all food is actually water

to a first approximation

The great drawing teacher Robert Beverly Hale once wrote

Students always feel that they can make a good drawing if they have enough time. But these marvelously rapid sketches of Rembrandt may teach you that it is not time that makes a good drawing, but understanding.

I feel similarly about Indian cooking. It is not time, nor expensive ingredients, nor even love, that makes for good food, but understanding.

sneaky grandmas claiming that love is the most important ingredient when in fact they’re deploying decades of tacit knowledge and have the burnmarks to prove it

Where to begin? There is much to understand when it comes to cooking, but for Indian cooking the answer is easy: we must study how water behaves when it’s heated. I know it sounds boring and you want to get to the exciting topics (spice combinations! tadkas! gravies! umami bombs! tikkas!). But before we get to sexy stuff we’ll need some physical chemistry.

not this kind of physical chemistry in the kitchen

facts you need to know about water

You must deeply and intuitively come to understand the following facts:

1. Upon heating, the temperature of water will rise until it reaches its boiling point (212 F), and then it’ll stay there until it’s all evaporated and gone. Liquid water hangs out at that boiling temperature. Turning up the heat will make it evaporate faster but won’t actually make it hotter.

2. If water is liquid then it’s just not that hot: the boiling point of water is way lower than the temperatures at which things burn, brown and caramelize. And if water is liquid then it is, by definition, at or under its boiling point.

3. It takes a fuckton of energy to heat water, so adding even a small amount of liquid will immediately bring down the temperature of whatever’s in the pan. And it’ll take a while to heat back up to boiling point and then evaporate away.

4. Many raw ingredients are mostly water: vegetables, fruit, meat, herbs, dairy products. It is no accident that things that don’t have water often have “dried” in their name. So when you add a some sliced onion to a pan, you’re kinda just adding a bunch of water.

5. Anything immersed in hot water is gonna get hot pretty fast. The fancy way of saying this is that water has relatively high thermal conductivity, which you might find surprising if you’ve been in physics class and thinking about metals. But compared to edible oils, vegetables or especially air, water is a brutally good thermal conductor. That’s why you roast chicken at such a higher temperature than 212 F, yet it takes longer to cook than stewing. Imagine sitting in a steamy sauna versus being boiled alive. The temperatures involved are similar!

some things are too serious to be joked about, which is why this image caption contains no jokes

The items in that list are ordered by importance, and the first thing is just way more important than everything else. If you remember only one thing from this blog post, it should be the graph above: when you add heat to liquid water, it’ll eventually reach its boiling point and then stay there until it’s all evaporated

Why do you need to know this stuff? These are the elements of a core skill that I like to call moisture awareness and control: knowing how much water is in the pan, how that water is distributed, how hot the food is, what you want the temperature to be, and what to do to get it there. Enough theory! Let’s do some examples.

example 1: tempering whole spices in oil

You heat oil in a pan. The oil starts shimmering, expressing how hot it is, how excited for you to swallow it tonight. You throw some mustard seeds in the oil. The seeds quickly swell, sizzle, pop and brown. They smell good. Some brown more than others, starting to look burned. Panic rises in your chest but you’re prepared for this moment. You’ve been ready since before turning that stove on. You’ve been ready for years. You throw some diced tomato in the pan and stir. The popping stops immediately. You sigh with relief and continue with the rest of the dish.

this is the Rembrandt drawing that Robert Beverly Hale was talking about in that quote. It’s called Girl Sleeping, probably his wife Hendrickje Stoffels.

What happened here: oil can get a lot hotter than the boiling point of water, and mustard seeds are small and dry, so the temperature of the oil-plus-seed-combo was pretty high. The seeds were about to burn. But tomatoes are really juicy (fact 4 from the list). That juice mixed with the oil and cooled it to, roughly, whatever temperature the tomato was. Now the pan has a high water content and that means it won’t get to those hot burn-y temperatures (fact 2 from the list) until all the tomato juice has evaporated away (fact 1). But it takes a while for water to heat up (fact 3) so you’ve bought yourself a bunch of time to continue with the rest of the dish.

example 2: cooking rice on the stovetop

why spend $30 on a rice cooker when you could spend 3 years developing excellent moisture awareness instead

You mix 2 cups of rice with 4 cups of water in a saucepan. You bring to a boil and reduce to a simmer. You cover it with a lid and then go about your day, messing around on your phone or whatever. You forget to set a timer. Time passes, inexorably bringing you closer to death: eternal oblivion, or perhaps a meeting with The One You’re Bound to Face. Sniff sniff you smell a warm toasty crunchy smell! Panic rises in your throat but you’re prepared for this moment. You’ve been ready for years. You spring into action: you turn the sink faucet on and cup your palm under it. You throw this tiny splash into the saucepan. You scrape the bottom with a spoon, finding some resistance but not stubborn recalcitrance. You see that the bits that used to be at the bottom, now mixed with the body of the rice, are brown but not burned black. You sigh with relief, turn off the burner, and leave the lid off. You go back to your phone.

