Ph Levels, Using homemade recipes for canning

Asked December 6, 2020, 3:09 PM EST

My question is about canning my own recipes. I know the Ph threshholds for water bath canning, high ph v. low ph and when to use a pressure canner, etc. I am havnig trouble finding the answer to my exact question, however.

Can I just test the Ph of my food (my own recipe) and use that to determine if it is safe for canning? I would think I could wait 24 hours after processing, once the food has sat at room temp. and do a test of the product? Follow-up Question: If a pressure canner is what is used for low acidic foods because of the higher processing temperature, couldn't I just always use a pressure canner to process homemade recipes?

All the information I have found states if the Ph is x than it is not safe for water bath canning, and also, "Always use a science-backed recipe for safe canning." My deductive reasoning is wondering then, if a pressure canner is used for recipes not safe for water bath canning, then why can't I use my pressure canner if there is any question of Ph or safety? And finally, if I must always use someone else's recipe so that it is tested and true ("science-backed"), then what is the point of preserving my own food?


Alameda County California

1 Response

Hello.

There is a lot of conflicting information on home canning available, unfortunately, we cannot recommend canning in a home kitchen with a recipe that has not been tested by a recognized authority for the following reasons:

  1. We cannot verify calibration of an individual’s pH meter or proper use of the instrument. We also cannot verify the methodology used for pH testing in a home kitchen.
  2. There is natural variation in pH in products. If a recipe is close to the 4.6 threshold, the natural variation may be enough to cause some batches to exceed 4.6. Thus, a recipe that falls below 4.6 in one batch may exceed it in another batch. Also, certain foods display a greater buffering ability, so it is critical that all portions of product meet the required threshold. Again, we cannot validate testing procedures in a home kitchen.
  3. Low acid foods that require pressure canning for safety are based on certain validated processing times and the processing time varies from product to product based on the composition of the food, the density, heat transfer within the jar and other factors. This is critical to ensure the destruction of botulism spores. Botulism toxin is extremely potent and ingestion is life threatening. I have attached a link with more information on botulism. https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/foodborne-illness-and-disease/clostridium-botulinum/ct_index Just using a pressure cooker is not enough. Processing time is critical and can only be established by rigorous testing.

There are a variety of reasons that people practice home food preservation. If you have a large garden with more produce than you can consume, preserving it through drying, freezing or canning is way not to lose the fruit of your labors. It offers a way of storing excess product for use later in the year. This can reduce food waste and provide an economic incentive for growers. (However, the initial investment should be considered when evaluating economic benefit.) Home food preservation allows you to know exactly what went into the product and how it was processed. Canning offers the added benefit of shelf stability - the food can withstand power outages and is a ready to eat option. Canned items offer an easy, convenient option for quick meals as a significant portion of the preparation time has already been invested.

It is obvious that you have put considerable time and effort into producing a safe product. Just remember, this is America, you can do your own recipes, and if not sure, then the recommendation would be to pressure can using a tested recipe similar to your own product (ingredients, amounts, etc.). If you need further assistance, please do not hesitate to reach out to Ask Extension again Good luck.