TY - JOUR T1 - The Effect of Pectic Enzymes in Wine Making JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 59 LP - 75 DO - 10.5344/ajev.1951.2.1.59 VL - 2 IS - 1 AU - W. V. Cruess AU - R. O'Neal AU - George Chong AU - Dan Uchimoto Y1 - 1951/01/01 UR - http://www.ajevonline.org/content/2/1/59.abstract N2 - 1. Yields of free run and total yields of wine per ton of grapes have on the average been greater from enzyme treated than from untreated crushed grapes.2. Use of pectic enzymes in crushed white grapes almost invariably deepened the color of the wine in comparison with that of wine made from grapes to which no enzyme was added--probably owing to greater extraction of color from the skins.3. Color of wines made from free run juice to which was added a pectic enzyme was in mamy cases about like that of the untreated wine, but also in about an equal number of cases the color of the treated wines on aging became slightly deeper (yellower) than that of the untreated wines.4. Therefore, if light color is the primary objective, the enzyme should be added to the white juice rather than to the crushed grapes.5. Enzyme-treated wines have invariably matured more rapidly than the untreated. The wine maker must be careful not to let the treated wines overmature before bottling. In one winery experiment of the 1950 season the enzyme-treated wine is now inferior to the untreated in flavor and bouquet. In other cases there is little dlfference, or the enzyme treated is superior.6. Enzyme-treated wines developed much more compact lees than the treated and were racked with less danger of carrying lees over into the wine.7. As in previous seasons (1936-1949), we found that the enzyme-treated wines cleared much more rapidly than the untreated.8. Also, they filtered much more rapidly and much more wine could be filtered with each setting of the filter.9. Much less bentonite was needed for clarification of the enzyme-treated wines--usually 1½ - 2 pounds per 1000 gallons as against 4 - l0 pounds for the untreated.10. At two wineries relatively small amouts of Pectinol have been used, ¼ to ½ pound of Pectinol-0 per ton. The wines so treated do not clear as rapidly as with larger additions of enzyme but are found to filter very much more rapidly than the untreated and to require far less bentonite in clarification.11. Enzyme-treated juices were found commercially to filter more readily and to give concentrates of better quality than the untreated.12. As reported by Berg and Marsh, it was observed that Pectinol greatly increased the rate of clearing of heat extracted fermented red musts. Usually the enzyme-treated heat extracted wines in our experiments were of deeper color than the checks, indicating that the enzyme may have stabilized the color.13. On the other hand, where the enzyme was used in the crushed grapes without heat extraction the color of the resulting dry wines were in some cases less intense than in the check lots. In others it was more intense or about equal to the untreated.14. No very clear cut differences were observed in the effect of several different Rohm and Haas enzyme preparations on the color of either red or white wines.15. Enzyme-treated white wines darkened more rapidly than the untreated when incubated at 55° C (131° F), although the difference was usually not very great.16. Preliminary evidence was found to indicate that galacturonic acid formed by hydrolysis of the pectin of the must by the enzyme may be concerned in the darkening of the color of enzyme-treated wines.17. Pectinol solutions of the concentrations applied in wine making did not darken; indicating that where darkening of the treated wine occurs it is some constituent of the wine itself that is concerned.18. Ports made with Pectinol were in most cases deeper in color than the untreated.19. Enzyme-treated musts foamed much less than the untreated during fermentationo20. There appeared to be no consistent differences in heat and cold stability of enzyme-treated and untreated wines. Finished enzyme-treated dry white wines were stable at 131° F and at 0° F.21. Maintenance of a reasonable level of SO2 in enzyme-treated white wines held the color. ER -