Understanding Acidity in Wine
In this post, we'll explain more about how acidity plays a part in your wine and how to anticiapte acidity in wines for your future tastings! Let’s use the PH scale to understand the acidity of wine. Did you know wines have a PH of about 2.7 - 4.5. Lemon has a pH level of around 1. Coca Cola is at 2.5. White Wines are at 2.7-3.5 and Red Wines are at 3.5 - 4.5. Winese ARE pretty acidic!
To have an idea on how acidity feels like: Imagine taking a bite of a wedge of lemon, feel how your entire mouth salivates and puckers? Remember this feeling the next time you take a sip of wine. Without acidity, wine can feel and taste flat and flabby. That’s what acid does so well — it balances flavors.
If you're surprised that sweet whites are more acidic than regular whites, don't be! Sugar mask your sensation of acidity. For reference, coca cola and champagne have the same level of acidity but the puckering sensation is a lot more intense when drinking a glass of bubbles isn't it!
Types of Acid in Wine
(Skip this section if you don't wanna get too technical)
There are four primary types of acid found in wine. They’re tartaric acid, malic acid, citric acid, and lactic acid. Tartaric acid and malic acid account for about 90% of the acid in wine. There are many great books out there to learn about wine that can break down the acidity levels in common wine varietals.
Tartaric Acid In Wine
Tartaric acid is the primary acid in wine grapes. It’s probably the most durable acid in a wine, and it resists much of the effects of other acids. That’s why it’s called a fixed acid. That makes it one of the most important parts in stabilizing a wine’s ultimate color and flavor profile. The concentration of tartaric acid depends a lot on a grape’s growing climate, soil content, and the grape variety itself.
Interestingly, only about half the tartaric acid in a grape is soluble in the alcoholic mixture that becomes wine. The rest tends to attach itself to pulp debris, tannins, and pigments. Sometimes that undissolved tartaric acid precipitates and crystallizes in the wine. That’s what “wine diamonds” are. Those little broken-glass-looking shards you sometimes find in wine. They’re crystallized tartrates that have become unbound from other free-standing molecules in wine. They’re completely harmless.
Malic Acid In Wine
Malic acid is the second most prominent type of acid in wine grapes, and is an essential part of a healthy, functioning grape vine. It’s in virtually all fruits and berries, and tends to show up in wine as a young fruit—typically apple—flavor. Malic acid is metabolized by grape vines as they age, which means it decreases as vines grow older. The concentration of malic acid in a wine depends mostly on the grape variety used. If malic acid is too high, winemakers can engage in a process called malolactic fermentation (MLF). MLF converts some of the malic acid to the more mild lactic acid.
Lactic Acid In Wine
When a wine has a lot of lactic acid, it begins to have a buttery, creamy mouthfeel. Lactic acid is the primary acid present in a lot of fermented products, like yogurt, kefir, sourdough bread, and sauerkraut. During the winemaking process, a winemaker may choose to add lactic acid bacteria. Those bacteria will convert malic acid and sugar into lactic acid through MLF, which adds a softer, creamier bent to the overall flavor profile. That can enhance a wine’s complexity and roundness. But, beware, too much lactic acid can cause the dreaded red wine headache, particularly among people who suffer from wine allergies.
Citric Acid In Wine
Citric acid has a minor presence in wine, but a noticeable one nonetheless. The quantity of citric acid in wine is about 1/20th that of tartaric acid. It’s mostly added to wines after fermentation due to yeast’s tendency to convert citric acid to acetic acid. It has an aggressive acidic taste, is often added by winemakers to increase a wine’s total acidity, and should be added very cautiously.
Wine is acidic mostly because grapes are acidic, and wine is made from grapes. Though how acidic a wine is depends on a number of things:
The climate in which its grapes are grown. Grapes grown in warmer climates have less acid than grapes grown in cooler climates.
How ripe the grapes are when the winemaking process begins. Riper grapes have higher levels of acidity.
How long a wine is aged. Aged wines often undergo a process called malolactic fermentation. During that, a wine’s malic acid converts to lactic acid and lowers a wine’s total acidity content.
If a winemaker adds acid during the winemaking process. Acid can be added during winemaking or after primary alcohol fermentation to affect a wine’s colors, flavors, and aromas.
When wine grapes are still green, they have very high acidity. As they ripen, the acidity tapers down, and the sugar in the grapes increases.
When the grape is perfectly sweet and ripe, it also has to possess enough acidity to make a great wine. This is where climate comes in. A region that produces wines with naturally higher acidity will have either cooler nighttime temperatures or a shorter growing season.
The cool nights and cold weather stops the grapes from losing their acidity. In a region with a shorter growing season, there’s also the possibility that the grapes never quite get ripe enough, which results in both more tart and more herbaceous tasting wines. Wines from Germany, France, U.K are such examples.
Warmer climates will often produce wines with lower acidity. The high temperatures found in regions such as California, South Africa, and Australia cause grapes to ripen rapidly, reducing the naturally occurring acids and increasing the sweetness of the grapes and resulting wine. This is why tartaric acid is most commonly added to wines grown in warm climates. (Tartaric acid plays a key role in the stability of wines and influences the taste, colour and odour of the final product. )
While all wine falls between 3-4 on the pH scale, pH is a logarithmic scale, so theoretically, a wine with a pH of 3 is ten times more acidic than a wine with a pH of 4.
If we were to to place wines on the PH scale ranging from least acidic to most acidic, it would look something like this.:
- Low-acid reds such as late-harvest, warm-climate wines made from sweet, ripe grapes, or red wines that have been aged, causing them to lose their acidity naturally in the bottle.
- Full-bodied red wines, such as Cabernet Sauvignon.
- Medium-bodied red wines, like Sangiovese.
- Lighter-bodied, higher-acid wines, such as Pinot Noir and Grenache.
- Full-bodied white wines, such as Chardonnay.
- Medium-bodied white wines, like Sauvignon Blanc or Chenin Blanc
- Light-bodied, highly acidic wines like Riesling, or brut sparkling wine and Champagne are some of the lowest on the pH scale.
A good balance of acidity is essential for a great bottle of wine. While you may not purposely seek out highly acidic flavors, all wine has some level of acidity. These are mostly derived naturally from the grapes themselves, while some winemakers add tartaric acid to their wine prior to fermentation to balance the sweetness.
If you dislike highly acidic flavors, go for a full-bodied red wine. Remember to favor wines from warmer climates, which are more likely to boast those sweeter, fruitier flavors. And remember to pay special attention to the puckering of your mouth when you taste.
On the other hand, if you love crisp, tart flavors, opt for light-bodied white wines from cooler climates, such as Western Europe. Riesling and brut sparkling wines are always a good bet!