Canning – Tomato Acidity Is Key
Even small-fruited cultivars, white, yellow and pink tomatoes are in the same acidity range as most standard red tomatoes. The difference in taste of these tomatoes falsely called “low acid” in home seed catalogs is due to their higher sugar content that masks tartness.
Researchers have also found that the acidity level of a tomato variety grown in different soils or in different years may vary considerably.
Paste tomatoes consistently are lower in acid than standard tomatoes. Because of the potential variation in acidity, treat all tomatoes the same whether they be red, yellow or pink.
The United States Department of Agriculture recommends acid to be added to tomato products. Add one tablespoon per pint and two tablespoons per quart. Measure this amount into canning jars before sealing.