Most of the time acid gets a bad rap. When it’s not creeping up your esophagus, it’s melting the Toxic Avenger’s face. It seems it can do no right.
But, lo, not in the world of wine. A well-balanced wine is called so because it balances four primary characteristics. Those are tannins, sugars, alcohol, and acid. Acid is an indispensable part of wine.
But why? From where did it come, and what are its effects? That’s what we aim to explore in this post. At the end, we provide a wine acidity chart so you can easily visualize where wine is on the acidity spectrum. And we provide some tips for finding low acid wines.
Is Wine Acidic?
Yes, every wine is acidic. Though a wine’s acidity level depends on numerous factors. Let’s look at some basics of wine acidity.
Why Is Wine Acidic?
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.
Types of Acid in Wine
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.
Measuring Wine’s Acidity
A wine’s acidity is measured in two ways. First, using the pH scale. And second by a value known as titratable acidity. Both measure acid, but they do it in different ways.
The pH Scale
Acidity is measured on the pH scale, where pH stands for power of hydrogen. The pH scale measures how acidic a water-based solution is. And by “how acidic,” we mean the level of acidity relative to other compounds that affect the acid’s stability and manifestation. The lower the pH number, the more acidic a solution is. The higher the pH number, the more basic (non-acidic) a solution is. Simply put, a wine’s pH level shows how much acid is in a wine. Not how acidic the wine tastes. Though, more often than not, low pH results in acidic tastes.
One important thing to note is that the pH scale is logarithmic. That means each whole number pH value below 7 (which is neutral, aka water) is 10 times more acidic than the preceding whole number. For example, a wine with a pH of 3 is 10 times more acidic than a wine with a pH of 4.
Where pH measures the relative internal acidity of a solution, titratable acidity measures the overall total acidity of a solution. And where pH levels are measured on the pH scale, titratable acidity is measured as a percentage of the wine. The level of titratable acidity in a wine, known as its titration, measures how strong the acid in wine tastes.
The difference, then, is that pH is measuring whether or not acid is in the wine. Titration is measuring how tart the acid makes the wine.
Wine Acid Levels
As we’ve seen, there are a few different factors that determine a wine’s acidity. And those factors are typically independent of each other. Just because a wine grape is from colder climes doesn’t mean a winemaker won’t add acid to it. Even cooking wine is acidic. The acidity of a wine depends on that wine’s individual identity and journey. But we can draw some general conclusions based on grape types and winemaking processes.
Is Red Wine Acidic?
Yes, red wine is acidic. Average pH levels for red wines are between 3.5 and 3.8. The tartration level (% of the wine that is acid) of red wine is around .6 to .8%. This makes red wine less acidic than white wine, as a whole. Though less acidic than white wine, when drinking red wine you'll also want to learn how to remove old red wine stains or pick up a wine stain remover.
Is White Wine Acidic?
Yes, white wine is acidic. The average pH levels for white wine are 3.1 to 3.4. And white wine’s tartration level is typically between .7% to .9%. This makes white wine more acidic than red wine, generally.
For a little context, grape juice has a pH level of about 3.3, apple juice between 3.3 and 4, and orange juice 3.3 to 4.2. And lemon juice has a tartration level of about 5%.
Note that, as a whole, white wines are more acidic than red wines. That’s one of the reasons white wines have a lower average wine serving temperature.
Low Acid Wine: Least Acidic Wine
Lots of folks out there with GERD, acid reflux, ulcers, or other related conditions have to stay away from acid. That can make finding wine a challenge. You should of course check with your doctor about what acid levels are acceptable for you. These tips are not meant to serve as or replace a professional medical opinion.
Low Acid Red Wine
Pay most of your attention to the climate the wine is grown in. Wines grown in warmer parts of the world usually have less acid than wines grown in cooler parts of the world. (Sadly, cold isn’t the blanket answer here. Freezing wine isn’t the solution to removing a wine’s acid.) If you had to choose between a California cabernet and a French Bordeaux, go with the California wine. Apply that geographical decision making to any red wine and you’ll probably end up with the lower-acid version of the varietal you’re after. Be on the lookout for wines from California, Australia, southern Italy, and Argentina.
