Crushing grape

To show correlation between occurrence of malo-lactic fermentation and bacterial inoculation, and to show consistency of results among the control lots and inoculated lots, it is imperative that the division of lots be made before alcoholic fermentation. For red wines, great care must be taken to obtain equitable distribution of the crushed grapes in each of the lots. The inconsistency in the results mentioned above may have been caused by variation in amounts of grape skins during the alcoholic fermentation with the accompanying effect on fermentation temperature, sulfur dioxide concentration,. pH after pressing, and concentration of nutrients (55, 56). 

Caxignan tanks (110 hi) of conventionally produced (CP) wines vinified with crushed grape harvest and carbonic maceration (CM) wines. After pressing F, free-run juice, P, pressing juice FP, assembly of F and P. Total potential alcohol = produced alcohol + alcohol corresponding to the residual sugars (Andre et al, 1967). 

For white wine production, the grapes usually were not stemmed. The crushed grapes were left for six to ten hours before the free-run (separated) juice was drawn off. The pomace was then pressed and the pressed pomace was washed as with red pomace. The fermentation of white musts was done in 2/3-full oak casks. The fermentation was watched daily. The yeast foam was removed. By the sixth day, the fermentation had slowed down sufficiently to then use a fermenting bung. The Italians often use a bag of sand, which they place over the bung-hole. He recommended fermenting room temperatures of 21°-27° C and cellar temperatures of 15.6°-21° C, preferring 15.6° C after the first year. 

One of the main objections to the Garolla-type crusher is that a small amount of the stems passes through the one-inch-diameter cylinder perforations with the crushed grapes. The crushed grape mass is the must. Operation of the shaft with the paddles at a lower speed reduces the stems going in with the must. 

Must and Wine Yield. The wine gallon yield per ton varies with type of grape, whether white or black. Total wine gallon yield is composed of three fractions. The main volume is the free-run juice that flows from the crushed grape second is the drain screen juice that separates from the pomace, which already has had the free-run juice removed and third is the press juice from the tight squeezing of the screen-drained pomace that was conveyed to the grape press. 

The addition of calcium sulfate to the freshly crushed grapes in warm low-acid regions has many advantages. First, of course, it reduces the pH without raising the total acidity, by changing KHTa to H2Ta (where Ta represents the tartrate radical). The reaction is ... 

For the production of white wine, it is almost universally accepted that a relatively clear juice of 0.5-2.0 percent suspended solids is desired for fermentation. This is achieved by separating the juice from the skins, pulp, and seeds. Many of the small wineries use a horizontal basket press to receive their fresh must. These presses utilize either an inflatable bladder or a movable piston to press the crushed grapes. In many cases, the must is pumped directly to these presses from the crusher-stemmer. An exception to this method of operation in small wineries is the case where skin contact is desired. Several wineries will allow maceration for from four hours to twenty-four hours for V. vinifera cultivars Chardonnay and Gewiirztraimer. 

Chemometric techniques have also been used to identify grapevine cultivars and clones based on the H and NMR of polyphenols observed in extracts/ Extractions from crushed grape seeds and vines obtained in France were analyzed using HMBC and HMQC (heteronuclear multiple quantum correlation) 2D NMR... 

Ten small scale fermentations were established with 5 L of crushed grapes from Vitis vinifera L cv. Cabernet Sauvignon. Each must was inoculated wiA a population of 10 cfii/mL of one of the ten yeast strains, all these belonged to Saccharomyces bayanus or cerevisiae. Three yeast strains of each regions were isolated from grapes collected in the Spanish apellation controUe regions of La... 

In a day or two the must is in full fermentation and may be used as a starter. From ten to thirty gallons of starter are used for every thousand gallons of must or crushed grapes. The cooler the grapes the more should be added. Too much added to warm grapes may make the fermentation so rapid that it will be difficult to control the temperature. Moldy or dirty grapes require more than clean, because there are more injurious germs to overcome. 

Fermentation.—The general considerations involved in the fermentation of grapes to produce wine have been discussed in Chapters V and VI. The fermentation of the crushed grapes is started as desired, either naturally or by means of a starter, and means to control the temperature must be available if very large batches are being fermented. These may include water cooling coils or as in parts of California, the construction of... 

Crush grapes in a large fermenter. Pitch yeast starter. When fermentation is completed, strain out the fermented juice. Either discard the wine or bottle it. Add 5 gallons of water and honey to the fermenter containing the grapes (must). Allow to ferment to completion. Press out wine and rack to a 6 gallon secondary. Rack 3 months later. Bottle the following fall. 

Vatting is the period between the time the vat is filled with crushed grapes and the wine is run off. Its duration varies from a few days to three weeks, or even longer, depending on the type of wine. It may be divided into three distinct parts (Figure 6.41) ... 

Removal. Use of pectolytic enzymes as an aid to the clarification of grape juice has been studied by Willaman and Kertesz (1931) and Mehlitz and Scheuer (1934). Hickinbotham and Williams (1940) and Besone and Cruess (1941) used commercial preparations successfully for clarifying the must. The resulting wines also clarify more rapidly. Cruess and Kilbuck (1947) added the enzyme to the crushed grapes to increase the juice yield. They obtained 6.5% more free-run juice when one part of the enzyme was added to 1000 of the crushed grapes, which were then allowed to stand overnight. They claimed the wines cleared more rapidly. 

The objective of heat treatment is to increase color intensity in grape juices and wines. Heat treatment of crushed grapes also increases extraction of other phenols and destroys oxidative enzymes (Garrido et al, 1993). The temperature and time used during the heat extraction will influence the color intensity, acidity, pH, and extraction of phenolics (Wagener, 1981). 

The results of the present studies showed that wines made from immediate press juices of the three varieties had the lowest total phenolics among all the treatments (Table 1). Heat treatment of the crushed grapes extracted phenols from the skins, but to a lesser extent than any of the hull treatments. In all varieties, hot press wines and juices were much higher in flavonoids and total phenolic content than immediate press wines and juices. The total phenolic concentrations of hot press wines and juices from Cabernet Sauvignon and Noble were shown to be lower than all the skin contact wines. However, for Chambourcin, hot press wine had the highest total phenol concentration among all treatments, and hot press juice had a similar phenol concentration to skin contact wines. 

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