Almost all of the aromas and flavors of wine come from chemicals called phenols in the grapes used to produce it, though barrel aging can also have a significant impact. This writeup contains the names, locations, and qualities of the grapes commonly used to make red and white wines.

Red wine grapes

The most important ones

  • Cabernet Sauvignon--This is the king of red wine grapes. Its high tannin content and low yield make it it suitable for dark, complex, cellarable wines. The cabernet sauvignon is the dominant grape in wines made in the Médoc region of Bordeaux. It is also popular in California, Chile, Australia, South Africa, and New Zealand.
  • Merlot--This grape has fewer tannins than the cabernet, which makes it less durable. Its softer nature has its own appeal though. It is usually blended with the cabernet in the Médoc to add complexity and balance. In the eastern regions of Bordeaux such as Saint-Emilion and Pomerol it is the dominant grape and makes world-class wines. California and Chile are other top producers.
  • Pinot noir--the grape of red Burgundy. Some winemakers in Oregon are also testing their luck with it. The pinot noir is almost never blended with other grapes. Its wines are low in tannins and a bit pale in color. The best example I've had was chalky and mineral-laden.
  • Syrah--considered the most noble grape of the Rhone. The syrah is also very successful in Australia, where it is called the shiraz. Wines made from the syrah are tannin-rich, spicy, dark, and a little bitter.
  • Zinfandel--The zinfandel is successful almost exclusively in California. It makes zesty reds that are far better than their white zinfandel counterparts.

The next most important ones

  • Cabernet Franc--A small amount (5-15%) of this grape is added to most Bordeaux reds to enhance aroma. I have had a cabernet franc-dominated California red wine that was every bit as complex as most high-quality cabernet sauvignons, but such wines are rare.
  • Gamay--the grape of Beaujolais. It is fruity, simple, and pleasant. The gamay isn't considered very noble but Beaujolais is quite popular arnd fun to say.
  • Grenache--A grape that, along with the southern Rhone region, is gaining popularity. It yields peppery, somewhat harsh wines.
  • Nebbiolo--This grape is used to make the world-famous Italian reds of Barolo and Barbaresco. It yields incredibly long-living, tannic wines.
  • Sangiovese--the grape of Italian Chianti. It makes relatively simple wines that wine snobs disparage.
  • Tempranillo--an outstanding and unusual grape of the Rioja and Ribera del Duero regions of Spain. This grape can yield a whole range of weird flavors like tar, petroleum, tobacco, and various minerals. I think it's underrated.

Less noteworthy red wine grapes

White wine grapes

The most important ones

  • Chardonnay--The chardonnay is easily the most popular white wine grape. It often tastes like citrus and smoky oak and cream due to barrel aging. Most experts consider the best examples of chardonnay to be those of white Burgundy, but the chardonnay makes successful, world-class wines in California and the rest of the world also.
  • Riesling--This grape is famous for its use in the partly sweet wines of Alsace and Germany. It usually is pretty tart and acidic.
  • Sauvignon Blanc--I think this grape is growing in popularity as people look for alternatives to chardonnay. The best examples are from the central Loire region of France--Sancerre and Pouilly-Fumé. It is also used in Bordeaux sweet wines like those of Sauternes. New Zealand seems to churn out very good sauvignon blanc wines these days. The grape can taste a bit vegetal and tart. Oaked Californian sauvignon blancs are often referred to as fumé blancs, a term coined by Robert Mondavi.

The next most important ones

  • Gewürztraminer--pronounced guh-vort-strah-mee-ner. This grape makes fun wines, if only because of the name. Wines made from this grape have a very distinct smell of flowers and lychees. The best examples are definitely from Germany and Alsace.
  • Sémillon--a noble Bordeaux grape used in sweet wines. The most famous example is Chateau d'Yquem in Sauternes, which uses 80% sémillon. The thin skin of the sémillon makes it vulnerable to the noble rot that results in luscious sweet wines.

Less noteworthy white wine grapes