In terms of wine grapes themselves, the lowest acid red wine grapes tend to be cabernet sauvignon, merlot, and grenache.
Low Acid White Wine
Like reds, the climate a white wine’s grapes are grown in is paramount to its acidity. Always be on the lookout for warm-climate grapes over cooler-climate grapes. A chardonnay from California, for example, is a better choice than a French Chablis. Gravitate toward wines from California, Australia, southern Italy, and Argentina, just like you would with reds. And always choose a warmer climate over a cooler climate.
From a grape perspective, the white wine grapes that usually have the lowest acid content are chardonnay, viognier, and gewurztraminer.
Food and Wine Pairing
So how does this all play out with wine and food pairing? Let’s look at what acid in wine really tastes like and what types of foods complement it. Acidity doesn't affect the calories in a bottle of wine, so don't expect that choosing a less acidic bottle will offset a heavier meal.
What Does Acidic Wine Taste Like?
Put a drop of lemon juice on your tongue. That’s what a pH level of around 2 and a total acid content of 5% tastes like. And it’s a good representation of how your mouth and tongue behave when they encounter the acid in wine. You start salivating. Your muscles clench and you start puckering. In fact, those physical reactions can happen just at the thought of lemon juice.
Wine has a higher pH level and a fraction of the tartration level as lemon juice. But the physiology of your reaction to it is the same. The next time you take a sip of wine, try to isolate that reaction in your mouth. That’s the acid.
If you want to get deeper in the weeds, each acid type has its own flavor profile. Tartaric acid tends to be the hardest, most aggressive acid. Malic acid typically has notes of young green fruit. And lactic acid lends a funkier, creamier aspect to wines.
What Foods Pair Well with What Levels of Acid in Wine?
“Well” is subjective. There are two primary ways of pairing wines with food. One is to contrast flavors, and the other is to use like-upon-like and complement flavors.
Contrasting Acidity with Wine Pairing
When combining contrasting flavors, the goal is to create a round flavor that hits on many of the five basic flavors. Those are sweet, sour, bitter, salty, and umami. As such, sweet, bitter, salty, and umami flavors do well when paired with the sour sensations of acidic wines.
A great example of this is pairing cheese with wine. Cheese, in general, is salty and creamy. When paired with acidic wines, the cheese is cut through elegantly. The contrasting flavors swirl around each other in delicious equilibrium.
To this end, enjoy acidic wines with combinations of the other five basic flavors. Watch your pairings become far more than the sum of their parts.
Complementing Acidity with Wine Pairing
Another food and wine pairing strategy is to enjoy similar flavors together. A good example of this would be a summer salad (like an apple cranberry salad) paired with a dry white wine. The acidity of the white wine enhances the acidity of the fruits. They don’t overpower each other, they fill in each other’s gaps. The flavor becomes round but it’s not the roundness of the five basic flavors, it’s the roundness of the completion of one of them.
Try pairing whitefish with a Central Coast California grenache and you’ll get the idea.
Wine Acidity Chart
We put together this handy wine acidity chart to help visualize where wine is on the acidity spectrum compared to stuff you’re already familiar with. Each number is an average. And there are, of course, outliers. It’s meant only to be a general representation to give you context for the pH levels of wine. Also note, oxidized wine has a higher level of acidity due to chemical reactions.
Is Wine Acidic? Yes.
In the grand scheme of things, wine is just about as acidic as your average fruit juice. For anyone looking for the most basic wine possible, you can find some low-acid reds that get up to about 4.5 pH. Those will typically be grenaches from warmer climates. But it depends a lot on the winemaking techniques and aging processes. It’s hard to make a blanket statement about wine acidity because of all the variables that go into it.
If you’re interested in the many aspects of wine care, we’ve got some great resources about wine storage. Things like how light affects wine and how to find the best wine storage furniture for your collection. These can all help you prevent and deal with bottle shock in wine.
Wine is a precious, delicate, often complicated thing. It’s a consistently changing substance. In that sense, it’s alive. And the more you know about, the easier it is to care for.