Amuse-Bouche: Are Tomatoes Really Fruits? + Eggs in Tomato Sauce

The very funny Zach Weiner published a comic today that mocks people who speak with great authority on topics they know relatively little about, and rightly so. However, one of his example “Phrases uttered atop Mount Stupid” gave me pause: “Biologically, tomato is a fruit, not a vegetable.”

I figured this was common knowledge, and I was a little confused as to why it was included on a list of misconceptions. Maybe because saying so makes you sound pretentious?

I decided to see what is said about the classification of tomatoes by people with actual authority on the subject, and so I turned to Harold McGee.

It turns out that botanists and cooks classify tomatoes differently, and both sides have good reasons for choosing the classifications they do.

Botanically speaking, tomatoes are in fact fruits. McGee defines “fruit” as “the organ that develops from the flower’s ovary and surrounds the plants seeds. (“Vegetable” refers to “plant material that is neither fruit nor seed.”) In general, fruits have a high sugar content and are moister and softer, with complex aromas, while foods we treat as vegetables remain firm, have milder flavors, and typically require cooking to make them palatable. By this understanding, tomatoes certainly seem to fall in the fruit category.

My local market keeps tomatoes with other fruits, but probably because cold storage will damage the cell walls

And yet, we usually eat tomatoes in savory dishes and commonly consider them to be vegetables. Why?

If you were paying close attention to my previous post, you might have a piece of the answer. In addition to having relatively low sugar content, tomatoes are extremely high in glutamic acid, the compound that triggers umami, or savory taste sensations on your tongue, as well as aromatic sulfur compounds. Both glutamic acids and sulfur aromas are commonly found in meats, so it makes sense that tomatoes would complement meaty dishes, as well as replace that flavor and add complexity to meatless items.

McGee also shares the following story:

Even the United States Supreme Court has preferred the cook’s definition to the botanist’s. In the 1890s, a New York food importer claimed duty-free status for a shipment of tomatoes, arguing that tomatoes were fruits, and so under the regulations of the time, not subject to import fees. The customs agent ruled that tomatoes were vegetables and imposed a duty. A majority of the Supreme Court decided that tomatoes were “usually served at a dinner in, with, or after the soup, fish, or meat, which constitute the principal part of the repast, and not, like fruits, generally as dessert.” Ergo tomatoes were vegetables, and the importer had to pay.

So, are tomatoes really a fruit? Yes, but what’s in a name? Along with cucumbers, green beans, eggplants, and corn kernels–other fruits also commonly treated like vegetables by cooks–tomatoes are in delicious company. Hopefully this extra knowledge will help you bypass Mount Stupid.

Seeing as it’s the middle of winter, I’m not about to provide you with a recipe that calls for fresh tomatoes (to learn about everything that is wrong with supermarket tomatoes, I recommend this interview). However, while not a substitute for fresh tomatoes, canned tomatoes are an excellent ingredient in their own right, cooked and preserved when the tomatoes are at their peak flavor. I especially recommend San Marzanos. This recipe adapted from Smitten Kitchen is great for a cold winter evening.

Eggs Poached in Tomato Sauce

Serves 2

Olive oil
1 large garlic clove, minced
Pinch red pepper flakes
14oz crushed or pureed tomatoes, depending on how chunky you want the sauce
Pinch sugar
Salt and pepper
Red wine (optional)
4 eggs

  1. Add enough to olive oil to a small pan to cover the bottom and warm over medium heat. Add the garlic and pepper flakes and cook for one minute, stirring.
  2. Add the tomatoes and bring to a boil. Add the sugar and season with salt and pepper, then lower the heat to medium-low and allow the tomato mixture to simmer for 10-15 minutes. If using wine, add a glug a couple minutes before the tomatoes are done.
  3. Crack the eggs gently one at a time into the tomato mixture. Cover and cook for 5 minutes, until the whites are set, then remove from heat and let sit for 2-3 minutes.
  4. Spoon the eggs in their sauce over thick slices of toast or sauteed greens to serve.

