For all kinds of home food preservation recipes, tips, state-by-state resources, and research publications, go to The National Center for Home Food Preservation website.

Once there, if you are looking for specific recipes or instructions, use the “Search” tool or “How Do I?” tool on the left side bar. If you have specific questions about processing methods, check out the “FAQs”, also on the left side bar.

If you still have questions, contact the National Center for Home Food Preservation Team at

4 thoughts on “Contact

  1. Suzy Cushman

    If you pressure can at higher pressure than the recipe says, can you reduce the time? And, if so, by how much?

    1. nchfp Post author

      We cannot recommend that you reduce the time in canning foods because you choose to use a higher pressure. There is no formula approach to guide this. In order to know what a process time should be at a certain pressure, heating patterns have to be collected and analyzed at that higher pressure. So it could be unsafe to guess at what a reduced time might be. If you choose to use a higher pressure, you will need to use the full process time as the lower recommendation to insure adequate processing. And then, there would be no value in increasing the pressure/temperature. It would just cause further overcooking of the product and greater loss of nutrients.

      If you are pressure canning low-acid foods, and you guesss wrong, the result could be botulism, a potentially deadly food poisoning. The times and temperatures you find in trusted recipes and procedures are necessary in order to kill any and all microorganisms that could harm the safety of your product. This is especially important in low acid foods which run the risk of botulism from the bacteria Clostridium botulinum. Often overlooked or underappreciated, even the cooling times of heat treatments are calculated into the overall equation of total time needed to assure the safety of the product.

      If you are pressure canning fruits, such as the option found for some fruits normally canned in boiling water, there is already a very short process time at 5 pounds pressure and there would not be a need to increase the pressure to shorten the process time and risk damaging the quality of the fruit or superheating of the syrup that might cause boiling over.

  2. Liz Meimann

    Question about canning tomatoes that have been ripened in the house (because if left in the garden they would freeze). I’ve been told that these tomatoes should not be canned–but nobody can tell me why. If low acidity would be an issue, then wouldn’t pressure canning tomatoes that have been acidified remove the risk.

    1. nchfp Post author

      Yes- whether ripened on or off the vine, tomatoes can be safely canned by following proper recommendations for acidification whether in a boiling water canner or using the pressure canner recommendations. We are not aware of any research that says tomatoes ripened at room temperature have pH values higher than those found naturally across many varieties.

      Tomatoes can have natural pH values that range close to 4.6. Some tomatoes have a pH higher than 4.6, making them a low acid food for canning purposes. Green tomatoes are slightly more acidic than ripe tomatoes, but are not always acidic enough to ensure the safety of the product. Because tomatoes sometimes have a pH greater than 4.6, recommendations for safely canning tomatoes and tomato products are the same whether the tomatoes are green or ripe.

      Also, the USDA procedures for canning tomato products that offer both a boiling water and a pressure canning option (for the same product) are the same amount of heat or sterilization. And acidification is required for both of those options. Those tomato-based products which offer only a pressure process would be an increased level of sterilization, but those that have boiling water and pressure options and require acidification are all the equivalent of a boiling water process.

      The acidification directions can be found here:
      Many tomato product preparations and processes can be found at


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