Tomatoes 101

A Fruit That's a Favorite Vegetable

Sources: Field Guide to Produce by Aliza Green; On Food and Cooking by Harold McGee; Brooklyn Botanic Garden

How should I choose a fresh tomato?

Whether buying a beefsteak, heirloom, plum, or a stem-full of cherry tomatoes, look for ones that are firm and without any bruises.  Sometimes an heirloom or other locally grown tomato will have a split in the skin, but look carefully because the split may have occurred while it was growing and it is only on the surface, meaning there's a perfect tomato underneath.  Try to know where a tomato was grown because local is always better.  Despite a pretty outward appearance, an imported tomato is usually tasteless and was ripened in some warehouse.  Finally, give a tomato a sniff.  If there's a subtle, sweet garden smell, it's likely this tomato will actually have taste.

Are fresh tomatoes good year-round?

It depends.  While we can buy fresh tomatoes year-round, the local growing season is July to October; the rest of the time most fresh tomatoes are greenhouse-grown and tasteless.  In the winter your best choices are plum (also called "Roma") tomatoes for oven-roasting or making sauces, and cherry tomatoes for pan cooking and salads.  Look for cherry tomatoes still on the vine and buy ones that are firm and round.   When cooking with tomatoes, canned imported San Marzanos can be a happy alternative or even a superior choice to a tasteless mid-winter fresh tomato (see our article about San Marzano tomatoes).

What about those beautiful red imported tomatoes I see in the markets year-round, with three or four in a cluster on a vine?  If they look so good, they must taste great, right?

Probably not.  These are hot house tomatoes, meaning they were grown and ripened indoors in a controlled environment, and most hot house tomatoes have no flavor.  A fourth of all tomatoes sold in the U.S. are now hot house-grown, many imported from Canada, Israel and the Netherlands.  If their appearance seduces you, their taste will probably not and you won't buy them more than once.

Tomatoes were the first genetically engineered food approved by the U.S. Food and Drug Administration, letting scientists alter the ripening gene in tomato seeds, letting these tomatoes ripen on the vine longer so to be firmer and thus more robust to ship long distances.  Who wants to eat anything like that?

What is an heirloom tomato?

The term heirloom is sometimes vaguely and imprecisely used to describe any unusual looking type of tomato.  In fact heirlooms are open-pollinated varieties that are at least 40 to 50 years old and that self-fertilize.  In other words, these are true varieties that haven't been cross-polinated to create a hybrid variety.  Some of the most popular are and distinctively looking are the yellow Taxi tomato, Green Grapes, the fuzzy Peach, White Queen, and Black Krim.

What is a grape tomato?

Grape tomatoes are a hybrid of the cherry tomato.  With the size and shape of an olive, grape tomatoes are sweeter -- they have more sugar -- and less juicy than a cherry tomato.   They are great for snacks, especially because they're bite-sized and don't squirt out juice when bitten into.  But they are not as flavorful or juicy as cherry tomatoes for salads or in cooking.

What's the best way to peel a tomato?

There are two ways.  The most common is to drop a tomato into a pot of boiling water for 30 or so seconds.  Lift the tomato out of the water with a slotted spoon and gently run a fingernail along the skin.  If the skin wrinkles and seems loose, remove the tomato from the hot water and place it in a bowl of iced water to stop the cooking.  Drain and use a paring knife to peel the skin off (it should come off easily).

Be careful to not leave the tomato in the boiling water for too long because it will begin to cook, creating a mealy, soft surface right under the skin.

The other way to peel a tomato is with a serrated knife or vegetable peeler, although this method works best when the skin is a bit thicker, giving the knife or peeler something to hold on to.

Should I own a special tomato knife?

Tomatoes are best cut with a serrated knife which makes it easy to cut through the skin without crushing the fragile flesh and interior.  A serrated bread knife works perfectly for this task.  Small, serrated tomato knives are sold and are very convenient if you frequently cook with tomatoes.  Or if you have the room to collect single-purpose knives.

Why are tomatoes never refrigerated?

Tomatoes should never be refrigerated.  Instead, store them at room temperature -- they can stay for days on a kitchen counter.  If you refrigerate a tomato you will wreck its flavor and also cause its texture to become mealy.  That's because tomatoes are originally from a warm climate and anything chilly will damage their membranes and the flavor-producing enzymes.  If you need to store a cut tomato, it's best to wrap it in plastic wrap and leave it on the kitchen counter, not in the refrigerator, eating it within 24-hours. 

Is a yellow tomato still a tomato?  Do they taste the same?

Yellow tomatoes are lower in acid than red tomatoes, making them a good choice for people who have trouble eating a more acidic red tomato.  They do, however, have a paler flavor.

How many calories in a tomato?

Rich in vitamin C and other nutrients, tomatoes are low in calories.  A medium raw tomato, weighing about 120 grams or if cut, equal to about a cup, has only about 30 calories.  They have no fat, no cholesterol, and are low in sodium.  

Is it true that tomatoes were discovered in the New World but perfected by Italians?

The Spanish discovered tomatoes in the 16th century and brought them back to Europe.  In fact the English word tomato comes from the original Aztec name tomatl, or "plump fruit."  When tomatoes were first brought to Europe some people believed that they were deadly poisonous, but fortunately Italians, who turned tomatoes into the brilliance of ragu, did not.  Today tomatoes are the second most popular vegetable, with potatoes being number one.

So is a tomato a fruit or a vegetable? 

Harold McGee's masterful On Food and Cooking categorizes it as a vegetable but refers to it as a fruit treated as a vegetable, putting it in the "Nightshade" plant family.  Not exactly clear, but then again, does it really matter?