Become a wine expert (part 6): Acid
Acid is an important wine characteristic to pay attention to. White wines with high acid (Sauvignon Blanc, Riesling, etc.) tend to taste crisp and refreshing. The acid in the wine adds a "mouthwatering" sensation on the finish. Wines with too little acid feel underwhelming in the mouth and taste vapid. Wines with too much acid can be sharp, prickly, and tend to produce a sour sensation in the mouth. Balance, just like most wine characteristics, is the key to acid. Some wines have so much acid (Riesling) that they are often-times finished with residual sugar to tone down the tartness (similar to how sweet/sour candies work). Wines with a lower pH will have stronger acids.
Try it at home: For white wine, grab a bottle of Sauvignon Blanc and a bottle of Chardonnay. If you would rather try it with red, grab a bottle of Oregon Pinot Noir and a bottle of Merlot from California. First try the Sauvignon Blanc (or the Pinot if you are trying it with red) focusing on how it feels in your mouth - specifically the tartness on the sides of your tongue. Next, try the Chardonnay (or Merlot), again focusing on how it feels in your mouth. The high-acid wines (Sauvignon Blanc and Oregon Pinot Noir) should produce a mouthwatering effect and be more tart on the palate. The lower acid wines (Chardonnay and California Merlot) should be quite a bit softer on the palate.
Types of Acid and what they taste like:
- Tartaric acid flavor - harsh, sour, tart. Tartaric acid is probably the most important acid as part of wine's chemical composition. Tartaric acid is the reason "wine diamonds" sometimes appear in wine. This happens because some wines are not cold stabilized and at low temperatures, tartaric acid can turn into potassium bitartrate crystals which look like little diamonds (or broken glass) in the bottom of a wine glass.
- Malic acid flavor - green apples, crisp, refreshing. Malic acid can be turned into lactic acid during malolactic fermentation which turns crisp, young-tasting wine into creamier wines.
- Citric acid flavor - Lemon, lime. Citric acid is found in very small levels in wine grapes.
- Acetic acid flavor - Vinegar. Acetic acid is creates an off-odor in wine and can be a way to detect spoiled wine. If wine is exposed to oxygen, Acetobacter bacteria can turn ethanol into acetic acid - essentially reducing wine to vinegar.
- Butyric acid flavor - Spoiled milk, rancid butter. An off-odor in wine that usually means the wine is spoiled. Bacteria is the culprit behind Butyric acid in wine.
- Lactic acid flavor - creamy, soft, milky. Lactic acid is generally enhanced during a winemaking technique called malolactic fermentation - which is very commonly used during the production of creamy Chardonnay.
- Succinic acid flavor - Sweet, fruity. Succinic acid is a by-product of fermentation and found in higher levels in red wines.