Canning Food Acidity: High pH and low pH Foods

Canning - Food Acidity
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Canning – Food Acidity

Canning is not only a great way for one to be self-sufficient, but canning is also a great hobby that is both rewarding and fun. Though joining the world of canning can be an exciting venture, the process of canning is also quite sensitive and you must always exercise caution as well as arm yourself with sufficient canning knowledge to do it properly.

Food preservation at home can only be safely done using a pressure canner or a boiling water bath. The technique to utilize is typically determined by the pH level of the food item to be canned. Foods that have a low pH can only be canned using the water bath technique while high pH foods are generally preserved using a pressure canner.

Canning – Food Acidity

Understanding the difference between high pH and low pH foods or rather, the difference between acidic and non-acid food is the most important thing that a beginner home canner can do before they delve into the glorious world of food canning.

What exactly is pH?

pH is the measuring unit that is used to determine how acidic something is or is not. The pH scale is measured from 0 to 14 with 14 being the least acidic level and 0 being the most acidic. The neutral pH level, which is the middle, is 7.

High acid and low acid foods

High acid foods are foods that contain a pH value of 4.6 or lower. Low pH food stuffs can be processed and canned safely through a perfect boiling water canner. The high acidic content in these foods creates an acidic environment that is not conducive for most yeast, bacteria, and fungi to grow.

Since the acidic environment is sufficient enough to effectively prevent the growth of food spoiling bacteria, common food spoilage agents are then easily destroyed by the temperature of boiling water, which is why a water bath canner is used to process high acidic foods. Examples of high acidic foods include fruits and anything derived from fruits, juices, as well as pickled and fermented foods.

Although tomatoes are considered high acid foods, some strains of tomatoes are known to have pH values that are slightly above 4.6. Because it is sometimes impossible to tell, you must always add an acidic agent such as lemon juice to canned tomatoes or canned tomato products. Doing this ensures that the tomatoes contain enough acid for them to be processed safely in a boiling water canner.

Low acid foods

Low acid foods, on the other hand, are foods that have a pH value ranging from 4.6 to 6.9. Nonacidic foods or alkaline foods typically have a pH value of 7. Low acid foods provide the perfect environment for food spoiling bacteria to thrive. As such, all foods with high pH need to be well processed and in a good pressure canner, as it is the only technique capable of producing enough heat to kill botulism bacteria. Examples of low acid foods include meat, veggies, and fish.

When low acid foods and high acid foods are mixed together for canning, the resulting mixture is said to have a pH level that greater than 4.6 and this mixture, therefore, requires the use of the pressure canning technique to produce safe results.

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