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All About Sour Grapes

Grapes are a deliciously sweet fruit and are widely distributed and sold for that reason. But, that’s not always the case. Sometimes, grapes can be sour, whether it be a bitter variety of grape or a grape that was picked before it was ripe. This may seem like a case of bad quality grapes, but there are many neat uses for sour grapes in winemaking and cooking.

Why, you ask? Keep reading to learn all about this fascinating side of one of your favorite fruits!

A hand holds sour grapes.

What Causes Sour Grapes?

There are several factors that can contribute to creating sour grapes. I’m going to look at the main two reasons: the level of maturity when a grape is harvested and the acidity level in a certain grape variety.

Level of Maturity When Grape Is Harvested

All varieties of grapes have a unique acidity profile. According to Lodi Wine Growers, there are two factors that help define that—pH level and titratable acidity. Specifically, pH levels don’t really affect the taste of the grape, so I will only focus on titratable acidity (TA). To put it simply, the level of TA is the measure of all acidity in a grape, and it’s what gives a grape a sour or bitter taste.

The TA level in a grape is highest when the grape begins to change colors. This is the point when the grape starts the ripening process, also known as veraison. This process is often encouraged by warm temperatures. Once the fruit begins to ripen, the acidity level in most grapes will naturally decrease as sugar levels increase.

If a grape is harvested at any point during veraison or right after, the grape will taste more sour than others. This is why sometimes you get a random sour grape in your bag of grapes from the grocery store.

Acidity Level in a Certain Grape Variety

Some grapes just taste more bitter than others—even at maturity! This is because certain varieties do not end up losing as much acid during the ripening process as others, so their acidity level is still high at maturity.

These unique, sour grapes are used to make different flavored wines and juices. In fact, winemakers take advantage of certain grapes’ acidity to give their wine a sharp taste. Let’s go over six of them!

Red and green grapes on a grape vine.

6 Varieties of Sour Grapes

1. Barbera

The Barbera grape is a red wine grape that originated in Italy as early as the 13th century, but it’s also present in Australia, Argentina, and the United States. It’s one of the most popular grapes to grow in Italy because of its prized acidity level. This grape alone covers over 50,000 acres in Italy!

The Barbera grape is dark red in color. It’s used to make a tart, full-bodied red wine that pairs well with dark meat and root vegetables.

2. Colombard

Colombard is an oblong white wine grape that originated in France as the offspring of the Chenin Blanc grape and the Gouais Blanc grape. It has recently spread to other vineyards in California and South Africa. Colombard has a high acidity level, and it’s made into a white wine that pairs well with trout, sushi, or salad.

3. Riesling

This is of the more familiar varieties of sour grapes. Riesling is a white wine grape that originated in the Rhine region and was discovered in Germany around the 15th century. It’s one of the most popular grapes used for winemaking.

Its acidity is noticeable in taste and smell, and in turn makes delicious, unique wine that pairs well with almost anything. You wouldn’t want to snack on this grape though, as it’s heavily seeded and surrounded with thin flesh.

Riesling wine and sour grapes on a table with a green background.

4. Sémillon

Sémillon is a white wine grape that is originally from Bordeaux, France. It has thin skin and ripens earlier than other grapes. Unique to other sour grapes, this grape’s acidity level is dependent on where it is grown and how long it has aged.

In France and the United States, it can tend to have low acidity and is used as a dessert wine. When grown in Australia and other areas, Sémillon tends to have high acidity because of when it is picked and is therefore used as a lighter wine.

5. Albariño

Albariño is a white wine grape that originated in Spain. It is also grown in parts of Portugal. This small grape has thick skin and will ripen into a greenish-golden hue. The high acidity level in this grape is apparent when made into a white wine. It pairs well with lighter meat like fish and oysters and herb-based sides.

6. Chenin Blanc

Chenin Blanc is a French white wine grape, and it is the parent of the Colombard grape that I mentioned above. Chenin Blanc has expanded to regions of South Africa as well as California, where it is primarily used as a dry white wine with high acidity.

The Chenin Blanc grape buds early and ripens in the middle of the season. It is said that the type of soil that the grape is grown in affects the taste. While heavy clay soils produce a heavier dessert wine taste, sandy soils produce a lighter wine.

How to Use Sour Grapes

Most of us aren’t winemakers (kudos if you are!), so how else can you use sour grapes? If you don’t enjoy the tart flavor of eating sour grapes outright, you can doctor the taste with different recipes.

A woman tasting sour grapes and making a face.

The easiest method is to find a recipe that adds sugar to balance out the acidity of the grape. Like in this recipe for Snow Grapes, you mix the grapes with sugar, cream cheese, sour cream, and vanilla extract to make a refrigerated fruit salad.

If you are a fan of sour grapes, try this recipe for Sour Patch Grapes as a dupe for Sour Patch Kids. You simply mix your grapes with lemon and several different kinds of Jell-O.

Verjus

If you have many sour, unripe grapes laying around, making a homemade verjus is a great idea! Verjus is a vinegar-like juice that is made from pressing unripe grapes. It can be used to make salad dressing or to make a sauce served with pork or other dark meats.

You can follow this recipe to create the verjus, then you can use your juice to make all kinds of delicious sauces and dressings!

Frequently Asked Questions

1. Can I grow any varieties of sour grapes in the US?

Yes, there are several varieties of sour grapes that can be grown in the United States. The Riesling grape, for example, can be grown in the northern regions of the country like New York and along the Central Coast of California.

2. Is it okay to eat unripe grapes?

Yes, juice from unripe grapes is fine to consume. In fact, unripe grape juice contains many helpful antioxidants for your body, and it can also help lower blood pressure.

Grapes hanging from a vine.

Now You Know All About Sour Grapes!

The next time you come across a sour grape, you can put it to use instead of throwing it out. From making verjus and delicious wine to creating fun desserts, sour grapes can be an interesting addition to your diet!

If you’re interested in more grape content, keep reading to learn about other tasty grape varieties!