How can I test for acidity of tomatoes?
Is there a way to test the pH of my tomato sauce so that I don't have to add the nasty lemon concentrate? If I could avoid adding it, I would like to.
Without the addition of acid (lemon juice, citric acid, or vinegar), tomatoes are not acidic enough to be safely home-canned. You might try citric acid, available in powdered form in stores where bulk products are sold as well as some natural food stores. See page 5 of the following document for quantities: http://extension.oregonstate.edu/fch/sites/default/files/documents/pnw_300_canningtomatoesandtomatoproducts.pdf.
You should be able to obtain bottled lemon juice with no preservatives or other added ingredients at natural food stores. It should be the standard acid level.
We recommend against trying to test the pH of products. There are problems with consistency and accuracy.
Freezing is also an option. There is no need to acidify frozen products.