Thank you Darla Hoffmann, Dustin Chabert, and Jeremy Eubanks for your input last week on Sustainable Viticulture. Take a look if you missed it!
This week: Co-fermentation
What is co-fermentation and what effect(s) does it have on the fermentation process and final wine?
To add to Dustin's response, the method of fermenting 2 or more grapes in one vessel started in the old world but made it's way to the new world as well, because of the notable, interesting and complex results. It is most common in field blends where different wine grapes all from the same vineyard are harvested at the same time. The grapes are easier to harvest together than to sort out individually, however they would seemingly display more characteristics of terroir being that the grapes grew side by side in the same vineyard. Introducing these grapes before fermentation provides different characteristics due in large part to the raw materials being combined. Blending already fermented wines will not be exposed to those same materials because the composition has already been altered. Co-fermentation promotes inter-mingling of these grapes early so the texture is much more harmonious. (maybe somewhat like 2 people meeting and forming their own opinion about each other, without the manipulation of others??) In other words, the grapes have a chance to co-exist and see how things turn out. After the initial meeting, it is much harder to make changes. There is no real way of knowing if a wine is co-fermented as there is no law requiring this to be listed on the bottle. However, some winemakers may choose to mention it on the label.