It isn’t the color that makes a delicious tomato

(Photo by Dion Ogust)

Not that I needed explanations, but now I have two more as to why my tomatoes taste so good. A green thumb is not one of them.

Actually, the explanation is not why tomatoes plucked from my vines taste so good, but rather why the perfect red orbs called “tomatoes” that are dumped onto supermarket shelves don’t taste so good. For this study, agricultural scientist Harry Klee, at the University of Florida, gathered together a whole lot of heirloom and modern tomato varieties and enlisted a whole lot of people to taste and rate them.

Follow-up chemical and statistical analysis pointed the finger at the balance of sugars and acids as one important component of flavor. Modern tomatoes bear so heavily that there are less sugars to go around, so flavor suffers. For a similar reason, I avoid growing “determinate” tomatoes (listed on the seed packet or in the variety description), which are varieties that make flowers and fruits at the ends of rather than along their stems. The determinate growth habit results in fewer leaves per fruit; leaves, along with sunlight, are what put sweetness and other aromas into tomato fruits.

Dr. Klee also found that, besides sugars and acids, heirloom tomato varieties have certain flavor components lacking in modern tomatoes, some of which enhance any sweetness. Geranial, which has a lemony aroma and is used in perfumery, is just one such component; it’s also present in a wild basil (Ocimum gratissimum), orange, lemongrass and of course lemon.

The other bit of pertinent tomato research has to do with color. Nice, on those commercial tomatoes, eh? If you eat with your eyes, the color will make your mouth water. If you eat with your mouth, probably not.

In recent decades, tomatoes have been bred to color up uniformly to a nice red color. Recent research shows that the gene that makes for that uniform coloring was a mutation of a gene that helped make tomatoes flavorful. Before ripening, the uniform-ripening tomatoes are pale green, rather than the deep green of tomatoes without the mutated gene. Dark-green fruits harvest more of the Sun’s energy than light-green fruits; more green means more photosynthesis and more sugars and other flavor components. That ripening mutation, stumbled upon by breeders about 70 years ago, was widely adopted, and has resulted in those beautiful orbs that have lined supermarket shelves for many years.

Using genetic engineering, researchers confirmed their findings by creating tomatoes that stayed dark-green before ripening and then ripened uniformly red. As expected, laboratory analysis showed that the fruits had more sugars and other flavor components than fruits with only the uniform-ripening gene mutation. Nobody ate the “Frankentomatoes.”

The best heirloom varieties also seem to share some superficial characteristics. Potato-leafed (with smooth leaf edges) tomatoes, such as Brandywine and Prudens Purple, generally make tasty fruits. So-called oxheart varieties (pinkish skins and heart-shaped fruits), such as Oxheart, Orange Russian and Hungarian Heart, also are rich and flavorful. The same can be said for dark varieties, such as Black Krim, Black Crimson and Black Prince.

Hybrid tomatoes don’t have to be less flavorful than heirloom varieties. They don’t have to be bred for maximum production at the expense of flavor and/or to ripen uniformly red. But they usually are.

The familiar Sungold and the less-familiar Carmello are two flavorful hybrid varieties in my garden. In my opinion, Sungold is far and away the best-tasting cherry tomato (and also a beautiful persimmon-orange color). Carmello is quite tasty, and actually does ripen into perfectly red orbs.

Nonetheless, for unabashed flavor, whether sliced with onions and olives in salad, laid in slivers on dark bread with cheese or cooked into a sauce, heirloom tomatoes are my number-one choice – which brings me to Cherokee Purple, the first one of which ripened today. It was very tasty and not at all pretty.

August 4: Explore two private gardens in Bearsville and Ulster Park, open to the public for self-guided tours to benefit the Garden Conservancy. No reservations are required, and the tours will run rain or shine. Begin at the Gayle Burbank Garden, located at 203 Cooper Lake Road in Bearsville; or at Ande & Peter Rooney’s Garden at Twin Brook Farm, located at 47 Union Center Road in Ulster Park. The gardens are open from 10 a.m. to 4 p.m. Visit for more info.

Any gardening questions? E-mail them to me at [email protected] and I’ll try answering them directly or in this column. Come visit my garden at

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