Wine in two bunches...
The drink of the gods was long forsaken by man. It was around the Roaring Twenties that man became curious and analysed the components of wine.
Analysing the composition of a wine at the time of its conception is almost impossible. The fermentation, its origin, its raw materials generate as many specificities as the terroir and the winemaker. But overall the wine is composed of water, mineral, organic matter and alcohol.
▪ Water comes from the grape. It represents about 2/3 of the volume.
▪ Alcohol: 10% of the remaining third comes from fermentation.
▪ Minerals: negative and positive ions, anions and cations.
In the cations, we find a lot of potassium, metals, copper and iron. These last two come from the grapes and increase throughout the winemaking process.
In the anions, we find our famous sulfur but it comes directly from the grapes. The grape produces a small quantity of it (max 0.3g/l). There are a few traces of phosphorus in the same proportions as the sulphur and finally the chlorine which varies according to the location (stronger in coastal areas) does not exceed 50mg/l.
▪ Organics (proteins, carbohydrates and acids).
For the yeast to take action, the proteins are vital during fermentation. The acids, especially tartaric acid, found in the top come directly from the grape. There are other families of acids, 5 to be precise remain epsilons. I was about to forget the carbohydrates (2g/l) which will slowly disappear during fermentation to become alcohol.
The grapes are always in the process of being transformed, from the vines to the vats. We often hear about "pre-fermentation treatments". This action is the basis for determining the type of wine desired. It is at this moment that the wine is directed towards red, white, rosé, orange. This first choice is made during the crushing or not. This is followed by a maceration or not, then a long, short, light or full-bodied pressing of the grapes. The grapes in this first stage are worked to obtain the acid juice, the sugar and the must.
Then the process of yeasts and bacteria will generate a microbial system of wine making. There are different vinification methods to turn grapes into wine. This is the strength of our diversity.
It is the result of the crushing of the grapes which generates the must which is then placed in so-called fermentation tanks (from 5 to 30 days at a temperature of 16 to 30°). All the yeasts come into action to transform the sugars in the grapes into wine. I don't know if you know Gay Lussac, but it is his formula (Sugar = ethyl alcohol + carbon dioxide) that allows this transformation.
Like eggs on the fire, this stage is always watched over by the little onions, it is on this stage that the taste of the wine will depend. It is necessary to find the balance between a too slow fermentation which will give birth to unwanted elements and a too fast fermentation which will suppress aromas. Everything is in the control of this process: the management of the yeasts and carbon dioxide which will embellish or not the colour of the wine.
This step allows the bacteria to come into action and do their job on the wine. The most important one, the "Oenococcus", will biologically stabilize the wine and allow the reduction of its acidity.
The micro-organisms that allow the fermentation of wine disappear over time and can unbalance the wine. There are several processes to block this phenomenon. Here we are talking about sulfiting or the famous use of sulfur:
▪ it stabilizes
▪ it has an antioxidant effect
▪ it can change the taste of the wine, etc.
The precaution is in its dosage. At high doses, the wine is corrupted and this is strongly felt during tasting and especially the next day, with the "bar" in the head.