There are five basic stages to the winemaking process which begins with harvesting or picking.

After the harvest, the grapes are taken into a winery and prepared for primary ferment. Red wine is made from the must (pulp) of red or black grapes and fermentation occurs together with the grape skins, which give the wine its color.

After the primary fermentation of red grapes, the free-run wine is pumped off into tanks and the skins are pressed to extract the remaining juice and wine. The press wine is blended with the free-run wine at the winemaker's discretion. The wine is kept warm and the remaining sugars are converted into alcohol and carbon dioxide.

The next process in the making of red wine is malo-lactic conversion. This is a bacterial process which converts "crisp, green apple" malic acid to "soft, creamy" lactic acid softening the taste of the wine. Red wine is sometimes transferred to oak barrels to mature for a period of weeks or months; this practice imparts oak aromas and some tannin to the wine. The wine must be settled or clarified and adjustments made prior to bottling.

More Info: en.wikipedia.org