Originally posted by: Paperdoc
Pickles and the like preserve well because the high acid content prevents bacterial growth. Canning most vegetables, on the other hand, can be tricky because they are low-acid and some bacteria will survive the "sterilization" process of boiling the jars in a canner. That is what pressure canning is for. It runs at a higher temperature (because the pressure of the boiling pot is higher) and guarantees to kill all normal bacteria. Finding a pressure cooker as big as a normal canner pot is tough and very expensive. Our solution was to do pressure canning in our regular large pressure cooker, but to use only pint canning jars (not quart sealers), similar to the size used often for jams etc. They fit the pressure cooker we had. We did beans, beets, stewed tomatoes and few other veggies (not pickled).
Read up closely before starting on tomatoes. At one time is was normal practice to can them with standard boiling water sterilization and rely on the natural acid content of the tomatoes alone to prevent any bacterial growth if sterilization was not perfect. But the popular tomato varieties now used have much lower acid content, and may need the higher temperatures of pressure canning.