled fermentation at 14-18 Cfollows until the end of alcoholic fermentation.THE ROLE OF COOLING AND HEATING IN MODERN WINERIES2/10

3.3Red winesThe cooling system in red wines production has not been used much up to now. Mainly in hotclimate areas such as the south of Italy and other similar places throughout the world, strong redwines were mainly produced for blending rather than quality. Recently there has been an importanttrend change, and southern Italy is now oriented to producing high quality wines, and for thisreason, a rational and dedicated technique, where the temperature plays an important role, isnecessary for the production process.Recently, in Milan, a biennial show exhibiting tools and equipment for wine production has clearlyconfirmed that the most wine producers are equipped with a temperature control system.3.3.1 CryoextractionThis consists of the extraction of the varietal aromas from the pressed grapes before fermentation.The grapes are pressed, stripped, destalked and stored in the fermentation tank. The temperature ofthe grapes is lowered to 4-5 C for a period of 4-6 days and as a result the autochthon yeasts of thegrapes are quiescent due to the low temperature, while the aroma from the skin of pressed grapes istransferred to the must. After several days the fermentation starts raising the temperature and theselected yeasts are introduced.3.3.2 Controlled temperature in wine makingMuch heat is generated by the alcoholic fermentation and the yeast survives and works intemperatures not exceeding 31-33 C. At higher temperatures, there is the risk of fermentationstopping, which is the big problem for the winery technicians. It is quite difficult to restart analcoholic fermentation which has been stopped by too high a temperature, hence the importance ofcooling the fermentative mass. During the first few days this can be done by heat exchangers insidethe tanks, or even better by using double-wall tanks. In winery designing it is important to realizethat the bigger the capacity of the tank, the greater the cooling demand to maintain the temperature,as the heat produced by the fermentation is directly related to the quantity of the must.Triacca, Bianzone – Italy:“BARRIQUE” CELLAR FOR AGEING RED WINESTHE ROLE OF COOLING AND HEATING IN MODERN WINERIES3/10

4.TEMPERATURE ROLES IN WINE MAKINGRecently it has been noticed that winery technicians exploit the various alcoholic fermentationphases to extract aromas, anthocyanins, polyphenols, colors etc. at the best moment and mostconvenient temperature for each component to enhance the final product. In this way aromas areextracted when the must is cold before start of alcoholic fermentation. Removing the large quantityof grape seeds deposited in the bottom avoids the massive extraction of crude and unnecessarytannins after that the temperature is raised up to 42-44 C for a period of 8-12 hours to extract theanthocyanins. Then the temperature is reduced at 25-26 C, thus starting the regular alcoholicfermentation.Before the grape pressing the temperature is raised again to 34-36 C to extract, if required, anadditional quantity of polyphenols if the characteristic of wine requires it.Typical grapes must temperatures in wine productionRED WINECryoextractionColor extractionAlcoholic fermentationAdd. col. ExtractionMalolactic fermentationWine conservation 4/ 5 C 37/ 38 C 25/ 27 C 38/ 40 C 18/ 19 C 14/ 16 CROSE’ WINECryoextractionAlcoholic fermentationMalolactic fermentationWine conservation 4/ 5 C 14/ 16 C 17/ 18 C 12/ 14 CWHITE WINEHyperoxidationAlcoholic fermentationMalolactic fermentationWine conservation 4/ 5 C 14/ 16 C 17/ 18 C 12/ 14 CTriacca, Villa Di Tirano – Italy: FERMENTATION PLANTTHE ROLE OF COOLING AND HEATING IN MODERN WINERIES4/10

5.WINE MAKING PROCESS5.1Malolactic fermentationThe malolactic fermentation is the biodegradation of malic acid into lactic acid which frombiological point of view produces more stable wines (mainly red wines) with the correct acidity forthe taste. Bacteria that attack the malic acid increase and are active when the wine temperature is atleast 18 C. In double-wall tanks, a water-glycol solution at 20-22 C is circulating to maintain atemperature of 18-20 C inside the tank. As the chemical reaction is endothermic, a small amount ofheat is required.5.2Malolactic fermentation inhibitionIn the production of white and rosé wines malolactic fermentation is usually inhibited or stopped, asthis fermentation is the biodegradation of the malic acid in lactic acid and carbon dioxide, topreserve the acidity and freshness typical of these wines. Also, this process which in the past wasdone by adding large quantities of sulfur dioxide, is now done by cooling the mass thus avoidingthe a.m. biodegradation.5.3Wine’s tartaric stabilizationGenerally, wines, mainly those that are not aged, contain too much potassium. If bottled withoutremoving it, the excessive tartrates will turn into crystals. To avoid this visual defect, the wine ischilled before bottling. This entails dropping wine temperature to minus 2-3 C for approximately10 days., aiding the crystallization of tartrates by adding other crystals which work as crystallizationcenters.Today, stabilization is achieved by the so-called continuous method that consists of cooling thewine and adding crystals through a shell-and-tube heat exchanger, so that the newly generatedcrystals are immediately separated in a continuous process.In middle sized and small wineries, this process is done intermittently by the contact system,consisting of dropping the wine temperature close to 0 C, introducing the crystallizers and shakingthe wine continuously for about an hour in order to combine the wine with the small crystalsintroduced to generate new crystals: in this way, the potassium excess is stabilized.Red wine alcoholic fermentation:typical cycle13579THE ROLE OF COOLING AND HEATING IN MODERN WINERIES111315Days5/10