Acid in wine, that can’t be a good thing, right? Well, it turns out that you can’t make a good wine -- particularly white wines -- without the right acid level. Acid, along with tannin, alcohol, and sugar is one of the elements that provides “structure” to the wine -- the wine’s framework that’s embellished by aromas and tastes. In a good wine, all four elements will be in balance.
- Acid constitutes less than one percent of wine volume, but helps wine taste fresh and crisp as well as acting as a preservative. High acid wines are generally “food friendly” – the acid makes you want a bite of food, which makes you want another sip, which makes you want another bite . . .
- We perceive acid as a sour taste. If you want to “get” acid, take a drink of unsweetened lemon juice. That sour, mouth puckering taste is acid. You may experience it as a tingling sensation on the sides of your tongue.
- A wine with too much acid is unpleasantly sour and mouth puckering; with too little acid it will be dull and uninteresting. The trick is to have just the right amount so that it doesn't stand out. Acid also balances sweetness -- the sweeter the wine, the more acid is needed to keep it from being unpleasant. For example, a high-quality Sauternes will be very sweet but pleasant because of the offsetting acid.
- To understand the acid/sugar balance, think about a fresh grapefruit – by itself it can be almost too tart to eat, but add a little sugar and you’ve got something pretty nice.
Nothing ruins a good glass of wine like a chemistry lesson, so we’ll skip the technical stuff and just touch on the highlights.
- There are several types of acids in wine, including tartaric acid and malic acid (think of green apples), and each has different characteristics. There are a couple of different ways to measure acid strength in a wine, including pH and TA. Heard enough? I thought so.
- One acid-related term that you’ll hear a lot about is “malolactic conversion” (a.k.a., malolactic fermentation or malo), a process where harsh malic acid is converted to softer lactic acid. It makes for a richer, softer wine, and almost always occurs in red wine. Sometimes a winemaker will intentionally block malo in a white wine so that it will be crisper – for example, a Chablis.
Here’s how acid in a wine is described:
- “Green” or “tart” – a wine that’s too high in acid. It will be sour and unpleasant.
- “Crisp” – a wine with noticeable but not unpleasant acid. This would include, for example, most New Zealand white wines; Loire Valley whites such as Vouvray and Sancerre; Alsatian whites; and many Burgundy whites.
- “Flabby” or “Flat” – a wine that’s too low in acid. The wine seems dull. This often occurs in hot climates. Flabby can also describe humans during high calorie, low exercise Covid lock downs. But that’s another story . . .
Acid levels vary significantly among different grapes and regions.
- Generally, cool climate grapes tend to be more acidic, and hot climates less so. Regions that have significant temperature drops in the evenings tend to preserve grape acid levels. Regions such as the Texas Hill Country, that don’t have significant temperature drops, have trouble maintaining acid levels.
- Some grapes have naturally high acid levels, including Sangiovese (g., Chianti), Pinot Noir (e.g., Burgundy and Willamette Valley), Albariño, Muscadet, Chenin Blanc (Loire Valley) and cool climate Sauvignon Blanc (shown above). There are also switch hitters, such as Chardonnay, which is capable of high acid levels in cool regions such as Chablis, but lower acid levels in warm regions such as much of California.
- Winermakers sometimes add acid to a wine if the natural acid level is too low.
For our wine of the week, let’s look back at several of the high acid wines that we’ve reviewed in the past. Those are shown on the highlighted links above – click on the link for our review.
Cheers!