Red wine is a type of wine that contains pigments from the skins of grapes. Most grapes whether the skins are red or white have clear juice. Those that do not are called teinturier -- Alicante Bouchet and some hybrids have red juice. Red wine ranges in color from pale pink to opaque purple-black or even blue (in low acid red wines).
As red wines age, they do so from the outside in-- pour a glass of red wine and tilt the glass at a 45 degree angle. The thinnest part of the wine at the edge of the glass (called the rim) desaturates first, becoming clear, then paler shades of red creep into the rim and move toward the core (the deepest part of the wine in the glass), eventually turning amber with a faint brick red core. As they age, red wines go from dark red or purple to bricky red or amber. Due to their high pigment content, red wines have a more tactile feel in the mouth, and can described as velvety when the wine is concentrated.
Most red wines spend time in oak barrels, as the flavors of the wood work well with common flavors in red wines. Some, like Cabernet or Merlot, are fermented and aged competely in new wood, which promotes gentle oxidation through the pores of the wood, and softens grape tannins. Some lighter reds are aged in stainless steel, such as Beaujolais Nouveau (made from the Gamay grape) or Rhone wines made from Grenache, which has the tendency to oxidize quickly. In many parts of the world, different red grapes are blended together to highlight their strengths and play down their weaknesses. In Bordeaux, for example, poor weather around harvest time led to the planting of many kinds of red grapes that ripen at different times, which meant that even in inclement weather, some wine could be made. Today, five red grapes can legally be grown in Bordeaux according to French law: Cabernet Sauvignon and Cabernet Franc, Merlot, Petite Verdot and Malbec. In the Rhone, the lighter, prone to oxidation Grenache is typically blended with the more sturdy Syrah and Mourvedre (which resists oxidation) to make Chateauneuf-du-Pape.
Red wines are natural pairs for red meat of any sort, but lighter red wines can pair well with chicken, game birds or fish. In Italy, it is common to drink red wine with pasta (in the north) and tomato sauces (in Tuscany). Red wine is difficult to pair with shellfish, though, as their high iodine levels can make red wines taste metallic.