The Heat Is On

Temperatures are approaching freezing in Santa Barbara County, so the heaters are on as malolactic fermentations proceed
Dec 1, 2009

With nighttime temperatures dipping into the lower 30s Fahrenheit here in Santa Barbara County, it is cold enough now that we have turned the heaters on in the winery to keep the temperature at 58° F. With fans to circulate the air and temperature monitors to verify, the temperature in our north-facing, insulated winery varies about a degree either way.

58° F is a good temperature for the occurrence of the malolactic fermentation (aka secondary fermentation, or ML), in which malolactic bacteria convert malic acid into lactic acid. If it were colder, the ML fermentation would slow, and if warmer it could encourage the growth of unwanted bacteria and yeast. I've been listening to the barrels crackle and tasting some of the wines, and the ML is visibly and audibly in full swing. The perception of acidity is already decreasing and the wines are softening.

Unbeknownst to many people who believe they are allergic to sulfites in wine, many of them are actually allergic to histamines produced by some strains (especially wild strains) of the ML bacteria. Allergies are a serious problem for many. To avoid problems, we and many other winemakers use strains of bacteria that have been selected because they perform the secondary fermentation without producing histamines.

Occasionally it is true for some people that they cannot drink wine because they are allergic to sulfites. But in many cases these people are able to eat dried fruit without suffering an allergic reaction. In reality, dried fruit contains much higher levels of sulfites than wine. This suggests that frequently the allergy is more likely caused by histamines that are found in some wines. This is something that more and more winemakers have been taking note of during the ML, to produce wines that these allergy sufferers can drink without an allergic reaction.

After the malolactic fermentation is complete, the wine will move from the reductive state it is in during both the primary (sugar) fermentation and the secondary (malolactic) fermentation, to one where it can absorb small amounts of oxygen and begin to age. That is the point where the wine begins to dance on the line between reductive and oxidative. This ballet begins after the conclusion of malolactic in February, when the wine is removed from the lees (sediment of yeast bodies) that tend to absorb oxygen and the wine is racked to clean barrels.

We winemakers are proud of the wines that we make and always ready to extol the virtues of our craft. With all optimism appearing deserved, at this point the dissolved CO2 from primary fermentation and the ML fermentation hides the wine to some extent, making the perception of tannins sharper and more aggressive. By January and the completion of ML, we will get a much better glimpse of what we have in barrel.

But that won't stop us from pouring barrel samples this coming weekend for the Santa Barbara County "Holiday Weekend in Wine Country" open house. If you read this blog and happen to stroll through our winery doors, please introduce yourself!

Harvest United States California Santa Barbara County 2009

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