Pre-Fermentation Treatments
Enzyme Addition
Enzymes are natural protein catalysts that facilitate and increase the rate of chemical reactions during winemaking (Chapter 20). The beneficial action of natural enzymes from grapes is often limited by must pH or an insufficient activity due to the limited duration of pre-fermentation treatments. Although they occur naturally in wine grapes and yeast, commercial enzymes are commonly used by many wineries. Commercial enzymes are not usually the simple product of just one activity. For example, the product in question may have a main pectinase activity but a secondary glucosidase, or glucanase activity.
Pectic Enzymes
Pectic enzymes are also known as pectinases or pectinolytic enzymes provide a number of other technical advantages including an increase in free-run yield in draining and pressing operations and improved clarification by natural settling. This all leads to an overall improvement in the grape must quality, with increased aroma, and polyphenol concentrations. The pulp of the grape varieties is rich in pectin compounds, also known as pectic polysaccharides.
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