There are many enzyme-catalysed reactions which occur naturally during winemaking. These can influence juice extraction, settling, colour or tannin extraction, turbidity and filterability. The addition of enzymes to juice is commonly used to break down pectin and improve settling and filterability. Enzymes can be also used to improve extraction of colour and tannin from red grapes.
Background and application
Commercially prepared pectolytic enzymes can be added to help extract more juice from grapes than otherwise would naturally occur within a limited timeframe. There are many commercially available pectolytic enzymes preparations available and most of these consist mainly of two particular enzymes, pectin methyl esterase and polygalacturonase (Boulton et al. 1996).
Commercially available macerating enzymes can be added to improve the extraction of colour and tannin from red grapes during fermentation. This extraction occurs naturally as the grapes are crushed; however, the addition of enzymes can increase the cell wall breakdown of the grape skin, increasing colour and total phenolic content and potentially resulting in a fuller bodied red wines (Sacchi et al. 2005).
Practical and logistical considerations
The amount of enzyme added should be in accordance with the manufacturer’s instructions. Additions to red must should be made post-crushing (no stalks). Mixing after the addition is recommended to ensure even distribution of the enzyme. Additions are typically very small, so diluting in a little water and adding slowly can help achieve even distribution.
Boulton, R.B.; Singleton, V.L.; Bisson, L.F.; Kunkee, R.E. 1996. Principles and practices of winemaking. New York: Chapman & Hall.
Sacchi, K.L., Bisson, L.F., Adams, D.O. 2005. A review of the effect of winemaking techniques on phenolic extraction in red wines. Am. J. Enol. Vitic. 56: 197-206.