It is in the wine fermentation that the magic begins ... and this is not new. The wine fermentation - or rather, grape must or juice - is a process that has thousands of years. In Europe there are records wine traces found in Georgia in an amphorae that dates back to 6,000 years BC. This means that grapes have been fermented for at least 8,000 years.
The first known winery dates back to 4,100 years BC and was found in the city of Areni, in Armenia, where wine is still produced. In fact, the story goes that since obsidian stone was used for tools, that man makes wine fermentation. In other words, this process goes back to the Stone Age.
So, what is wine fermentation? Alcoholic fermentation is understood as the biochemical process during which yeasts transform the sugars present in the must into alcohol. During this process there are more results in addition to ethanol, namely the formation of carbon dioxide and other by-products that are essential in wine production, since they contribute considerably to the chemical and sensory composition of the final result.
Wine fermentation can be spontaneous or induced. In the case of natural wine or spontaneous fermentation, little or nothing is added to the must, the grape fermentation being made by the indigenous yeasts of the vineyard or cellar where the wine is produced.
In the most conventional way, fermentation is usually induced by the addition of selected yeasts that the winemaker has chosen and whose purpose is a specific result and outlined by whoever produces the wine.
The wine fermentation process consists in transforming the sugars present in the grapes into alcohol. After the grapes are harvested, they are transported to the cellar where the grape fermentation process begins. The winemaker has several options in the way he will produce and transform the grapes into wine, but basically, he has to crush the grapes to obtain the grape must or juice, which at that moment is just sugar and water, with all the precursors that will determine the wine quality.
Once the must is obtained, alcoholic fermentation begins, in which the yeasts transform the sugars into ethanol. And so, the fermentation process ends, which is simple. The complexity of producing a good wine starts in the vineyard. Once in the cellar, it is a question of controlling all the phases of wine fermentation and carefully monitoring so that there are no deviations during the process, it being a wine with natural fermentation or a fermentation with selected yeasts.
Wine fermentation stops naturally.
When? When the fermentable sugars run out in the must or if the fermentation conditions are no longer favorable to yeasts. However, there are several ways to stop wine fermentation, including cooling the must to temperatures at which yeasts cannot ferment.
There’re even wines, such as late harvest, in which fermentation stops in the middle, due to the high concentration of sugars still to be fermented. In this case, together with the alcohol already produced, sugars limit the life of the yeasts that end up dying before the end of alcoholic fermentation, resulting in a sweet wine.
Of these and other half-fermented wines we will talk about in an upcoming article on the winemaker's blog. Until then.