I was chatting with a friend the other day — one of those endless philosophical conversations about what we know and how we know it. You know, answering the vexing questions of mankind on the way to the gym.
Suddenly, she looked at me: “I stopped believing in science when I found out they say the tomato is really a fruit.”
Knowing her fondness for provocation (and my own ridiculous inclination to lecture on all things even tangentially culinary), I wasn’t sure whether she was quite serious.
So I replied with a line from my favourite rugby-playing philosopher: “Knowledge is knowing that a tomato is a fruit; wisdom is knowing it doesn’t belong in a fruit salad.”
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Tomatoes can be many things to many people, but to botanists, of course, they are a fruit. Because they contain seeds. And if my friend was shocked by the tomato as fruit, I can only imagine what her reaction would be to learning that so many of our other favourite summer vegetables are fruits as well.
Aubergines, hard- and soft-shelled squashes and peppers are all, technically, fruits. (So what, you might well ask, are vegetables? Anything that comes from the roots, stalks or leaves of a plant.)
And as fun as it is for me to wax pedantic, this fact is of more than academic interest. That’s because true vegetables are more or less fixed identities — we consume them in the same state in which they’re harvested. Storing them is simply a matter of putting off decay, and that’s easily done tightly sealed in the refrigerator.
Fruits, on the other hand, can be shape-shifters. Some of them are fairly fixed, at least culinarily. But others can be used at widely different stages of maturity and ripeness.
Consider the courgette, a prime example. We eat them as flowers (lovely stuffed with goat cheese and deep-fried). When the fruit is finger-sized and you can nick the skin with your thumbnail, they can be eaten raw, dipped in olive oil. A little bigger and they need to be cooked to soften and reduce the excess moisture. Even when they are the size of your forearm, they’re wonderful stuffed and baked for a long time in tomato sauce.
Some vegetables change dramatically depending on ripeness, not age. Those gorgeous red and yellow peppers in the market were simply green ones just a few weeks ago. (One of my favourite fun facts: peppers turn from green to red for much the same reason tree leaves change colour in the autumn — the dominant chlorophyll green fades, revealing the underlying colours that have been there all along.)
But perhaps none of our summer fruit/vegetables are as changeable as the tomato. That’s because not only is it a fruit, it’s a climacteric fruit, meaning that it will continue to ripen after it has been removed from the plant. In that way, a tomato is closer to a peach than it is to an aubergine.
Yes, you can harvest a tomato that appears to be pure green and it will eventually turn a ripe red. Whether it will have that rich tomato flavour we crave depends on just how late it was picked. Remember, maturity and ripeness are different — maturity is the fruit collecting the building blocks of flavour and ripeness is when it puts it all together.
Of course, it’s not quite as simple as just letting that tomato sit there and wait patiently. Well, actually it is. The hard part is overcoming some bad habits.
First among these, by a long shot, is our tendency to regard the refrigerator as the ultimate storage space for all fruits and vegetables. Chilling a tomato before it is fully ripe reduces the volatile chemical compounds that make up much of tomato flavour.
Now obviously, this is advice that needs to be taken with a pinch of salt (preferably with basil and olive oil, too). If you have somehow managed to find dead-ripe tomatoes, already softening and fully fragrant, you’ll probably need to refrigerate them before they fall apart (allowing them to come to room temperature before eating will help).
But any tomato short of one of those unicorns should be treated the same way you would treat an under-ripe peach. Place them in a paper bag and leave them on the counter. I should add: leave them in an inconvenient, prominent place on the counter. Because you’re going to want to check in on them a couple of times a day. You’d be surprised how quickly those things will ripen if no one is watching (I know I have been).
Other summer fruit/vegetables aren’t nearly as temperamental. Courgettes, peppers and aubergines won’t continue ripening after they’ve been harvested, so buy the best you can find (hint: look for firm examples that haven’t begun to lose their moisture).
Neither are these fruits as sensitive to chill damage in storage, at least not in the short term. Only if they’ve been forgotten in the fridge for a week or so will you start to notice the formation of some pitting and soft spots.
I’m not sure what the philosophical implications are of all of this are. Granted, Brian O’Driscoll was right: knowledge is not wisdom. But I believe they sometimes do rhyme.
