After harvesting, the grapes are crushed to release the must (grape juice). Crushing simply means to break the berries skin, allowing juice and pulp to be exposed and the yeast to start fermenting. Maceration with skins is not desired in white wines.
Pressing separates the liquid from the solid. White wines are pressed immediately to avoid contact with skins, stems and seeds rich in tannins. This is the major difference between white and red wines.
Alcoholic Fermentation is the transformation of grape juice into wine, of sugar into alcohol.
Sugar + Yeast = Alcohol + CO2 + Flavors.
Fermentation in stainless steel does not add ekstra aromatic compounds (neutral vessel). Fermentation in oak barrels adds Secondary flavors.
Alcoholic Fermentation creates heat. Red wines are fermented at higher temperatures (20-32°C, 68-90°F) to extract color and tannins. Rosé and white wines are fermented at lower temperatures (12-22°C, 54-72°F) to maximize the fresh fruit aromas.
Malolactic Conversion or Fermentation (MALO or MLF) is optional and converts Malic Acid into Lactic acid. The wine becomes more stable, flavor changes and the acidity is slightly reduced.
MLF transforms the aromatic compounds from citrusy, green, refreshing and crispy to buttery, lactic, nutty, yeasty, oaky, sweaty and earthy.
Maturation refers to a period of time after Fermentation and before Bottling. During this time the wine goes through changes: blending, MLF, clarification, stabilization etc.
The wine color progressively changes to darker tones: from green to yellow straw to gold and the grape-derived aromas fade.
Aging refers to the changes in wine after bottling.