Do Tomatoes Get Sweeter When Cooked? (How To Sweeten)

Everyone loves a good Italian tomato sauce, rich with flavor, fresh with herbs, and sweet with caramelization. It often seems that a quickly cooked tomato sauce can be slightly bitter, but one simmered for a long time gets sweeter. I did some research to find out if this was true and this is what I found.

Tomatoes get sweeter when cooked because they contain natural sugars which release, caramelize and intensify when cooked. You can sweeten tomato sauce by simmering your canned or fresh tomatoes for longer or use a shortcut like adding sugar, diced carrots, or honey. Reduce the acidity with baking soda.

Sometimes we have time to cook for hours, but mid-week, the pasta sauce needs to be done in 20 minutes. If you don’t have gorgeous home-grown tomatoes or quality canned tomatoes, your sauce may become acidic, bitter, or watery.

What can you do to sweeten tomatoes if you don’t have time to simmer them for hours? Let’s look at the secrets of making a sweet tomato sauce every time.

Why Do Tomatoes Get Sweeter When Cooked?

Tomatoes are a fruit, not a vegetable, which explains why they are inherently sweet. As they ripen, tomatoes develop natural sugars called glucose and fructose, making the tomatoes flavorful and delicious. Sunlight increases the development of sugars, which is why tomatoes from sunny regions are sweeter and redder.

Cooking tomatoes helps to release the natural sugars as the cell walls expand and burst when heated. As the cooking process continues, the sugar caramelizes, becoming rich and extra sweet.

Tomato dishes also taste sweeter after simmering because the tomatoes release water with the sugar which cooks off or evaporates over time. This process makes the sweetness more intense, as less liquid remains to dilute the sugars – the sweet flavor is concentrated.

Many tomato species have been bred to be bright red, large, and have an extended shelf life. Unfortunately, these characteristics come with a reduced sweetness, so many store-bought tomatoes look good but don’t have a great deal of natural sweetness.

That is why for most people, using a quality canned tomato is best for sauces. They are usually plum tomatoes that are ripened on the vine to give maximum flavor, rather than picked early for the store. They are canned straight away to preserve them.

How Long To Cook Tomatoes

Although tomatoes do get sweeter as they cook, you can’t rely on cooking them for a short time and expecting the same level of sweetness as a long, slow simmer produces.

To develop that mellow sweetness for the best tomato sauce, you need to cook tomatoes for an hour or two. Unfortunately, you just can’t rush it and get the best results. Either slow cook a tomato sauce on the stove or roast tomatoes in olive oil, salt and pepper to concentrate their flavor. 

The shortest time you can cook tomatoes and expect to lose the raw tomato taste and develop some flavor is 15 to 20 minutes. If you are in a rush, cook your tomatoes in a skillet rather than a deep pot to expose the tomatoes to more heat, and the flavors can blend more quickly.

The Best Tomatoes For A Sweet Tomato Sauce

If you struggle to make a good tomato sauce, you might be using the wrong kind of tomatoes. Buying the best quality canned or fresh tomatoes you can afford makes a much better sauce.

  • Canned Italian plum tomatoes – the best option for most people who can’t get good-quality fresh tomatoes. Use whole plum tomatoes as the whole ones are better quality than the diced or crushed leftovers.
  • Source good fresh tomatoes – use the ripest, locally grown tomatoes you can buy – go to a farmer’s market if you can. Heirloom tomatoes are much sweeter than many stores’ handsome but flavorless specimens. San Marzano variety makes great sauces.
  • Remove skins and seeds – Tomato seeds and skins are often bitter, especially in a long-simmered sauce. Blanch in hot water to remove skins and cut in half to scoop out seeds. Or use a food mill for canned tomatoes.
  • Try roasting tomatoes first – Use a combination of fresh, roast, charred, or sun-dried tomatoes to increase the concentrated sweet tomato flavor. It’s easy to roast a batch of tomatoes, and they make the sauce taste fantastic.

To know what tomato varieties to use when, see my guide on what tomatoes are best for different recipes.

How To Sweeten Tomato Sauce With Sugar

If you taste your sauce at the end of cooking and find it still sour, add a pinch of sugar to sweeten it. Cook the sauce for two minutes more and taste again. Add another pinch if needed, until it tastes balanced – you don’t want it to taste sugary.

Sometimes, no matter how long you cook and coax tomatoes, they just don’t get sweet enough. If you’ve used unripe, end-of-season, or poor-quality canned tomatoes, they will remain stubbornly sour and tart. The answer? An Italian cookery secret – a little sugar.

Adding a little sugar can balance the tartness and acidity of tomatoes and is perfectly acceptable. However, sugar won’t transform the flavor of a sauce made from unripe tomatoes into that of a sauce made from ripe tomatoes. 

Take care not to slip in too much sugar or risk a sweet sugary sauce – you want to add just enough so it’s not bitter or sour. Most commercial pasta sauces and tomato sauces contain lots of sugar, which is why we’re used to sweeter tomato sauces.

How To Sweeten Tomato Sauce Without Sugar

Adding sugar to tomato sauce is a quick fix, but there are many other ways to sweeten tomato sauce without adding refined sugar.

  • Carrots – Including sweet vegetables in the tomato sauce is the Italian trick. Frying diced carrots (or red peppers) before adding tomatoes releases their mellow sweetness for a natural tasting sauce.
  • Honey – Add a teaspoon or two of honey or maple syrup, which has the same effect as sugar.
  • Butter – A cube of butter helps to mellow the tomatoes’ acidity and enriches the sauce.
  • Salt – Salt highlights the tomatoes’ sweet flavor in the same ways it’s added to chocolate or salted caramel. Salt is a flavor enhancer, intensifying other foods’ flavors, so we add it to most dishes.
  • Sausage – Toss in some browned sweet Italian sausage with its fragrant fennel to flavor the sauce.
  • Baking soda – add a pinch or two of baking soda to neutralize acidity. The baking soda will make the sauce froth up a bit like in science class. It’s safe to use but be wary of the slight taste it adds.

Do Carrots Sweeten Tomato Sauce?

Sweet vegetables like carrots can sweeten your tomato sauce. Carrots, onions, and celery all contain natural sugars released during cooking, especially caramelization. Starting a tomato sauce by sauteeing these base ingredients will create a sweeter sauce.

If you’re concerned about the texture that pieces of carrot will give your tomato sauce, finely dice or grate the carrots. You can also whizz the carrots in a food processor.

Alternatively, just add a whole carrot to the sauce. This helps sweeten the sauce as it releases its sweet flavors but also absorbs the bitterness. Discard the whole carrot at the end.


Hopefully, you now know if tomatoes get sweeter when cooked. The secret to a balanced tomato sauce with rich, complex flavors is to use naturally sweet tomatoes and simmer them for an hour or more.

Add sugar, honey, carrots, or sweet sausage if your sauce still lacks sweetness. Try adding baking soda to counteract the acidity of the tomatoes and salt to intensify the sweetness.

Have any questions? Ask me in the comment section below and I’ll get back to you.

Tom Hambly

Tom Hambly is the founder of Boss The Kitchen. With a background in cooking and building websites, he enjoys running this site to help other cooks improve. About Tom Hambly.

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