This is just a pretty picture of grapes, because pictures of carbonic maceration are hard to find…

Carbonic maceration sounds kinky, but it’s totally G-rated. Except that it yields alcohol. So you can talk to kids about it, but they don’t get samples.

Fermentation is the main way alcohol is created for wine and beer. In that process, yeasts consume sugars and then generate alcohol, heat and carbon dioxide. Fermentation is also responsible for many of the unique flavors in wine, some of which are generated by the fermentation itself and others coming from alcohol-soluble compounds in the grapes.

Carbonic maceration also creates alcohol, but without yeast. It is an intracellular fermentation that takes place in whole (uncrushed) fruit. Some of the sugar and malic acid is converted into a small amount of alcohol.

Carbonic maceration generates different flavors than regular alcoholic fermentation. Notes of bubblegum and banana are typical and the fruity aspects seem brighter. Carbonic maceration extracts less texture and color from the grapes too, because the those compounds require more heat and alcohol to be released by the grape skins.

Even wines well-known for being made with carbonic maceration, such as Beaujolais, also use yeast-based fermentation and are more accurately described as having gone through “partial carbonic maceration.” One reason is that intracellular fermentation alone wouldn’t generate enough alcohol and too much residual sugar would remain. The other reason is that yeast-based fermentation is hard to avoid.

The skin of ripe grapes is easily broken. Even if a winemaker is careful with de-stemming and avoids mechanical crushing, grapes on the bottom of a tank will be pressed by the weight of those above them. Grapes on top may only experience intracellular fermentation, those on the bottom only yeast-based fermentation and those in the middle varying combinations of both. To preserve freshness and encourage carbonic maceration by discouraging the yeast, winemakers may blanket the tanks with carbon dioxide.

Gamay-based wines, such as Beaujolais, aren’t the only ones to utilize partial carbonic maceration. It is common for Carignan and, increasingly, Pinot Noir, Syrah and Grenache. In Pinot Noir and Grenache it mostly adds complexity and friendly, lifted fruit notes. In Syrah and Carignan, both of which can be quite tannic, it makes the wines softer on the palate.

Copyright Fred Swan 2016. All rights reserved.