Sour is one of the five basic tastes, along with bitter, sweet, salty, and umami (1).

Sourness is the result of high amounts of acid in foods. Citrus fruits, for example, have high amounts of citric acid, giving them their characteristic lip-puckering flavor (1, 2).

However, unlike the other five tastes, researchers still don’t completely understand the mechanism behind how sour taste receptors work or why some acids result in a stronger sour flavor than others (1, 2, 3, 4).

As is the case with bitterness, the detection of sour is thought to be important for survival. It can help identify foods that could be dangerous to consume, as rotten or spoiled foods often have a sour flavor due to the growth of bacteria (5, 6).

Yet, this doesn’t mean that sour foods are always unsafe to eat.

In fact, many sour foods are quite nutritious and rich in plant compounds called antioxidants, which help protect your cells from damage (7, 8).

Here are 13 lip-puckering sour foods that can be healthy additions to your diet.

Citrus fruits are known for their vibrant colors and distinctive flavors.

While they all have a hint of sourness, the balance of sweet and sour varies greatly between different types.

Some of the more sour-tasting citrus fruits include:

  • Calamansi: a small green citrus fruit that tastes similar to a sour orange or sweeter lime
  • Grapefruit: a large tropical citrus fruit with a sour, slightly bitter flavor
  • Kumquats: small orange fruits with a sour-sweet flavor and edible peel
  • Lemons: yellow citrus fruits that have a strong sour flavor
  • Limes: small green citrus fruits that taste more sour than sweet
  • Oranges: a type of citrus with many varieties that range in size and flavor, with some being sweeter than others
  • Pomelo: a very large citrus fruit that’s yellow when fully ripe and tastes similar to grapefruit but less bitter

Citrus fruits contain a high concentration of citric acid — a naturally occurring compound found in a variety of fruits that imparts a tart, sour flavor (9).

In addition to being the best natural sources of citric acid, these fruits are known for being high in vitamin C, which is essential for a strong immune system and skin health (9, 10, 11).

They’re also a good source of many other nutrients, including fiber, B vitamins, potassium, phosphorus, magnesium, and copper, as well as plant compounds with antioxidant and anti-inflammatory properties (12).

Tart citrus juices like lemon and lime juice add a bright flavor to marinades and salad dressings, while slightly sweeter fruits, including oranges and pomelos, can be peeled and eaten on their own as a snack.

Tamarind is a tropical fruit that’s native to Africa and comes from the tamarind tree (Tamarindus indica) (13).

When the fruit is still young and not yet ripened, it has a green pulp that’s very sour.

As the fruit ripens, the pulp softens into a paste-like consistency and becomes more sweet-sour tasting (13).

Similarly to citrus fruits, tamarind contains citric acid. However, the majority of its tart flavor is due to its high concentration of tartaric acid (13, 14).

Tartaric acid is a naturally occurring compound that has been shown to have antioxidant properties and may help prevent the formation of kidney stones (15).

In addition to being found naturally in fruits like tamarind and grapes, tartaric acid is used as a food additive to provide a tart flavor (15).

Nutritionally, tamarind is a good source of several essential nutrients, including B vitamins, magnesium, and potassium (14).

It’s also quite versatile, as the pulp can add a tart-sweet flavor to marinades, chutneys, beverages, and desserts.

Rhubarb is a unique vegetable, as it has a strong tart flavor that’s due to its high concentrations of malic and oxalic acids (16, 17).

In addition to being quite sour, rhubarb stalks are low in sugar. As a result, they have an unpleasant tartness and are rarely eaten raw.

Instead, they’re normally cooked and used as an ingredient in sauces, jams, or beverages. They’re also frequently combined with sugar and other fruits to make pies, crisps, and crumbles.

With the exception of vitamin K, rhubarb is not particularly high in many vitamins or minerals. However, it’s a rich source of plant compounds with antioxidant properties, including anthocyanins (16, 18).

Anthocyanins are potent antioxidants that are responsible for giving rhubarb stalks their vibrant red color. They have also been shown to protect against several chronic conditions, including heart disease, cancer, obesity, and type 2 diabetes (19, 20).

Tart cherries (Prunus cerasus L.) are small stone fruits with a bright red color and sour flavor (21).

Compared with sweet cherries (Prunus avium L.), tart cherries are lower in sugar while containing high amounts of malic acid, which is responsible for their sour flavor (21).

Tart cherries are also rich in antioxidants, particularly polyphenols. These plant compounds have been associated with reduced inflammation, as well as improved brain and heart health (22, 23).

Additionally, drinking tart cherry juice may help reduce exercise-induced muscle injury and soreness in athletes and active adults (24, 25).

Pitted tart cherries can be easily added to a healthy diet by adding them to salads, placing them on top of yogurt or oatmeal, cooking them down into a sauce or marinade, or blending them into a smoothie.

Gooseberries are small, rounded fruits that come in a variety of colors and can range in flavor from sweet to quite sour (26).

They contain several organic acids, including citric and malic acids, which are responsible for their tart flavor (27).

Research suggests that these organic acids may also benefit heart health and have antioxidant and antimicrobial properties (27, 28).

Another benefit of gooseberries is that they’re an excellent source of vitamin C. Just 1 cup (150 grams) provides 46% of the Daily Value (DV) (29).

After being washed, gooseberries can be eaten on their own as a snack or added on top of oatmeal, yogurt, or salads. Just remember that they can be quite tart. For a sweeter flavor, look for gooseberries that are riper.

Raw cranberries have a sharp, tart flavor due to their low sugar content and high concentration of organic acids, including citric and malic acids (30).

