Fermentation is affected by several factors like temperature. It can only take place between 5ºC and 38ºC. The fermentation of white wines takes place at a lower temperature, between 8ºC and 14ºC; and red wines ferment between 25ºC and 30ºC. The fresh and aromatic flavors are best achieved with lower temperatures. Other things that affect fermentation are the levels of sugar, the acidity levels, the presence of micro nutrients like vitamins and even the airing of the barrel.