October 29, 2008

More winemaking at home

Things are continuing well on the home winemaking front. When we last left off, the three bins of pinot noir were still cold soaking in the garage while I had a natural fermentation starter warming up in the house.

I spent a good bit of time warming the garage with a space heater, an aquarium heater in the bins themselves, even my warm car. Anything to get the air temp up and then the must temp to get the conditions right for fermentation.

Once the temperature was in the 60s, I poured part of the starter in the center of each bin and left it to give the natural yeast a boost in reproduction. The next morning there were signs of fermentation but nothing vigorous. There were also some acetone smells, something that drives winemakers crazy, especially those who think natural fermentation is stupid. I smell acetone in varying degrees in lots of ferments, especially at the beginning before any yeast has gotten established, whether you added it or not.

The idea is that once the ferment warms, the acetone producing yeast will die off and the smell itself will either blow off by fermentation action or be metabolized by the yeast. Not sure, honestly, what it is, but sure enough that smell is long gone now.

After another day, the ferments were really going, producing lots of carbon dioxide that pushes a "cap" of grape skins above the surface of the liquid, just as yeast in bread dough cause it to rise. I punch down the cap in the morning and at night to moderate temperature in the bins, and especially to get the skins in contact with the liquid so that the aromas and flavors continue to get into the new wine.

Here's a picture of the bins with high caps. Notice that the grapes are a few inches higher than they were during the cold soaks.

Here's a close up of one bin to get a better look. As the ferment continues, the color of the grapes turn from the dark purple / blue we saw before to something much more ruby like.

Over the last two days, the fermentations have hit a peak of up to 92F in the cap, mid to upper 80s below. Things are now down to the low 80s in the cap, upper 70s below. We're down to around 7 brix, so there's still lots of sugar to go before the new wines are dry. My goal, after pushing the temperature a bit given my small fermentation vessels, is to let things ride easy from here on out to give the wine as much time on the skins as possible. We'll see how long things can go.

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