In addition to providing a sour flavor, their unique combination of organic acids is thought to be part of the reason why cranberry juice and capsules may help prevent and treat urinary tract infections (UTIs) (30, 31).

While cranberry juice can be high in added sugars and low in fiber, whole cranberries are a nutrient-rich addition to your diet, as they provide important nutrients like manganese, fiber, and vitamins C and E (32).

Cranberries are also one of the richest sources of quercetin — a plant compound that has been linked to antioxidant, anti-inflammatory, anticancer, antifungal, and antibacterial properties (33, 34, 35).

Fresh cranberries can add a tart flavor to mixed green and grain salads, sauces, and chutneys, while dried cranberries can be mixed into homemade granola bars or trail mix.

Vinegar is a liquid made by fermenting a carbohydrate source, such as a grain or fruit, to turn the sugars into alcohol. To help with this process, bacteria are often added to further break down the sugars (36).

One of the byproducts of this fermentation process is acetic acid — the main active component in vinegar and primary reason why vinegar tastes so sour (36, 37).

In animal studies and a few small human trials, acetic acid has been shown to aid weight loss, fat loss, and appetite control, as well as help manage blood sugar levels in those with type 2 diabetes (38, 39, 40).

However, more research is needed to determine an effective and safe dose to provide these benefits in humans.

There are many types of vinegars, each with their own flavor depending on the carb source from which they were fermented. Common types include rice, apple cider, red wine, and balsamic vinegars.

Vinegars are typically used as ingredients in sauces, marinades, and dressings. More flavorful vinegars like balsamic may also be drizzled over dishes like pizza, pasta, and sandwiches.

Kimchi is a traditional Korean side dish made from fermented vegetables and spices.

Commonly made with cabbage, the vegetable and spice mixture is first pickled in a salty brine. It’s then fermented with Bacillus bacteria, which further break down the natural sugars in the vegetables, producing lactic acid (41).

It’s this lactic acid that gives kimchi its signature sour smell and flavor.

Used as a side dish or condiment, kimchi is a good source of probiotics. As a result, regular consumption of kimchi has been linked to benefits for heart and gut health (42, 43).

Thought to have originated in China, sauerkraut is a type of fermented cabbage that’s commonly found in German cuisine.

Similarly to kimchi, sauerkraut is made by fermenting shredded cabbage with Bacillus bacteria, producing lactic acid. It’s this lactic acid that gives sauerkraut its distinctive sour flavor (44).

Due to fermentation, sauerkraut is often rich in beneficial bacteria known as probiotics, which are important for digestive health (45, 46).

It’s also rich in fiber and several important vitamins and minerals, such as manganese and vitamins C and K (47).

While it can be a nutritious way to add flavor to sandwiches or meat dishes, keep in mind that sauerkraut can also be high in sodium.

Yogurt is a popular fermented dairy product that’s made by adding live bacteria to milk. As the bacteria break down the natural sugars in milk, lactic acid is created, giving yogurt a sour taste and smell (48).

However, to help make yogurt less tart, many products also contain added sugars and flavorings.

In addition to being a good source of probiotics, yogurt is rich in protein, calcium, and phosphorus — all of which are important for bone health (49, 50).

Additionally, regular yogurt intake has been suggested to aid weight loss in individuals with obesity (51, 52).

Plain yogurt can be topped with fruit for a healthy snack. It can also be used as a fat substitute in baking or replacement for mayonnaise or sour cream in salad dressings and dips.

Often described as a drinkable yogurt, kefir is a fermented beverage made by adding kefir grains to cow’s or goat’s milk (53).

As kefir grains can contain up to 61 strains of bacteria and yeasts, it’s considered to be a more diverse and powerful source of probiotics than yogurt (54).

As with other fermented foods, kefir has a tart flavor that’s largely due to the production of lactic acid during fermentation. Plus, similarly to yogurt, kefir products often have added sugars and flavorings to make them sweeter and less sour.

Interestingly, kefir may be well tolerated by individuals with an intolerance to lactose, a sugar in milk, as most of the lactose is turned into lactic acid during fermentation (55).

However, for a 100% lactose-free option, kefir can also be made with non-dairy liquids, such as coconut water or fruit juice.

Kombucha is a popular fermented tea drink that dates back to ancient times (56).

It’s made by combining black or green tea with sugar, yeast, and specific strains of bacteria. The mixture is then left to ferment for 1 week or longer (56).

The resulting beverage has a lip-puckering sourness that’s largely due to the formation of acetic acid, which is also found in vinegar (56).

While both black and green tea have been shown to be rich in antioxidants and may help reduce your risk of heart disease and certain types of cancer, research is currently lacking on whether drinking kombucha has the same protective effects (57, 58).

Japanese apricots (Prunus mume), also referred to as Japanese plums or Chinese plums, are small, rounded fruits that are typically dried or pickled before eating (59, 60).

Both dried and pickled Japanese apricots — known as umeboshi — are especially tart, as they have a high concentration of citric and malic acids (59).

As they’re rich in antioxidants and high in fiber, animal studies have suggested that Japanese apricots may have anticancer properties and be beneficial for digestive health. However, research in humans is lacking (61, 62, 63).

Dried and pickled Japanese apricots are often paired with rice to add a potent sour flavor. However, given that they can also be high in sodium, it’s best to use them in moderation.

Sour is one of the five basic tastes, and tasting sour indicates the presence of an acid in food, such as citric or lactic acid.

While sourness can be a warning sign of spoiled or rotten food, many sour foods are perfectly safe and healthy to eat.

Some lip-puckering foods that also have nutritional benefits include citrus fruits, tamarind, rhubarb, gooseberries, kimchi, yogurt, and kefir.

Try adding a few sour foods to your diet for a boost of flavor and health benefits.