Red wine is a type of wine made from dark-colored grape varieties. The color of the wine can range from intense violet, typical of young wines, through to brick red for mature wines and brown for older red wines. The juice from most purple grapes is greenish-white, the red color coming from anthocyan pigments present in the skin of the grape. Much of the red wine production process involves extraction of color and flavor components from the grape skin. Varieties The top 20 red grape varieties by acreage (listed alphabetically) are: Alicante Henri Bouschet Barbera Bobal Cabernet Franc Cabernet Sauvignon Carignan Cinsaut Malbec Douce noir Gamay Grenache Isabella Merlot Montepulciano Mourvèdre Pinot noir Sangiovese Syrah Tempranillo Zinfandel The top 30 red grape varieties by acreage (listed alphabetically) are: Aglianico Blaufränkisch Bordô Carménère Castelão Concord Corvina Veronese Criolla Grande Croatina Dolcetto Dornfelder Marufo Mencía Black Muscat Nebbiolo Negroamaro Nero d'Avola Pamid Petit Verdot Pinot Meunier Pinotage Prokupac Ruby Cabernet Saperavi Tannat Tinta Barroca Touriga Franca Touriga Nacional Trincadeira Zweigelt Production Grape processing The first step in red wine production, after picking, involves physical processing of the grapes. Hand-picked or machine-harvested grapes are usually tipped into a receival bin when they arrive at the winery and conveyed by a screw mechanism to the grape-processing equipment. Destemming and crushing On arrival at the winery there is usually a mixture of individual berries, whole bunches (particularly with hand-picked grapes), stems, and leaves. The presence of stems during fermentation can lead to a bitter taste in the wine, and the purpose of destemming is to separate grapes from the stems and leaves. Mechanical de-stemmers usually consist of a rotating cage perforated with grape-sized holes. Within this cage is a concentric axle with arms radiating towards the inner surface of the cage. Grapes pass through the holes in the cage, while stems and leaves are expelled through the open end of the cage. After destemming, the grapes are commonly lightly crushed. Crushers usually consist of a pair of rollers, and the gap between them can usually be regulated to allow for light, hard or no crushing, according to the winemaker's preference. The mixture of grapes, skins, juice and seeds is now referred to as must. The must is then pumped to a vessel, often a tank made of stainless steel or concrete, or an oak vat, for fermentation. In common with most modern winemaking equipment, destemmers