An “amuse-bouche” (which literally translates to “mouth-amuser”) is a complimentary morsel to start the meal, a tasty little gift from the chef. We hope you enjoy these edible tidbits.

Anne S

Anne Sauer is an atheist with an appetite for science, good food, and making connections between the two. She is currently pursuing her MBA in Sustainable Management at Presidio Graduate School in San Francisco. Her favorite foods are salted caramel ice cream and chicken tikka masala. You can find her on twitter @aynsavoy.

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  1. Culinary definition is accepted for historical reason. Like saying ‘sunrise’.
    They should teach is as a savory fruit. A vegetable is any plant matter. i.e Vegetable kingdom.

    I prefer people being correct over catering to historical inaccuracies.

    I will be using the recipe this weekend. Look nummy.

  2. They aren’t incorrect; that’s the point. The word “fruit” has different meanings to different groups of people. A tomato is a botanical fruit AND a culinary vegetable. It gets to be both!

  3. On Twitter, Zach Weiner explains that “all the statements are carefully phrased to be technically false.” It’s the “not a vegetable” part of the phrase that makes it false for him, I think. I was just interested in what a culinary scientist had to say about the classification.

  4. We had slow roasted tomatoes as part of our Christmas feast. Just a little oil, salt, pepper and garlic in an open pan under a mediumish heat for an hour or so. Fantastic. I think it’s the prolonged suffering of the tomatoes that brings out the yummy. 😉

    Oh, and here’s the really mystery: are they toMAYtoes or toMAHtoes?

  5. These cooking/science articles are great. I am really enjoying them. Keep up the great work.

    The recipe does sound yummy! I will have to try it too.

    The food chemistry is really interesting too. I wonder if there is a certain pH where the glutamic acid is optimal in flavor and then goes away when the pH is too high/low. The protonation state changes as the pH changes. Is only one protonation state umami-tastic? I wonder…

  6. coelecanth: That sounds delicious.

    Jacqueline: I’m no chemist so I don’t have a specific answer to your question, but I (or rather, McGee) can tell you that tomatoes accumulate more sugar, acid, an aroma compounds as they ripen on the vine.

    One of the problems with supermarket tomatoes is that most of them are picked while in a state called “mature green” so that they can travel long distances and then reddened artificially using ethylene gas. They look ripe, but they’re not, so they don’t contain all those delicious flavor compounds. Add to that the fact that these mass-grown tomatoes are paid for by weight–not by flavor, so growers have been incentivized to develop high-yield, durable tomatoes rather than focusing on the flavor. I think I remember the author saying in the interview I linked above that when you have a vine producing as many fruits as these do, even if you let them ripen on the vine the plant will have trouble producing enough of flavor compounds to go around.

  7. Oh, a note on ethylene gas: fruit with yellow, orange, or red skins actually produce ethylene gas as they ripen, so the artificial process mimics the natural process. But, it’s just one element of the natural process and not one that contributes to flavor, unfortunately.

  8. Apparently I need to go through a proper peer review process before posting to culinary threads. To wit, a correction*:

    The slow roasted tomatoes are cooked in oil and balsamic vinegar to which any number of spices can be added. Our christmas ones had salt, pepper and cumin seeds I’m told, and I’ve also been sworn to mention that there as a teaspoon of sugar in the mix.** They are to be done in a “slow oven” which apparently is defined and 150c for an hour or two and left in the oven after it’s turned off until they cool. We (and by that I mean my wife) use locally grown vine ripened tomatoes because although they’re still picked green they’re more ripe than the imports. After cooking they will last in the fridge for a goodly time, a week or two if I remember right, so making a big batch and storing the rest for sauces and whatnots is doable.

    *Please note that this is not presented as a real recipe because I’m a hopeless cook and this is all hearsay. I disavow any and all responsibility for culinary disasters present and in the future resulting from any and all attempts to follow what I’ve written here. Youse been warned.

    **I’m calling confirmation bias on this. Considering the amount of oil and vinegar and the number of tomatoes and all the juice they leak I can’t see how that little sugar would make any noticeable difference, but Claire swears by it so there you go. I eagerly await the day when I can do a double blind experiment to test this.

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