Depends on the tomatoes. sadly, many (most) that we buy today are lower acid and need to be pressure canned as well. So annoying!
Frightening Canning Procedures
- Thread starter cmzaha
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Not all tomatoes are high acid!
I can't use citric acid because of the sulfite residue from processing. I'd rather be safe than sorry.
I can't use citric acid because of the sulfite residue from processing. I'd rather be safe than sorry.
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A water bath canning method is fine for many tomato-based foods -- not sure why there's the perception that tomatoes HAVE to be pressure canned. Some tested recipes provide a water-bath method AND a pressure-canning method for tomatoes -- you pick which one you want to use. Both methods will require you to add acid to the tomatoes to ensure the pH is low enough. The low pH takes care of the safety issue.
List of tested recipes, some with water bath and pressure canner methods: https://www.healthycanning.com/list-home-canned-tomato-product-recipes
More discussion about acidification for tomatoes: https://www.healthycanning.com/why-do-some-tomato-products-need-acidification-but-not-others/
The idea that modern tomatoes are less acidic than heirloom tomatoes has been debunked. The pH of heirloom tomatoes is in the same general range as modern tomatoes. Here are some numbers:
"...The University of Wisconsin Extension tested the pH of 55 heirloom tomato cultivars.... The pH of the mature tomatoes ranged from 4.18-4.92. (Remember, the safe cut-off upper maximum is 4.6. Anything above that is considered low-acid.) 27% of the heirloom tomatoes had a mature pH of 4.6 or higher including Brandywine, Ace, Big Early Hybrid, and Big Girl....
"...The pH of tomato varieties can range from an acidic low of 3.8 to a much less acidic pH of 4.7. The story goes that as the consumer has demanded a less acidic tomato, hybrids have been developed that taste less acidic—but some argue that this is due to more sugar in the tomato, not less acid. Would that mean that older heirloom varieties are likely to be more acidic? Not necessarily....
"...In your home garden, a number of factors can influence the pH of even the more acidic tomatoes: these include soil, vine health, ripeness...."
Source: https://www.healthycanning.com/heirloom-tomatoes-acidity/
List of tested recipes, some with water bath and pressure canner methods: https://www.healthycanning.com/list-home-canned-tomato-product-recipes
More discussion about acidification for tomatoes: https://www.healthycanning.com/why-do-some-tomato-products-need-acidification-but-not-others/
The idea that modern tomatoes are less acidic than heirloom tomatoes has been debunked. The pH of heirloom tomatoes is in the same general range as modern tomatoes. Here are some numbers:
"...The University of Wisconsin Extension tested the pH of 55 heirloom tomato cultivars.... The pH of the mature tomatoes ranged from 4.18-4.92. (Remember, the safe cut-off upper maximum is 4.6. Anything above that is considered low-acid.) 27% of the heirloom tomatoes had a mature pH of 4.6 or higher including Brandywine, Ace, Big Early Hybrid, and Big Girl....
"...The pH of tomato varieties can range from an acidic low of 3.8 to a much less acidic pH of 4.7. The story goes that as the consumer has demanded a less acidic tomato, hybrids have been developed that taste less acidic—but some argue that this is due to more sugar in the tomato, not less acid. Would that mean that older heirloom varieties are likely to be more acidic? Not necessarily....
"...In your home garden, a number of factors can influence the pH of even the more acidic tomatoes: these include soil, vine health, ripeness...."
Source: https://www.healthycanning.com/heirloom-tomatoes-acidity/
