Thickening Tomato Sauce

tomato paste, yes it's not as fresh but it is a good way to thicken it

You may not like the answer but you need to cook it longer. When O do my sauce with fresh tomatoes it simmers for close to 12 hours. Usually I make it the day or so before I need it. That way I don't have to do all the cooking in one day. Helps the flavor too. If you're going to go through all the trouble of preparing the tomatoes for cooking why throw in paste.

Paste has it place. I use it but not with fresh tomatoes.

You can also cut your tomatoes the day before you need them, place them in a china cap, collander or chinoise and drain them into a bowl over night. This will also remove a good deal of moisture. :)

A number of issues here

Canned Tomatoes
Canned tomatoes can be surprisingly good or plain awful. It sounds like you're using whole tomatoes, a good start. But what are they packed in? As a generalization, puree is better than juice which is better than water. Read your ingredients to find out what you've got. This is probably one of your problems with runniness.

Also look at additives. There are usually two: Salt and Calcium Chloride. Salt offers some flavor and preservative effects. Calcium Chloride has a very salty flavor, is a firming agent as well. Purists avoid the calcium chloride. I have a sodium restricted diet so I actually use a brand with only tomatoes and calcium chloride which works well for me.

I do have to give props to Pomi brand tomatoes whose aseptic packages list but one ingredient: Tomatoes. I used Pomi exclusively when I lived in Germany and was very happy with the product. They're quite a bit more expensive here in Europe.

Muir Glen is a respected quality brand of canned tomatoes in the US and can be had at reasonable prices on sale, but is otherwise expensive in my book. I stock up at sales.

THICKNESS

Thickening may not be what you want to do really. It depends on what you want to do with it.

The more you cook a tomato sauce, the less tomato impact it tends to have. There are times this is what you want such as a bolognese with a more blended meaty flavor.

But for pizza or marinara, a fresher tomato taste is generally desirable.

Here are some ideas you may find useful.

Drain your tomatoes and reserve the liquid. Lightly crush the tomatoes and drain again adding that liquid to the reserved liquid.

Mill your tomatoes as normal. You could add in the amount of liquid you want for the sauce so you have the fresh taste of a less cooked sauce. Or you might try reducing the liquid and blending that into the solids. I'm not sure where the flavor profile would end up though.

Phil

When I simmer a sauce that I know will take a long time to thicken, I do it in the oven at about 250 degrees. Then I don't have to stir it as often to keep it from scorching.

I'm with old school on this one. Even my Marinara sauce gets a good 6 hours of simmer before I finish it. Slurry in tomato sauce is a travesty of justice. The other possible issue is that your sauce is not homogenous. If you have a lot of chunky solids and separate water, a couple of pulses with an immersion blender helps. Just don't kill it or you will have ketchup. Also, when I finish my sauce I mount it with a good bit of extra virgin olive oil. This helps to emulsify the sauce and give it body. It also gives Marinara sauce much needed fatty richness.

Hi French Foodie,

There is good advise here already.

Here are my observations:
Choose quality tomatoes.
as already stated, simmer, simmer then simmer longer.

Regular home cornstarch will not hold too long in an acidic environment like tomato sauce.

Add lemon juice, the added acid will help the natural pectin to firm up. (citric acid is better if you can find some).

If all else fails, add tomato paste.

Luc H.

When I make sauce using canned tomatoes, I prefer the juice to the puree. I drain the liquid, hand crush the tomatoes, and simmer in a skillet or saute pan to allow for more rapid evaporation. After the sauce has drained, I add back some liquid and add a little red wine. I can make a nice thick sauce in about 1/2 - 45 minutes.

shel