But grapes are not all the same: besides the taste of grapes varying depending on the soil, climate, orientation to the sun etc., there is also the judgement of

But grapes are not all the same: besides the taste of grapes varying depending on the soil, climate, orientation to the sun etc., there is also the judgement of when to harvest. Once in harvest season grapes can approach and then pass the desirable sugar level in a matter of days. During the winemaking process there are many variables that cannot be codified from season to season because of variation in the grapes, such as increasing or decreasing acidity (and how), fermentation temperature, adjusting tannins, and probably more.