Can anyone give me an idea of which tomatoes are 'low acid?' I had a customer come to the market last spring looking for low acid tomatoes to plant, and I had no idea what to suggest. She named 'Early Girl' as one, but we were out at the time. This is mostly to satiate my curiosity, this question has been bugging me for a year. I'm not much of a tomato gardener (not yet anyway. . .) so I have absolutely no idea.
Some people want them because they are prone to ulcers (like me). But I just can't give up the flavor--I still sneak in some "real tomatoes" every so often--I just have to be careful not to eat too many :-}
They are not necessarily less acid, just have more sugars which mask the acidity. http://www.extension.org/faq/5493 http://www.herald-mail.com/?cmd=displaystory&story_id=118631&format=print
From Texas A&M (TAMU) "A. There are some varieties that are slightly less acidic than others, but this difference is so slight that there is no real difference in taste or in how the tomatoes should be processed. Some yellow-fruited types are slightly less acidic than the normal red varieties, but not enough to make any difference. Research conducted by the USDA indicates that all varieties available to the home gardener are safe for water bath processing as long as good quality fruit are used. Flavor differences which exist between varieties are not because of differences in acid content, but balances of the sugar to acid ratio. http://aggie-horticulture.tamu.edu/plantanswers/vegetables/tomato.html
From the University of Minnesota: "Researchers at USDA and at the University of Minnesota have found that most underripe to ripe, cooked tomatoes have a pH below 4.6. Unfortunately, a few varieties may have a pH above or close to 4.6. These include Ace, Ace 55VF, Beefmaster Hybrid, Big Early Hybrid, Big Girl, Big Set, Burpee VF Hybrid, Cal Ace, Delicious, Fireball, Garden State, Royal Chico, and San Marzano. Some of these are grown for commercial purposes and are not found in home gardens. However, safely canning these varieties requires additional acid for water bath processing or a pressure canning process similar to low acid vegetables. http://www.extension.umn.edu/distribution/nutrition/DJ1097.html