If you’re looking for a fruit that will pucker your lips, you’ve come to the right place. Here is a list of the most sour fruits, according to Foodie Mike:
Sourness in fruit is typically associated with the presence of organic acids, such as citric, malic, and tartaric acids, among others. The amount of these acids in fruit can give us an idea of how sour a fruit might taste, although it’s important to note that other factors such as sugar content and flavor compounds can also influence our perception of sourness.
In a laboratory, you can measure the acidity (which often correlates with sourness) using a process called titration. This process involves adding a base solution to the fruit juice until it neutralizes the acid. The volume of base used gives a measure of the total acidity.
In simpler terms, a titration test measures how much of a certain substance (in this case, a base) is needed to neutralize the acid in the fruit. This can give us a sense of how much acid is present in the fruit, which can help us estimate its sourness.
However, this test doesn’t tell us about the balance of sourness with sweetness or other flavors in the fruit. Different fruits have different amounts of sugars and other flavor compounds that can make a fruit taste less sour even if it has a high amount of acid.
Another way to measure sourness, though less precise, is by measuring the pH level of the fruit juice. The pH scale runs from 0 (very acidic, or sour) to 14 (very basic), with 7 being neutral. The lower the pH, the more acidic (and thus potentially more sour) the fruit is. This can be done using a pH meter or pH indicator strips.
It’s important to note that these methods measure the acid content, but sourness is ultimately a sensory perception and can vary between individuals. For a comprehensive understanding of a fruit’s sourness, sensory evaluations, often in the form of taste tests conducted by panels, are usually employed alongside these scientific measurements. This way, the physical measurements can be correlated with actual human sensory experiences to better understand the sourness of a fruit.
Lemons

Bright yellow with a tough outer skin, lemons have a strong sour flavor due to their high citric acid content, around 5-6% of the fruit juice. They’re rich in Vitamin C, which is beneficial for immune function. One lemon contains about 20 calories. Lemons are often used in cooking and baking, as a garnish, and in beverages like lemonade or hot water with lemon.
Limes

Smaller and usually greener than lemons, limes also have a high citric acid content. They are known for their vitamin C content and potential antioxidant properties. A medium-sized lime has approximately 20 calories. Limes are commonly used in cooking and beverages, especially in Mexican and Thai cuisine, and they are essential for a number of cocktails like mojitos and margaritas.
Cranberries

These small, dark red berries are known for their tart taste. Their acidity levels can range around pH 2.3 to 2.5. Cranberries are rich in antioxidants and are often used to prevent urinary tract infections. A cup of cranberries contains about 50 calories. They’re typically consumed as juice, in baked goods, or as dried fruit.
Blackcurrants

These are small, dark purple berries with a tart flavor. Their pH levels range from 2.8 to 3.2. They are high in vitamin C and antioxidants. A cup of blackcurrants contains approximately 70 calories. They’re used in desserts, wines, and liqueurs, as well as to make jams and jellies.
Gooseberries

Gooseberries can range in color from green to red to black. They have a tart flavor and their pH levels range from 2.8 to 3.1. They are high in vitamin C and fiber. A cup of raw gooseberries contains about 66 calories. They’re often used in desserts and can be made into jams, jellies, and wines.
Sour cherries

Also known as tart cherries, they are smaller and more brightly colored than sweet cherries. They are acidic, with pH values from 3.2 to 3.7. They’re known for their high antioxidant content, especially anthocyanins, which can have anti-inflammatory effects. A cup of sour cherries contains around 50 calories. They’re often used in baking, as in cherry pies, and in beverages.
Green Apples (Granny Smith):

These are bright green apples with a strong tart flavor. Their pH levels range from 3.1 to 3.3. They’re high in fiber and vitamin C. A medium-sized Granny Smith apple has about 80 calories. They’re eaten fresh, used in baking, and make a great addition to salads.
Tamarinds

These tropical fruits have a hard, brown shell enclosing a sticky, sweet-and-sour pulp. The pH of tamarind is around 3.5. They’re high in fiber and contain various antioxidants. One cup of tamarind pulp contains approximately 287 calories. Tamarind is often used in Asian and Latin American cooking, especially in curries, soups, and chutneys.
Kumquats

These are small, oval citrus fruits that are eaten whole, skin and all. The flesh is sweet, while the skin is sour. Kumquats have a pH of about 3.6. They’re high in fiber, vitamin C, and other plant compounds beneficial for health. A serving of 5 kumquats has around 70 calories. They can be eaten fresh, used in salads, or made into marmalades and jellies.
Ume (Japanese apricot or plum)

Ume fruits are small and round, turning from green to yellow as they ripen. They have a sour flavor and a pH of approximately 2.5. They’re often fermented and salted to make umeboshi, which are believed to aid in digestion and combat fatigue. One ume fruit contains about 10 calories. Besides umeboshi, they are also used to make ume vinegar and umeshu, a sweet plum wine.
These are just a few of the most sour fruits in the world. If you’re looking for a fruit that will wake up your taste buds, be sure to try one of these sour fruits.