The Cellar Dweller


Where did all the colour go?


Blending wine varieties isn’t the only way to develop and stabilize it.


By Gary Strachan


hate it when I think I have the perfect colour for a red wine and later find that the wine becomes a pale imitation of itself. My perfect colour is now coating the inside of the bottle and clinging to the sediment in the bottom of the bottle. I wrestled with this problem for a long time before I encountered an explanation that made sense to me.


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I’ve written a previous column about the phenomenon of copigmentation in red wines. Colour development can often be enhanced by blending wines of different grape varieties. The best known of these is the stabilization of colour in Syrah by blending Viognier with it. It need not be a blend of wines. Extraction of phenolics from spent Viognier skins will also enhance and stabilize the colour of Syrah. The important point is to provide the building blocks for the polymerization of anthocyanins and phenolic compounds that contribute to stable, appropriate colour.


I won’t go into the details of biochemistry that contribute to copigmentation. The bottom line is that each grape variety has a unique phenolic profile. By combining the phenolics of two or more varieties, the anthocyanin pigments can usually develop a more stable structure with more intense and persistent colour.


Oxidation also plays a role because acetaldehyde forms a bridge to stabilize the polyphenolics into a three


30 British Columbia FRUIT GROWER • Summer 2014 Oxidized tannin precipitate in the bottom of a wine glass.


dimensional configuration, sort of like holding two pieces of bread together with jam and peanut butter. Polyphenolics are also often called tannins, because the polyphenolics from plants have been used for centuries to stabilize the protein (tanning) of animal hides. Although I prefer to control the extraction by adding spent skins of a complementary variety to a fermentation, fermentation tannins from many sources are commercially available.


The advantage of purchased tannin is that it comes with directions and has a reasonably predictable outcome. Added tannins can be administered at any


point during extraction, fermentation, or pre bottling, and for different reasons. In addition to colour stabilization, tannins can affect mouth feel, nose, and astringency and contribute to protein stability in white wines and rosés. Achieving appropriate astringency and colour stability with vinifera varieties is reasonably straightforward by comparison with typical hybrids. Many hybrids such as Maréchal Foch, Marquette, and Baco noir are notorious for their initial dark pigmentation which later precipitates in the bottle. All of the factors which affect colour content and stability in vinifera wines also affect wines from hybrid grapes: grape


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