– Part Three –
Wine before it’s beautifully bottled and poured into your glass is not all that romantic. Leaving old grape juice to just hang around and ferment may sound kind of crude, but it’s necessary.
Fermentation needs to happen in order to create the alcohol that makes wine taste better than plain old grape juice. This occurs as yeast consumes the sugars present in the juice, creating alcohol and carbon dioxide. There is quite a pungent yeasty-grapey smell during fermentation but this lets you know that the yeast is hard at work turning grape juice into wine.
During this primary fermentation, the must goes through some pretty intense bubbling as the yeast is highly active converting sugars into CO2 and alcohol.
For about 10 days, there was a slight grape-funk aroma in the house. As the sweet dark liquid bubbled away in its bucket, I thought to myself, Ah…I love the smell of fermenting grape juice in the morning.
Stabilizing and Clearing
After two weeks, the fermentation ended and the funk in the house was pretty much gone. The yeast did its job, turning the grape juice into wine. My nose could detect the alcohol. At this point, the wine was cloudy and needed to be cleared before bottling.
If you think about the wine you drink, it is always very clear, maybe even brilliant. This is a desirable quality so it is necessary that the wine be prettied up through a process called fining.
Fining is done in order to remove the stuff from fermentation that makes the wine cloudy. This stuff includes spent yeast cells and solid compounds from fermentation. While the dead yeast cells could eventually fall out of the wine and settle to the bottom of the carboy on its own, this would take a very long time and still may not result in a clear wine.
So here’s where a little chemistry helps winemaking along. In order to clear the wine, positive and negatively charged clearing agents are added to attract the unwanted particles. These attracted particles collect to form heavy clumps that quickly drop to the bottom, leaving clear wine. The clear wine is then siphoned from the sediment called racking.
I siphoned the clear wine from the fermenter bucket careful not to allow any sediment into the carboy. A carboy is a large glass bottle that looks like the bottles once used to fill old water coolers. To preserve the wine, I added the sulphite as well as potassium sorbate which neutralized the yeast so no further fermentation would occur in the bottle. Adding the clearing agents, I moved on to degassing the wine.
This article is a Green Thumb AdventureTM series – a collection of documentary articles about finding your inner gardener and winemaker. If you have any similar experiences, thoughts or comments, chime in! Share with us. We hope you enjoy.
— Heidi Butzine
Senior Editor, Wineopolis Press