Currently, my home ketchup recipe involves using around 2.2 pounds of canned tomatoes to make 3.4oz/100ml of ketchup.

A full can of tomatoes costs me around USD$4.50 here. This means that 3.4 oz, or 100ml of ketchup costs me approximately USD4.50 to make. This is quite expensive if you compare to a bottle of Heinz ketchup which costs onl USD$2.80 for a whopping 32 oz/1 litre bottle.

How can I 'stretch' my canned tomatoes so that I can make more ketchup out of it?

I have thought of adding corn syrup.

This is my full recipe: 2.2 pounds of canned tomatoes 350ml white distilled vinegar 1 tablespoon lemon juice 100ml of water 45g sugar Salt to taste

  1. Add water and blend the canned tomatoes using a hand blender or food processor.
  2. Run the mixture through a fine mesh sieve twice, until you get all the juice out.
  3. Add the juice and vinegar to a saucepan and simmer the mix until you reach your desired consistency. It normally takes me 2- 4 hours to reduce it fully.
  • Could you describe what you like better about your homemade ketchup recipe over Heinz Ketchup? Are you trying to save money, is the flavor important, or just sourcing of ingredients and control of sugar content? Or something else?
    – Wolfgang
    Commented Aug 3, 2017 at 19:56
  • I'm trying to taste a ketchup that uses less sugar but still manages to be great. Heinz is great, but I feel like it uses too much sugar and corn syrup.
    – user60513
    Commented Aug 4, 2017 at 0:54
  • I've added a bit to my answer about mixing with commercial ketchup. Do consider adding other ingredients to boost flavour and a personal touch.
    – Wolfgang
    Commented Aug 4, 2017 at 1:06
  • A kilo of tomatoes turns into .1 kilo of ketchup? That's gonna be some powerful ketchup. Bet it's delicious. Commented Aug 4, 2017 at 15:21

3 Answers 3


I guess comments are discouraged as answers, so I've moved this to an answer.

You could stretch it with Heinz (or other brand, French's maybe) ketchup. If its a taste thing, it would lower the quality but still be better than store bought. Since you're looking to lower sugar/corn syrup content, try reducing the sugar in your recipe to compensate for the extra sugar in the commercial products. You could even remove it entirely and adjust upward from there.

Alternatively you could try beef or chicken stock, heavily reduced, but this would cause significant changes to the taste and you may still need to adjust the water content and add a thickening agent. If you are making your own stock, pork bones can often be found for an exceptionally low price.

You could also try similar vegetables that are cheaper than tomatoes. Throwing in a few onions could stretch it a bit farther. Hot peppers could add some spice and make it go a bit further as well.

That also sounds very expensive for canned tomatoes. I've gotten them on sale for 28 oz for $1-$2 CAD in the past (this depends on your location, of course). Consider shopping around if you haven't, or switch to a cheaper brand (you can doba taste comparison to see if the quality is similar). Amazon currently has canned tomatoes for $0.13 USD/oz, so consider an online source as well. Otherwise you can probably can your own tomatoes when they are in season for cheaper.

Not directly part of the answer, but I also found this article from the Washington Post that might provide some insight:

Americans didn't always have a singular idea of what ketchup should taste like. Indeed, the first ketchups weren't made from tomatoes at all. According to "Pure Ketchup," Andrew F. Smith's definitive history of the condiment, the first known English-language recipe was published in the 1727 edition of E. Smith's "Compleat Housewife" and called for anchovies, shallots, white wine vinegar and spices such as mace, ginger, cloves and lemon peel, making it closer to an Asian fish sauce. By the early 19th century, cookbooks offered a range of recipes for ketchup made with walnuts, mushrooms, lemons, cucumbers, oysters and, of course, tomatoes.


Heinz's recipe is a trade secret. But some of the brand's earliest recipes are not. Its first blend included cloves, cayenne pepper, mace, cinnamon and allspice. The second had black and white pepper, ginger, mustard seed, horseradish, celery seed and brown sugar. Vinegar and salt were added to taste.

You could consider adding more ingredients to boost the flavor, and then water and a some amount thickener to stretch the amount of final product.

  • Indeed! Comments should never be used to answer the question. This is a network-wide prohibition but some sites are more willing to overlook it. In general, if you have an answer, we would like you to answer the question so that it can be voted on. Comments can only be upvoted, so there's no way to know how good of a suggestion they are.
    – Catija
    Commented Aug 3, 2017 at 19:21
  • Thank you for your answer, Wolfgang. Do you have any thickeners to recommend?
    – user60513
    Commented Aug 4, 2017 at 5:31
  • You can add some corn starch toward the end of the cooking, before your sauce is fully reduced. A question here discusses how to use corn starch for thckening: cooking.stackexchange.com/questions/9220/…
    – Wolfgang
    Commented Aug 4, 2017 at 12:01

I think your answer is found by responding to the question: "Why do I make my own ketchup?" Heinz ketchup is delicious. It is also produced in mass quantities. You'll never compete on cost because of economies of scale. If you are purchasing ingredients, homemade ketchup is just going to cost more. This brings me to the question I posed. If your answers are "it's fun"...."I like the flavor"...."I prefer my ketchup over Heinz"...anything along those lines, you may just have to accept that yours will cost more to produce. Maybe find a way to buy tomatoes in bulk? You might get even closer if you grow your own tomatoes. Even then, the cost would likely be more when you take all of the production variables into account. Any "stretching" will change your recipe, probably at more cost, possibly at risk to the flavor you have developed. If you are trying to make ketchup to save money, there are probably more impactful home financial strategies you could employ.

  • Thanks for the answer. My main reason is to make it healthy, actually. Heinz has high levels of sugar/corn syrup and I figured if I made it fresh, the tomato taste would be a lot more flavorful and less sugar would be required to make the ketchup taste good.
    – user60513
    Commented Aug 4, 2017 at 1:09
  • 1
    The thing that makes the ketchup made with fresh tomatoes taste good is.... sugar! Natural sugars in the tomatoes that is. If reducing the sugar levels is your goal then you might want to look at artificial sweeteners.
    – GdD
    Commented Aug 4, 2017 at 8:33

Honestly, if you want good homemade ketchup you don't stretch it, if you dilute it or cut in lower quality ingredients the result won't be as good. However, $4.50 is a lot for a can of tomatoes, my suggestion is to use tomato paste and add water rather than use canned tomatoes. Tomato paste is not as good a flavor as canned tomatoes but it is far cheaper, and all the major brands use it as a base. A thickener/stabilizer will help to keep the mix integrated.

I've never made it myself but here's a recipe for ketchup using all paste. You could try a 50/50 mix of fresh to paste and see if that makes a good balance between price and flavor.

One thing I wouldn't use is corn syrup, it isn't going to help thicken anything any more than sugar and it doesn't add any character.

  • Hi, thank you for the answer (and for that recipe). Can I ask you a question? What is the role of water in ketchup? It seems to me that by adding more water to the paste the final reduction of the sauce will be longer (in order to get the same consistency) and thus not make any difference in the final product.
    – user60513
    Commented Aug 4, 2017 at 1:15
  • If you are using paste the only role of water is to thin it out. Once you get the desired consistency you stop adding it.
    – GdD
    Commented Aug 4, 2017 at 8:31
  • I agree with using tomato paste, but I used a different recipe and skipped/neglected to read the corn syrup, molasses and water part. I just mixed the rest in a pot and heated it to a simmer to meld the flavour and then turned the pot off. allrecipes.com/recipe/145549/in-a-pinch-ketchup Commented Aug 4, 2017 at 17:32

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