What happened here: the water at the bottom of the saucepan evaporated away. After a while, the material inside the saucepan is mostly rice and steam, which are poor conductors of heat (fact 5 from the list). So the bottom of the saucepan, now devoid of liquid water, started to get a lot hotter than the boiling point of water (fact 1), eventually reaching temperatures where browning (Maillard) reactions can occur (fact 2). The small splash of water goes right to the bottom and cools it down (fact 3), while mixing physically distributes the hot burned bits across the bulk of the rest of the rice, cooling them down.

example 3: sauteeing aromatics

You heat oil in a pan. The oil starts shimmering, expressing eager readiness for what it knows is coming: you throw some cumin seeds in the oil. The seeds swell, sizzle and brown. They smell good. You throw some sliced onions in the pan and stir well, distributing the cumin seeds and oil evenly. You add a generous pinch of salt and stir again. Some water seeps out and pools around. It soon steams away and the onions begin to brown. You add ginger and garlic. You stir a little more. You add tomatoes. You stir some more. The mixture gives off steam. Eventually it stops steaming and you see little bits of oil pooling next to the mixture. The oil appears to sizzle. The mixture begins to take on a darker color. It smells good. You allow yourself a secret smile and proceed with the rest of the dish.

what’s the use of studying chemistry? to write based articles on the internet

What happened here: Adding salt causes water to osmose out of the onion into the pan, which delivers heat to it faster and makes it evaporate away. Only now can onions begin to brown (fact 2), because previously the whole mixture was sitting at the 212 F (fact 1). Adding tomatoes brings the temperature down to 212 F (fact 3) because tomatoes are mostly water (fact 4). The water that’s outside the tomato and onion cell walls eventually steams away, finally allowing the mixture to get hot enough to start browning (fact 2). Browning (Maillard) and caramelization produces yummy flavors, hence the smile.

example 4: chicken stew cooking time

You make a flavorful liquid and begin to cook some chicken in it. The burner is kinda low and the liquid is simmering with quiet determination. Your friend is sitting nearby and the conversation flags. They glance at the stove. You can tell that they’re hungry. But the chicken isn’t fully cooked yet, and you like this friend too much to risk poisoning them with undercooked chicken. You turn up the heat. The liquid begins to boil with abandon. But the chicken still takes a while to cook.

In an alternate universe where you paid more attention in chemistry class, you realize that turning up the heat is futile, a seductive folly. You know what to do instead. You’re prepared for this moment. You’ve been ready for years. You fish the chicken pieces out onto a cutting board and slice each into four or five smaller chunks. You dump them back in. You let the burner stay kinda low and the liquid still simmering. The chicken cooks fast. Your friend gets to eat sooner. You allow yourself a secret smile and continue conversation.

the conversation flags because it’s hard to simultaneously maintain moisture awareness and pay attention to what humans are saying

What happened: turning the burner up won’t change the temperature of the simmering liquid, because that simmering liquid is already at the boiling point of water (fact 1). The boiling will become more vigorous, but that simply changes that speed at which water is evaporating, not the temperature. So turning the heat up won’t cook chicken any more quickly. For chicken to cook, it must reach a certain temperature (165 F according to the FDA but their incentives are to publish overly-conservative numbers since they must consider the young, the elderly and the immunocompromised, and they don’t care about how yummy the food is). The last part of a piece of chicken that will get to that temperature is the center. Chicken conducts heat way less quickly than water (fact 5), so cutting it into smaller chunks allows hot, thermally conductive water to get closer to the centers of those chunks. This makes the chicken cook faster.

do you actually need to think this hard about cooking?

Clearly no, since most people making Indian food aren’t thinking about physical chemistry concepts. But I find it really useful as an alternative to memorizing a bunch of rules, or directions in recipes that ask to add a “cup” of water, as if that doesn’t depend greatly on factors like humidity and how wide my saucepan is.

Unfortunately I haven’t yet developed a series of practical exercises for developing moisture awareness, so all I can offer are the words in this post. Sorry!