Simply put, wine is an alcoholic beverage made from grapes. In order for alcoholic fermentation to take place you need a suitable yeast strain and sugar. In the case of wine, the sugar is provided naturally from the juice of whichever variety of grape you decide to use. The yeast can be bought ensuring a stable and repeatable fermentation or the winemaker can use the naturally occurring strains that are present in the winery.
Unlike the grapes we eat, wine grapes (Latin name: Vitis vinifera) are smaller, sweeter, have thick skins, and contain seeds. There are over 1,300 wine grape varieties used in commercial production but only about 100 of these varieties make up 75% of the world's vineyards.
Today, the most planted wine grape in the world is Cabernet Sauvignon ("cab-err-nay saw-vin-yon").
The yeast eats the sugar and produces alcohol and carbon dioxide, generally the CO2 is allowed to dissipate but can be trapped to produce a sparkling wine (we will discuss this further in the next post).
Generally speaking, grape juice is a clear liquid, the colour is derived from soaking this juice alongside the skins of the grape, often during fermentation as the alcohol acts as a solvent. Therefore, you can produce a white wine from red grapes (for example Champagne) but you can’t produce a red wine from white grapes. There are exceptions to this (teinturier grapes) but they aren’t particularly common. Rosé is generally produced from a shorter contact time with the red grape skins and orange wine is another term for skin contact white wine where colour has been extracted from the skins (although this can derive from oxidation or aging).
There are a lot of options for the Winemakers in this process so we will dive into greater depth in later posts!
(David Bosanquet, Manager/Somm - Restaurant Santino)