I have heard that it is unsafe to can overripe tomatoes?
Selecting tomatoes that are safe for home canning is of primary importance: Use only firm, ripe tomatoes. Never use overripe tomatoes because they lose acid as they ripen; freeze them instead. Never use tomatoes with soft spots or decayed areas; cutting out soft or moldy spots will not make tomatoes suitable for canning. Never can tomatoes picked from frost-killed or dead vines.
Barbara Willenberg, Nutritional
Sciences, University of Missouri-Columbia
Last update: Tuesday, May 05, 2009