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'Low Acid' Tomatoes


Q. Where can I buy acid free tomatoes? I want to get started on my tomatoes and need acid free varieties. (I love tomatoes but get a cold sore from regular ones.)
    ---John in Romulus, Michigan ("Near Detroit Metro airport")
Mike: As age catches up to me (you'll be there someday) I've been developing some stomach problems. Can you recommend a reduced-acid or low-acid variety of my favorite fruit, the tomato? Or is this an oxymoron? I love tomatoes, but alas, like chocolate and citrus, they don't seem to love me anymore. Thanks,
    ---Jim in beautiful downtown Glenside, PA
A. Jim: Thanks for the nice thought, but that 'someday' hit me long ago! I didn't listen to the advice of the great Satchel Paige, looked behind me, and boom—I was a geezer. Now, John: There is no such thing as a 'no-acid tomato'. And despite LOTS of interest in 'low-acid' love apples, little real information exists on the subject, with varieties being specifically designated as such much less often than you might expect. But let's discuss a few I did find when I first researched this topic back in '03.

All of the members of the 'Sweet' series of cherry tomatoes are felt to be low-acid, especially "Super Sweet 100", a red cherry tomato that, when introduced, was described as "a new hybrid of the low-acid 'Sweet 100' variety". (MANY improved varieties of the classic Sweet 100 have been released, all the way up to an inflationary "Sweet Million".) "Yellow pear", a cute golden variety that's slightly larger than a cherry but shaped more like a pear (hence the name), is also said to be low-acid; as is "Caro Rich", a medium-sized (4 to 6 oz.) orange-red slicer that's also bred to be especially high in Vitamin A.

Varieties with the word 'Ace' in their name might also be a good bet, like "Ace 55", a red tomato that was originally catalog-described as being "lower in acid than most other tomatoes and often recommended to people on a low-acid diet." Obviously not red, "Golden Sunray" is described as a half-pound heirloom with "a rich, 'not too acid' taste".

I'll personally add "Georgia Streak", a HUGE yellow heirloom that develops a red blush throughout the entire fruit as it ripens. My fresh-tomato friends (fiends?) consider it very low acid in taste, and it's certainly the SWEETEST tomato I've ever grown. The also-heirloom varieties "Big Rainbow" and "Marvel Stripe" are very similar in appearance. In fact, according to Amy Goldman's excellent book, "The Heirloom Tomato" (Bloomsbury; 2008), the variety that I've been calling Georgia Streak all these years is more likely to actually be one of the 'Marvel's. I'd trust her—she researched dozens of old seed catalogs looking for the original listings of each variety when they first appeared to try and pinpoint the true names of these hand-me-down treasures.

You'll note that most of these tomatoes are yellow/orange/gold, or at least streaked with one of those non-red hues. These 'other color' tomatoes have long been associated with 'low-acid' flavor. Ah, but many yellow/gold varieties are VERY sweet. Could it be that people just perceive their high sugar-to-acid ratio as tasting "low acid" when it's really some extra sweetness they're sensing?

Amy Goldman thinks this may well be the case, but adds that she doesn't personally care for low-acid love apples for the very same reason. "In my book, I rate 'low-acid, high-sugar' tomatoes as only 'poor to fair' tasting. And when a tomato is low in both acid and sugar, it's downright bland. So most people will find the taste of these types of tomatoes only mildly pleasing and refreshing—at best," she told me during a recent snowstorm that had us both dreaming of summer tomatoes. "The best flavored tomatoes are both high acid and high sugar; that's the combination people are looking for in an excellent fresh eating tomato."

That said, Amy adds that some low-acid tomatoes do have other desirable traits, like cold hardiness, early ripening and productivity. Asked to name some low acid varieties profiled in her book, she cited Brown Berry, Moneymaker, Bonny Best, King Humbert, San Marzano (a paste/plum-style tomato that I often grow in my own garden, both in its original form and in improved varieties like Super San Marzano), Yellow Pear, Banana Legs and Persimmon (which we can only hope tastes nothing like the astringent tree fruit of the same name).

Now, in addition to her 'Catalog Archeology' research, Amy scientifically measured the sugar (brix) levels in the hundreds of different tomato varieties she grew over a several year stretch, listing the results in her individual variety descriptions in the book. But she explains that she 'measured' what she calls 'perceived acidity' the old-fashioned way—by taste, looking for "that wonderful, tongue-tingling, mouth-watering component". So while we know a lot about actual sugar levels, acidity is more of a perception (which I think is preferable to measurement sometimes).

So my suggestion to Jim is to try a variety of varieties—some that I've named and some gleaned from Amy's list and the others described as low acid in her book—grow them out this summer and sample them. Hopefully, you'll find a few 'non-mouth-watering' varieties that agree with you.

Ah, but John in Michigan may have something completely different going on. People who are allergic to certain seasonal pollens often have what's called 'itchy mouth syndrome' when they eat certain fruits whose proteins seem similar to those pollens to the person's over-active immune system. Although I suspect this is a very common condition in the U.S., it seems to be little known to physicians here. But it's well documented in European medical journals (where I originally learned about it).

When such an allergy is the cause of a tomato reaction, the only real cure is cooking. Food allergies are weird; sometimes—as with shellfish—heating concentrates the proteins responsible for the reaction and makes it worse. But sometimes, heating denatures the proteins and the otherwise allergic person can consume the cooked culprit safely. This seems to be case with itchy mouth caused by fruits like tomatoes.

So John—try making a batch of tomato sauce and see if your mouth still reacts. If fresh love apples continue to cause problems, but the same ones don't after being cooked, it's not the acidity that's bothering you—it's the proteins.

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