My Tomatoes Taste Bitter Or Sour – All You Need To Know

Tomato plant with a mix of ripe red, orange, and green fruits supported by a blue stake, possibly bitter or sour to taste.

For anyone that takes pride in growing their tomatoes, having your tomatoes taste bitter or taste sour can be quite disheartening.

In such unfortunate outcomes, it is wise to identify what would have gone wrong to avoid making the same mistakes. Additionally, even store-bought tomatoes can also taste off. The cheap tinned varieties are well-known for having an unpleasant “metallic” taste.

Consequently, it is ideal to have an arsenal of cooking solutions that can be used in most tomato-based dishes, to counter the taste of sour or bitter tomatoes.

What Causes Bitterness and Sourness in Tomatoes?

The flavor of tomatoes is often described as sweet, tangy, and mild.

Over 400 aromatic and volatile compounds determine the taste, but the most prominent components are sugar and acid. The main sugars in tomatoes are fructose and glucose, which give a sweet flavor. While the main acids are citric acid and malic acid, which give a tart flavor and promote salivation.

When the flavor components of tomatoes are unbalanced, the most common consequences are the development of bitterness or sourness in the fruits. These two tastes can be hard to distinguish and are commonly mistaken for each other.

However, they occur under different conditions. Sourness develops when foods have an acidic pH (between 0 to 7). In tomatoes, this typically occurs when they are picked too early. Bitterness, on the other hand, develops when the pH of foods is alkaline (between 7 to 14).

In tomatoes, it often develops in overripe fruits.

Tomato Type

Individual palate and tomato types can be considered to contribute the most to the taste of tomatoes. Most people prefer tomatoes with equally balanced sweetness and tartness, but several varieties are naturally quite acidic or bitter. Interestingly, in some bitter varieties, the taste is more due to the “mouth feel” of the tomato skin than the volatile compounds produced.

Environmental Factors

Environmental factors also contribute significantly to the development of flavors in tomatoes. Plants often produce sour or bitter-tasting fruits when they get inadequate sunlight or when pests and diseases attack them. Growing tomato plants in nutrient-poor soils or excessively watering fruits also affects their taste.

Additionally, wide tomato varieties have lost their sweetness over decades of intensive commercial farming.Tomatoes were originally sweet, multi-colored berries that were smaller than peas.

However, selective breeding favored higher yields, disease resistance, and firmness over taste. This has resulted in the alteration or loss of essential flavor genes, and wide varieties of tomatoes available today are less sweet, bland, sour, or bitter.

How To Avoid Growing Bitter or Sour Tomatoes

The flavor of homegrown tomatoes is primarily determined by their variety and the conditions under which they are grown. These factors lead to differences in the production of sugars, acids, and other complex flavors as plants mature.

Consequently, to avoid growing bitter or sour tomatoes, the plant type must be selected wisely, and the best gardening practices must be implemented, as listed below:

Tomato Variety:


Smaller-sized tomatoes, like cherry and grape tomatoes, tend to have higher sugar concentrations. They have not been exhaustively bred, so they retain unique and robust flavors and taste sweeter than fuller-sized tomatoes.


Different pigments in tomatoes produce different balances of sugars and acids. This holds for both hybrid and heirloom tomato varieties.

The most acidic types are red, green, purple, and black tomatoes. Red tomatoes, in particular, are characteristically very juicy and are known to have a “classic” tomato taste. Green, purple, and black tomatoes have more complex atypical flavors that tend to be enjoyed by some but disliked by others. Orange, yellow, and pink tomatoes have medium acidity, while white and bi-colored tomatoes have the least acidity and greatest sweetness among tomatoes.


Tomato plants with more leaves trap more sunlight, converting them into sugars and other flavor compounds. Heirloom varieties tend to produce more leaves than hybrids, and this, in part, explains why they make intense distinctive flavors.

However, no matter what type of tomatoes are planted, careful pruning can help to maintain leaf health and promote dense foliage.

Growth Conditions:

Sunlight And Temperature

To avoid growing sour tomatoes, select suitable varieties based on the climate you will grow them. Generally, tomato plants require a lot of sunlight and heat to grow well and produce flavorful fruits. At least 8 hours of sunlight a day is necessary, with a daytime temperature of at least 80oF and a nighttime temperature of at least 50oF.

However, some tomatoes are tolerant of cold and cloudy conditions and can be successfully grown in cooler regions.


To grow fruits with a well-balanced flavor, you must water your tomato plants consistently before they begin to yield fruits. Once fruits appear, you must only water them sparingly because drier and hotter conditions increase flavor production and concentration.

Spacing Tomatoes

Tomato plants must be well spaced to avoid crowding, which blocks sunlight from reaching the tomatoes well. Crowded vegetables often have stunted growth, reduced fruit production, and poor sugar production. Additionally, crowding promotes pest and disease spread.

Pest and Disease Control

Stink bugs, aphids, and other pests that feed on tomatoes can damage them and ruin the taste of the fruits. Diseases like late blight caused by fungal infections can also severely affect tomato taste, leading to bitterness.

Pests and diseases can be hard to control, but you can utilize some simple and non-toxic control measures to avoid plant damage. For instance, using a spray bottle with soapy water removes or kills insects from plants. You can also make an antifungal spray by mixing baking soda, vegetable oil paste, water, and castile soap.