The Easiest Homemade Low FODMAP Tomato Sauce

I love the crockpot! If there is an occasion to use it, I will find it. Dealing with my abundance of homegrown tomatoes was one of those occasions. Cooking up a pot of a delicious sauce is also a big money saver for us! There is only one brand of jarred sauce that I have found suitable for fructose malabsorption and that is Rao’s Sensitive Formula – and we like this sauce very much! It is made with no onion, garlic or added sugar, it has a smooth texture and both kids really like it. But! It is quite expensive. I’ll find it on sale (rarely happens) and stock up during the winter months. (Update: since this recipe was posted, we’ve found more tomato sauce brands we like and have listed them HERE.)

This recipe was snap. I threw all the ingredients in the crockpot, set it on high, and let it go for the day.

How to make a Low FODMAP tomato sauce from scratch.

I used fresh herbs gathered from our garden; 4-5 sprigs of oregano and about 30 leaves of basil. Twenty five tomatoes of varying sizes equalling about 20 cups were washed. The larger tomatoes were cut up into smaller pieces. No need to peel or seed them; I use the whole fruit. One lonely red pepper was chopped up as well. Feel free to add more or less herbs. If you don’t have fresh, dried will work as well, but you will have to alter your measurements and taste as you go.

I added about 1-2 tablespoons of garlic infused oil to the bottom of the crock pot to get the aroma going. Once all of the herbs and veggies were tucked into the crockpot I finished up with a tablespoon of salt and a few grinds of pepper. Then I set it on high and placed the lid on. After two hours, once the juices were boiling, I opened the lid a bit to allow the steam to evaporate – that way the sauce thickened up a bit. I cooked it on high for another 6 hours. I really like a thick and rich sauce, one that has cooked for hours. I’m sure it could have been used a little sooner, but I like the richness that is developed with an all day cooking.

fresh tomatoes in crockpot
emersion blender smoothing out the marinara

Next, I used an immersion blender to puree the sauce. You can certainly use a regular blender and ladle it in batches. I love my “boat motor” blender – I’ve had it for 15 years and it still works like a champ. I did let the sauce cool for several hours prior to blending it. If you do this while the sauce is hot – be careful!

This low FODMAP tomato sauce was blended until silky smooth. But you could leave it chunkier if that’s your preference. Since we used the whole tomato, I think this sauce is better smooth to blend in the peels, seeds and herbs. Now it is ready to use on your favorite pasta or portioned out for the freezer. We are certainly going to welcome the taste of fresh grown tomatoes come this winter. This batch yielded 5 quart containers. Typically we are safe with about a 1/4 cup serving.

portioned in quart freezer containers
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The Easiest Homemade Low FODMAP Tomato Sauce

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  • Yield: 5 Quarts 1x



2 Tb garlic infused oil

1820 cups fresh tomatoes (approx. 2325 depending on sizes)

45 springs fresh oregano (1 tsp dried)

30 leaves fresh basil

Salt and pepper to taste


Wash all tomatoes and fresh herbs.

Large tomatoes should be cut in large chunks.

Give herbs a rough chop.

Drizzle olive oil in a 6 Qt. slow cooker.

Add tomatoes and herbs.

Add a good sprinkling of salt and few grinds of pepper.

Place lid on cooker and cook on high for 2-3 hours. Once juices start to bubble, open the lid a bit to allow the steam to escape and the sauce can thicken. Cook for another 6 hours.

Allow sauce to cool an hour or so

Use an immersion blender to blend the sauce until smooth. Taste and adjust any seasonings as desired.

  • Author: Karina K.
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    • Hi! I use the Monash University FODMAP Diet app and according to them tomatoes are low in fructose and fructans, per serving. Now, with that said, everyone has different tolerances. This recipe works for us, but I caution everyone because we all have different triggers and sensitivities.

    • I believe it could be safely kept in the refrigerator for up to a week. But if you’re into canning, you could probably make a bulk batch of sauce and can it to keep it for longer.

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