Last week we finished our harvest at Collier Falls in Dry Creek Valley, and the focus for our 2012 fruit shifts from grape growing to winemaking.
Before our grapes are even off the mountain and en route to the winery, we're taking steps to assist our winemaking efforts. The first part of this process is fruit sorting. We'll have several people standing by the tractor to remove any leaves or unripe fruit from our half-ton bins so all that remains is the "cream of the crop." We'll repeat this process at the winery on a sorting table to add another layer of scrutiny to our fruit. We're making premium estate wines from Sonoma County, only the best fruit need apply!
Wineries also like to harvest very early in the morning and get the fruit into the winery as soon as possible. You want the grapes to be nice and cool at the start of the winemaking process, because grapes exposed to too much heat can actually begin to ferment before you're ready right in the half-ton bins used during harvest.
After the fruit is sorted at the winery it enters the crusher destemmer. As its name implies, this rather remarkable machine removes stems from the clusters and squeezes the berries giving us the juice that will become wine. Some crusher destemmers actually allow you to set the percentage of how many berries you would like to remain whole, although fermenting with whole berries is not part of our winemaking strategy. The stems become compost, and the juice, skins and seeds are pumped into 10-ton stainless steel fermentation tanks.
If we left everything alone at this point, the native yeasts present on the skins would begin the fermentation process, but we want to delay fermentation and use a winemaking technique called cold soaking. We want the juice to extract extra tannins, color and complexity from the skins before fermentation begins, and cold soaking accomplishes this. The tanks are equipped with glycol cooling systems to keep temperatures low and delay fermentation for anywhere from 2-5 days. In the tank, the skins and seeds rise to the top and are called the cap, so we'll drain the juice from the tank and pour it back over the cap so it filters through the skins and seeds. It's called a pump-over, and we'll do it several times a day during the cold soaking process.
After a few days of cold soaking we're ready to start fermenting the juice. Fermentation occurs when yeast converts the sugars in the juice to alcohol. About 50% of the sugars are converted to alcohol and the remaining 50% is released as carbon dioxide. A wine is considered dry when there is no more sugar left to convert. Since our grapes are harvested with high sugar levels, the native yeast on the skins isn't always strong enough to make our wine completely dry, so we inoculate the juice with more aggressive strains of yeast. We fill a 5-galllon bucket with our juice and add a pound of yeast to the liquid, we then pour this mixture back over the cap. Inoculating the juice in this way 3 to 4 times over the course of fermentation is enough to get the wines of Collier Falls dry and ready for barrel aging. The whole process from the harvest date, to cold soaking, pump-overs, inoculation and fermentation typically takes 2-4 weeks and varies depending on the sugar level in the juice at harvest and the particular grape varietal.
After all that, it will be another 17-22 months in barrels, and at least another year in the bottle before we release the wine. Good things come to those who wait!