Free-run juice

Added to the mash, these enzyme activities decrease its viscosity and improve its pressability. The free run juice volume is larger. The yield and then the capacity of the press are increased. 

Betes-Saura C, Andres-Lacueva C and Lamuela-Raventos RM. 1996. Phenolics in white free-run juice and wines from Penedes by high-performance liquid chromatography changes during vinification. J Agric Food Chem 44(10) 3040-3046. 

Somers, T.C. and Pocock, K.F., Phenolic assessment of white musts varietal differences in free-run juices and pressings. Vitis 30, 189, 1991. 

Treatment of pulp with pectolytic enzymes has two additional benefits. Free-run juice is released more readily from the pulp and overall juice yield is increased. Studies with heated Concord pulp containing cellulose fibers have shown that from 1000-gram portions of pulp, free-run juice obtained 5 min after placing the pulp on an 8-mesh screen was increased from 337 ml for controls with no enzyme to an average of 387 ml for lots containing pectolytic enzymes (at a concentration equivalent to that used in commercial operations). This represented an increase of 15% in free-run juice. Total yield, combining both free-run and hand-pressed juice, increased by 3%. (Equivalent yield on a commercial basis would have been 193.6 gal/ton.)... 

Separate fermentations or after assembly of the free-run juice and the pressing juice... 

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). 

Numerous refinements to the initial technique (Flanzy, 1935) have been proposed extended maceration after fermentation has ended at the bottom of the tank racking off the fermented free-run juice and replacing it with fresh must delestage (a mild pumping over) after the initial CM phase, followed by additional maceration and the use of rotary fermentation tanks (at low speeds) at the end of the second phase. 

Trials performed on Shiraz for several years have allowed the comparison of wines produced under three winemaking protocols CM for 8 days (C) CM for 8 days, followed by a 10-day period with a daily pumping over—to maintain contact between harvest and free-run juice (P) same protocol as in P, but with the addition of pectolytic enzymes, before the first pumping over (P) (Flanzy et al., 2001). 

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. 

Quercetin 3-glucuronide was the only flavonol detected in free run juices and wines (Alonso et al. 1986 Betes-Saura et al. 1996), along with trace amounts of kampferol... 

Betes-Saura, C., Andres-Lacueva, C., Lamuela-Raventos, R. M. (1996). Phenolics in white free run juices and wines from Penedes by High-performance liquid chromatography Changes during vinification. J. Agric. Food Chem., 44, 3040-3046. 

The method of sample preparation for grape proteins analysis should be chosen according to the aim of the study. If grape proteins have to be studied in relation to wine characteristics and technology, it is convenient to start from the so-called free run juice , a material representative of the must, in which the proteins are supposed to be involved in the winemaking process and wine quality. The free run juice is obtained by... 

When only proteins remaining soluble after crushing the berries have to be studied, the so-called free-run juice can be prepared. To prepare the free run juice, the suspension obtained from squeezing the berries is filtered through cloth and the suspended particles are separated by centrifugation. The soluble proteins can be concentrated by ultrafiltration on membranes with a cut-off lower than 10 kDa (Waters et al., 1998). Proteins can be collected from the (concentrated) solution by the classical methods for protein precipitation, such as ammonium sulphate at 80% saturation, or organic solvents added to a final concentration... 

An example of a chromatogram relative to the protein analysis of a free run juice by Anion Exchange Chromatography is shown in Figure 7.7 (Vincenzi et al., 2005). Contrary to proteins, grape and wine peptides have not been studied by IEC. 

Figure 7.7 Anion Exchange Chromatography of the proteins from the free run juice of grape of cv. Incrocio Manzoni 6.0.13. Column Tricorn Mono Q 5/50 GLM detection at wavelength 280 nm buffer A Tris-HCl 20 mM pH 8.5 buffer B buffer A containing NaCl 1 M gradient program from 0 to 14% of B in 70 min, from 14 to 100% B in 20min and from 100 to 0% B in 5min flow rate 0.6mL/min (Vincenzi et al., 2005)...

Kinzer and Schreier (77) found that, compared with free run juice, pressings contained higher concentrations of monoterpene alcohols. When a pressing aid was used, wines made from the juice contained 34-38% less monoterpenes than wines produced from the same system without pressing aid. Bayonove et al. (78,79) also studied effects of pressing and of skin contact in muscat musts. 

The natural strawberry material was prepared from a good commercial grade of frozen Blakemore strawberry juice. Its history showed that it had never been pasteurized, was pressed on stainless steel equipment, and had not been otherwise abused. The frozen juice was slowly thawed and the early free-run juice was collected at a soluble solids content of 22% (St J). 

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. 

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