I'm trying to make soups (e.g. tomato soups, with some veggies, chillies, etc) and would like to make its cost lowest possible.

One problem that I have to solve is choosing the right thickening agent in order to make the soup cheapest possible.

Flour seems a common choice, but there is also xanthan gum. Xanthan gum is more expensive per gram, but looking at the cost per gram is misleading as different amounts in grams are required to thicken a given volume. For example, only a few grams of xanthan gum are required to thicken a serving.

To be more specific, suppose that I have 500ml of hot water that I'd like to thicken, what's the cheapest way to thicken it with a soup-like consistency?

There are many more thickening agents than the two that I have mentioned so far, and this complicates the problem for me as I'm not experienced with thickening agents nor soups. Therefore, experts' opinions here would be really helpful, specially that this question seems not answered here, and my search attempts failed to find any website that answers it.

  • 15
    @caveman that makes no culinary sense. It's like choosing a carpet and building the house that goes with it :) But if you absolutely want to go that way, then the answer is trivial: Don't use any thickening. Soups don't need to be thickened, and if you make a recipe where you don't use any, the cost will be zero.
    – rumtscho
    Commented Feb 15, 2023 at 9:48
  • 8
    You can't build it backwards, because everything in the food affects the texture. If you were to first make the "perfect" texture from just a thickener and water, then the moment you add something else, that texture will be changed. The thickener is the last element that adjusts the texture without changing the rest.
    – rumtscho
    Commented Feb 15, 2023 at 10:40
  • 5
    And also, my comment about the trivial solution stands. If your criteria are just thickness and thickener cost, then you can simply choose to make a soup which has the desired thickness, then you don't need to add any thickener, and the cost of the thickener is again zero.
    – rumtscho
    Commented Feb 15, 2023 at 11:06
  • 6
    I've just never needed to, in 30 years of making them.
    – Tetsujin
    Commented Feb 15, 2023 at 13:20
  • 6
    @caveman no, they're more expensive as pure thickeners, but they're a good part of a cheap diet that happens to provide thickening to soup. In general, considering how to save money on one small aspect of cooking isn't the best idea. Taken to extremes you'd just have slightly thickened water with no flavour and next to no calories. That's not much use
    – Chris H
    Commented Feb 15, 2023 at 14:15

5 Answers 5


An absolutely definitive answer would be based on a formula that takes into account the thickening power per weight of different thickeners as well as the cost per weight of the thickening agent.

That's completely unnecessary however because I can tell you without a doubt that the cheapest thickener is wheat flour. I don't have to do any of that work because food companies have done that for me: they keep their prices competitive by getting the most effect out of the least price, and they use wheat flour and cornstarch for soup thickening almost exclusively. Xanthan gum may be used in some gluten free recipes, but it's rare. If it was cost effective they'd be using it everywhere.

Of the two most frequently used, cornstarch is double the thickening power of flour, but is far more expensive. The quick checks I did showed anywhere between 10-20 time the price of flour, so at least 5 times the cost for equivalent thickening power.

Cornstarch has distinct advantages over flour as a thickener: it doesn't need to be cooked before it's added and it adds a nice gloss, however purely on a cost basis you won't get cheaper than flour.

  • 2
    I suspect that in manufacturing quantities corn starch is more competitive in price than it is in the supermarket. I'm used to seeing it sold in smaller and more robust containers than wheat flour, as it's expected to be kept for a long time. As corn starch can be added late, you can use as much or as little as you want. Doing that by cooking and adding a roux is possible but takes more heat, and the energy cost will be worth considering
    – Chris H
    Commented Feb 15, 2023 at 10:18
  • 1
    Quick check with my local wholesaler: a kilo package of cornstarch is €2,50, all purpose flour about 90ct. In thickening power I'd think that cornstarch has more than twice the power so in pure cost that might be better for say, a commercial kitchen. But it may well be that when you order by the ton it swings the other way again.
    – Borgh
    Commented Feb 15, 2023 at 10:26
  • 1
    You are right in everything you say @ChrisH. I'm answering the narrow scope of the question.
    – GdD
    Commented Feb 15, 2023 at 10:32
  • 2
    @caveman the problem seems to be that you lack the understanding that thickening agents come in the context of a whole soup, so speaking of "just the thickening agent" without the rest of the soup makes little sense.
    – Esther
    Commented Feb 16, 2023 at 20:49
  • 2
    @Esther is making perfect sense. What is quite clear from the comments is that you actually don't understand the problem, so you're struggling with how people are explaining it to you. BTW, you cannot put either cornstarch or flour straight into boiling or near-boiling water, all you will get is lumps of solid which will never break down. if there is no roux process, then you have to add as a cold slurry to below boiling almost finished liquid, then stir briskly until it thickens. Both will lose consistency if over-heated, & cornstarch will gelatinise if allowed to cool.
    – Tetsujin
    Commented Feb 17, 2023 at 16:32

While you can't go in general cheaper than wheat flour, two of your example soups might even work without any thickener.

Rice, bread, potatoes and beans are great for natural thickeners. If you don't count them as extra since they are already in the soup, this would be the cheapest option since you don't add anything.

  • I have to count them as extra, as I'll be adding more of them in order to cause a thickening of the same volume. If I add a cheap thickening agent, I can add lesser of those ingredients, and thicken it separately by an agent.
    – caveman
    Commented Feb 15, 2023 at 22:01
  • @caveman and what will you do about the loss of flavor that comes from using less of an ingredient? Most of the time, if you use enough ingredient to get decent flavor, you have sufficient thickening. Unless you're using soup powder, in which case it probably comes with its own thickener.
    – Esther
    Commented Feb 16, 2023 at 3:50
  • @Esther - I will find whatever flavour enhancer that goes with thickener.
    – caveman
    Commented Feb 16, 2023 at 4:16
  • so you're making a soup powder, not a soup? that is important context. You want to make a "soup" out of water + flavors and thickener, and are looking for the cheapest method?
    – Esther
    Commented Feb 16, 2023 at 20:48

How's this for cheap: Save the water you boil your pasta in. Not much thickening power, but you could reduce it too.

  • Have you considered the cost of energy and the reduction process? I guess it would nonetheless help the flavour, but not sure how much thickening power it has.
    – caveman
    Commented Feb 15, 2023 at 21:59
  • 5
    Well - a lot of folks cook pasta in very little water, which reduces the amount of thickening needed. Commented Feb 16, 2023 at 6:03

Possibly the cheapest thickener is simply the soup itself. Remove a portion of your soup, liquids and solids together, and puree using a blender. Return the puree to the pot of soup and check the texture - if you want it thicker, just repeat with another portion of soup.

The ingredient cost is zero. The energy cost of running a blender for a minute or two should also be very small. However, the up-front cost of buying a blender (if you don't already own one) may be a barrier, even though the price per pot of soup over its lifetime will be tiny.


Essentially, you're describing an industrial question. Interesting. That said, why not take the solutions from the soup powder industry?

To that end, I would suggest a two part approach. Like using a coarse and then a fine sand paper to smooth a piece of wood.

Part 1 is the higher-volume part: Starch. Cornstarch or potato starch are probably the cheapest and most easily accessible. Note that it is best to dissolve the starch in some water before adding it to the soup. This just helps avoid lumping.

Part 2 is a low-volume, fine texture additive: Maltodextrin. This isn't as trivially easy to come by, but it should be possible. It's also not expensive at all, and you'll only need less than 1 Tbsp for a big pot of soup. Note that Maltodextrin has quite a high glycemic index, even higher than starch or sugar.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.