I'd like to can some homemade tomato paste with my pressure canner. I prefer to can under pressure because of the reduced time required & increased safety due to higher processing temps. However I have only been able to find recipes and research for water bath canning of tomato paste. I've found pressure canning recipes for tomato puree and whole tomatoes, but not paste.

Does anyone know of a recipe or research for pressure canning tomato paste? What are some of the factors to consider? Does the reduced water content of paste affect necessary processing time or temperature?

  • Regardless of whether pressure cooking recipes for tomato paste have been developed or not, your assumption is incorrect. You neither get reduced time (that is sometimes the case for pressure cooking, not pressure canning) nor increased safety between a proper water bath canning recipe and a pressure cooking recipe for the same item. The time under pressure is likely to be shorter, but that's a small fraction of the processing time, and also the time spent heating the canner to the start of the processing time is longer.
    – rumtscho
    Sep 7, 2020 at 16:45
  • @rumtscho - I pressure can lots of things. I don't understand why you're saying that - the processing time is definitely shorter. In either case there is lead time to heat the water. The pressure cooker adds 10 minutes venting time and the time to bring up to pressure, but the total time is still less than a water bath. Also, higher temps kill more stuff, that's a given and is the reason why you need a pressure canner to safely can low acid foods. It might be off topic at this point but perhaps you would care to elaborate on why you have this opinion? Sep 7, 2020 at 23:03
  • @billynoah I also do both water bath canning and pressure canning, and on average, it doesn't seem that the whole process is noticeably shortened when using pressure canning - maybe for something like dry beans, but I have never canned those. Usually, the difference is tiny, and tends to be "eaten up" by the longer preheating and the venting time. As for the safety, it is pretty much binary in canning: you either manage to kill all pathogens and have safely preserved food, or you don't. Sure, in cases where a food cannot be canned in water bath, say meat, you technically have a difference...
    – rumtscho
    Sep 8, 2020 at 13:48
  • ... in safety: not safe if you do it in a water bath, and safe if you do it in a pressure canner. You can technically call this an "increase in safety". In this specific case, water bath canning is sufficient. This means that there is no increase in safety between a working water bath canning recipe and a hypothetical pressure canning recipe for tomato paste - both are equally safe.
    – rumtscho
    Sep 8, 2020 at 13:51
  • @rumtscho - thank you for your input and for clarifying. I am not adding citric acid. My understanding is that to safely can tomatoes without the added acid you need the increased temps of pressure canning. I realize this is a slightly controversial subject and I've read a bit of the history behind the reason we are supposed to add acid - primarily a bunch of people getting botulism back in the 70s. At the moment, I'm still looking for a researched recipe for pressure canning paste. It seems to possibly not exist... Sep 8, 2020 at 14:29


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