Is it okay to use my normal settling enzyme for red wine maceration?

February 3, 2010 posted by Karien O'Kennedy

This is a question I got from a winemaker a few days ago. Some people selling enzymes will say yes, that any pectinase preparation you use will be better than using nothing at all. I suppose that can be the case. However, here are a few facts to consider when choosing an enzyme for red colour/tannin extraction.

Colour and tannin are mostly situated in red grape skins. The pectin structure of grape skins is much more complicated than the simple structure of the pulp. When your aim is settling only, you work with the pulp of the grape. A simple pectin structure only requires the basic pectinase activities of pectin lyase, pectin methyl esterase and polygalacturonase. That is why settling enzymes are the most cost effective to produce and usually the cheapest of an enzyme supplier’s range of enzymes.

If skin contact is your aim, you need additional enzymatic activities to break down the highly branched, complex pectin structure of skins. So in addition to the basic pectinases, skin contact enzymes contain various “side” activities. The production organism – Aspergillus niger – produces much less of these side activities than the basic pectinases. That is why production of skin contact enzymes is more expensive and you, the end user, has to fork out more. It is a specialised enzyme for a specialised application. So basically skin contact enzymes contain all the components of a settling enzyme, usually in higher concentrations, as well as specific side activities that will work on the more complex pectin structure of skins.

So, common sense will tell you that an enzyme specifically recommended for skin contact will therefore be way more efficient in extracting colour and tannin than a normal settling enzyme. But wait…there is more….if you order now, you get this beautiful set of steak knives absolutely free!!! OK I digress; seriously there is one more factor to keep in mind.

Aspergillus niger also produces a group of enzymes called glycosidases during the commercial production of pectinases. It actually falls under the group of side activities formed. It does it automatically, with some strains producing more than other. Glycosidases remove sugar molecules from more complex structures. In grapes, certain potentially flavour active compounds are bound to sugar molecules. In this bound form they are not flavour active. When the sugars are removed, you can smell and taste these compounds. An example is monoterpenes found in most white grape varieties, especially Riesling and Muscats. They are also found in red grapes. However, red wine colour, anthocyanin, is stabilised by sugar molecules. So by removing the sugars from anthocyanins, glycosidases can destabilise them, making your red wine colour, unstable. So what is a positive in white is a negative in red. Red wine enzymes should preferably not contain any glycosidases, or, as they are more commonly known in this case – anthocyanases.

My advice to you would thus be: make sure that the enzyme preparation you plan to use for red must maceration contain negligible levels of anthocyanase. If your supplier cannot give you that assurance, then switch to a supplier that can give you that assurance. No point in being penny wise and pound foolish. There are ways enzyme companies can manipulate production of red skin contact enzymes to minimise this activity. They generally, however, do not try to limit this activity in white enzymes, such as settling enzymes, since it is a positive for white wine aroma.

Having given you the scientific facts, my personal answer to the above question would be: no, it is not OK to use your settling enzyme for red skin contact. However, if your supplier can guarantee you that the anthocyanase activity in their settling enzyme is negligible, then I suppose some pectinase activity is better than none.

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Tags: anthocyanase, colour extraction, glycosidase, red wine maceration, wine enzymes

2 Responses to “Is it okay to use my normal settling enzyme for red wine maceration?”

John Kelly Says:
March 4th, 2010 at 7:48 am
Hi Karien: The requirement that enological enzyme preps be free of glycosidic side activities is absolute, and not just for red wines. Novo and others have developed products where the selling point is the glycosidase activity itself. These preps do a wonderful job of liberating aromatic compounds from glycosidic precursors – wines so treated have a significant increase in perceptible aroma relative to untreated wines. They also age extremely poorly in bottle. These enzymes are suitable to make very fruit-forward wine styles that can be bottled with synthetic stoppers – the understanding being that they should be consumed within a year of bottling.

The evolution of aromas in vins de garde bottled with cork or screw cap also involves the slow breakdown of glycosidic precursors. The difference in this kind of aging is that alcoholysis can occur in addition to hydrolysis – the small fraction of ethers hypothetically produced may account for the increased complexity of aroma in normally aged wines compared to those where the aromas have been liberated by glycosidase. (I say hypothetical as this is a gedanken experiment – I don’t know of anyone who has actually published a study showing this – would be interesting to propose).

These glycosidic enzymes are typically added pre-bottling. This points out another reason we don’t want glycosidase side-activity in our other enzyme preps: typically we add these enzymes before fermentation. Fermentation will carry off a much higher fraction of aromatics. Glycosidase activity does not just destabilize color, it will result in an aroma-deficient wine.

- John
Karien O'Kennedy Says:
March 4th, 2010 at 11:55 am
Hi John,

Yes there are commercial pectinase preparations containing high concentrations of glycosidases, specifically aimed at liberating glycosidated flavour active compounds such as monoterpenes and C13-norisoprenoid derivatives. An example of such an enzyme is the DSM Rapidase AR 2000. It is very powerful indeed. The way you use it is to treat only part of a blend and not the whole blend that is going to go into the bottle. You also remove the enzyme with bentonite to stop its activity from continuing in the bottle. That way you achieve immediate upfront fruityness as well as longevity. If you treat your whole blend and not remove the enzyme before bottling, it is then that you lose longevity. Another important thing to keep in mind is do you want to over express a monoterpene flavour profile in certain wine styles? In whites it is usually tropical, floral and muscat like. It fits certain wine styles and not others.

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