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Jul. 15, 2020 | Wednesday
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Wine Thang: How fermentation creates wine
The fermentation process. (File photo)

The staff of Ravine Winery share their expertise and offer a brief explanation about an aspect of wine in this regular feature. So, whether you’re an expert oenophile or a newbie just finding your way around wine country, we trust you’ll enjoy. Cheers!


The fermentation of wine is generally juice (sugar) + yeast = wine (alcohol). 

The white wine fermentation process differs from that of red. White grapes are harvested and destemmed. The grapes are pressed to extract all juices and the skins discarded. The sweet juices are now introduced to yeast, which will begin to consume the natural sugars, converting it to alcohol.

A natural byproduct of fermentation is also the creation of heat and carbon dioxide (CO2). At this point, the carbon dioxide is allowed to escape to the heavens, this is known as the “Angels Share.” 

The fermentation tanks are wrapped in what’s referred to as a “cold jacket,” allowing the wine to be cold so the white wine remains fresh and fruity. Red wines don’t mind the temperatures being a little warmer during fermentation so the “cold jackets” are not necessary.

The main difference with fermenting reds is that the grapes ferment while the skins are intact so that we can take from them tannin, flavour and colour.

The CO2 causes the skins to float, so the wine and skins have to be “punched down” to ensure the skins are continually integrated with the juice. Red wines ferment for about two to three weeks. Fining and filtering is a discussion for another day!