Are Tomatoes Acidic or Alkaline?

Tomatoes are very popular in every kitchen and it is one of the most consumed fruits. This is mostly for their nutritional richness that helps in healthy skin, eyes and heart. Tomatoes are also popular because of their flavor and their availability in different forms, like soups, sauces, juice and purees. Despite of their popularity, many people don’t know: are tomatoes acidic or alkaline?

tomatoes are acidic

Fresh tomatoes have different pH from the cooked or canned tomatoes.

Fresh tomatoes’ pH is in the range of 4.3 – 4.9, which means that tomatoes are acidic. The canned tomatoes’ pH is in the range of 3.5 – 4.7, which makes them more acidic. The reason why they are more acidic when are canned is because of the preservation agent. Purees and tomato juices have a pH range of 4.1 – 4.6.

Acidity Level in Tomatoes

The acidity level in tomatoes can be associated with different factors such as the variety, ripeness, watering and amount of sunlight they get.

Tomato Variety

The acidity of a tomato can depend on its variety. Some varieties are more acidic than others.

Many heirloom varieties are lower in acid than “modern” tomato varieties (hybrid varieties).

Many varieties are higher in sugar; therefore, they have a sweet tomato flavor, which masks the acid flavor. The paste tomatoes are actually lower in acid than standard tomatoes.

The more balanced the acid and sugar is, the better the taste of the tomato. But we are all different and have different tastes. Some of us like sweet tomatoes and some of us will prefer the sour taste of tomatoes.

So, here are some examples of varieties depending on their flavor.

Sweet (High Sugar) tomato varieties:

Sour (High Acid) tomato varieties:


  • Black Krim – indeterminate
  • Purple Cherokee – indeterminate

Amount of Sunlight

The amount of sunlight that a tomato gets will make a difference as well in terms of acidity. The tomatoes’ ripening depends very much on the amount of sunlight.

So, tomatoes that grow in full sunshine, tend to be more acidic, whereas those tomatoes which are grown in shade or reduced daylight hours, will become less acidic.

Excessive sunlight can lead to uneven ripening. The top of the tomato will stay green or yellow, while the rest of it will become soft and ripen.

Ripeness of Fruit

The acidity level in tomatoes is associated with their degree of ripeness as well.

The more ripen the tomato is, the lower the acidity. The sourer the tomato’s flavor is, the highest the acidity.

But what exactly makes a tomato acidic? Tomatoes contain folic acid, citric acid, ascorbic acid and malic acid.

When the tomato is still unripe, the malic acid is the main component of all the above acids. As the tomato starts to mature and changing its color, the citric acid becomes the dominant acid.

So, if you want to avoid tomatoes that are too acidic, I would suggest harvesting only the ripest tomatoes.

For some tomato varieties is hard to tell whether they are ripe or not just by looking at them. Green Zebra will never turn yellow or red, it will stay green but will have yellow stripes when ripe.

Sometimes, it is easier to touch the tomatoes and stroke them gently to check whether they are soft or hard. If the tomato is soft enough, you can harvest it because that means it ripened.

The ripening of the tomatoes is determined by the temperature of its environment. So, the extreme temperatures (too hot or too cold) can lead to flavorless or bitter tomatoes, instead of sour, sweet or balanced.


As I stated in my other articles, watering is very important for your tomatoes.

Watering can influence even the taste of the tomato fruits. Lack of water leads to more acidic tomatoes and nutrient deficiencies as well.

Too much water will result in less acidic tomato fruits.

Watering affects the concentration of acid and sugar in your tomato fruits; therefore, their flavor will be affected. For example, when you take a spoon of sugar and dilute it in a cup of water will result in a sweeter taste than when you dilute the same amount of sugar in two cups of water.

How to Make Tomatoes Taste Sweet?

Just because a tomato fruit is homegrown, doesn’t mean it is sweeter. The actual flavor of a tomato depends on its chemistry and the environment in which it is grown.

As I said earlier, the tomato fruits’ flavor consists of the balance of acidity and sugar in the fruit. So, if the sugars are high, it results in sweet tomatoes, but if the acids are higher, that result in sour tomatoes. When both, sugar and acids, are low, the fruits will taste bland.

So, what can we make to harvest sweet tomatoes?

First of all, you should choose the suitable variety for your area. This is very important because the climate and the soil are crucial factors in terms of the taste of tomato fruits.

Some varieties might taste sweet in some areas but will do poorly in others. Different varieties prefer a different amount of rain or sunshine, different type of soil and different range of humidity and temperatures.

The taste of tomato fruits also depends on their size. Usually, cherry tomatoes are sweeter than the larger varieties such as beefsteak tomatoes.

If you want to have sweeter tomatoes, leaving them to ripen on the wine helps as well.

Adding fertilizers and organic matter to the soil makes also wonders. This helps in a natural healthy growth; therefore, the fruits will have a nice sweet flavor as well.

Wrap up

So, now we know that tomatoes are acidic fruits, but the level of acidity depends on many factors. Some of these factors, like the weather, cannot be controlled, but some of them can be controlled, like watering or deciding when to harvest the fruit.

If you pick the right variety for your taste and you are planting it in time, giving it enough time to develop and ripen, you won’t be disappointed.

If you have problems with heartburn try to avoid the more acidic varieties, and you can also combine them with alkaline foods like cucumber, avocado, spinach or kale.


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