Tomatoes tend to be in the news either because they became expensive due to complex economics reasons or get wasted in large quantities at an annual festival in Spain. For almost two centuries after they arrived in Europe from the Americas, no one ate tomatoes because they were assumed to be poisonous, but at some point in the 17th century, they quickly became the centrepiece of most Mediterranean cooking and thanks to colonialism, spread to every part of the world. They arrived in India with the Portuguese and, along with chillies, Solanum lycopersicum (wolf peach in Latin), conquered the subcontinent with its ability to bulk up gravies, add mild sourness and lots of umami.
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Botanically speaking, tomatoes are fruits, except the US supreme court, in its Nix v. Hedden judgement of 1893, declared them to be a vegetable for the purposes of calculating import duties on the basis of a simple question—“Is tomato served as dessert?”
Let’s get right down to the science of this remarkable berry. Berries are fruits that tend to be brightly coloured, juicy, round, sweet, tart, and have small seeds instead of a single stone or pit. The tomato plant uses poisons like tomatine and solanine to defend itself against microbes and insects but the fruit itself contains no nasty stuff. It is mostly water (95%) and the rest is a mix of acids like malic and citric acids, glutamates (of MSG fame), and other micronutrients like vitamin C and lycopene, which lends it its characteristic red colour. Contrary to popular myth, cooked tomatoes are more nutritious than raw ones (true for carrots as well).
It is not surprising that tomatoes exploded in popularity in the subcontinent given that outside of coastal, hill and other subaltern communities, umami is not a common component of Indian cooking. High levels of umami tend to come from either slow-cooked bone-in meat broths or seafood. Tomatoes contain quite a large amount of glutamates, particularly when slow-cooked and dehydrated. Umami is one of those tastes that is hard to describe but you know it when you experience it—it lends a savoury, lingering quality to any gravy.
Tomatoes are often grown in combination with alliums (onion, garlic) and mints (basil, spearmint) because the strong aromas of the other plants keep insects away from the tomatoes. This explains why, in almost every cuisine that tomatoes are used, they tend to be paired with onion, garlic and herbs. Most of the tomatoes we eat today are either genetically modified or hybrid, designed to be pest-resistant and high-yield. Non-hybrid, heritage versions are called heirloom tomatoes.
One of the reasons the most widely consumed juice in aeroplanes is tomato juice is that at 20,000ft, our flavour detection apparatus doesn’t work very well because of the low humidity, low air pressure and ambient white noise, so the intensely salty, sour, umami hit of tomato juice works particularly well. At sea-level though, most people find it too intense for a juice but are happy to enjoy a Bloody Mary, a cocktail made from spicy tomato juice and vodka. Alcohol tends to mute tastebud activity, so this seemingly intense combination works just fine.
Some cooking hacks now. Dehydrated (particularly sun-dried) tomatoes are absolute flavour bombs. If you live in a gloomy place, you can use an oven at its lowest temperature setting and dehydrate them over a few hours. Take twice as much tomato as onion, a fair amount of garlic and ginger, coriander stalks and cashews, slow-cook them in butter for 90 minutes and blend it to a paste before freezing it in small silicone cups. You will now have makhani gravy on demand. Just sauté anything else, drop in a cup of makhani paste to get a truly restaurant-style gravy. Pro tip: Add a sachet of ketchup (essentially, concentrated tomato, salt, sugar and vinegar) to any tomato-based gravy to elevate its taste.
When using them in salads, always salt them ahead of time. Both salt and glutamates amplify other flavours, so their combination is spectacular. If you want to make tomato soup like desi restaurants do, realise that the bulk of that flavour comes from celery, onion and carrots. Sweat those in butter before adding tomatoes and then blend and add cream. If you want to avoid cream, just add washed rice grains when cooking the tomatoes down and then blend at the end.
As American writer Laurie Colwin once put it, “A world without tomatoes is like a string quartet without violins”, but it is the Aztecs (from whom the Spanish acquired this fruit) who had quite the most visually descriptive name for tomato itself—Xitomatl. It means “fat water with navel”.
Krish Ashok is the author of Masala Lab: The Science Of Indian Cooking. @krishashok