Milk. The fluid that nourishes all mammals through infancy, and defines our position in the animal kingdom. It is packed full of nutrients, and is an essential part of a healthy diet. The 90s have really driven home the nutritious benefit of the glass of milk, from the super-catchy Amul ad jingle to that unforgettable hit by one of my all-time favourite Bengali bands that goes “Doodh na khele hobe na bhalo chhele”.

The most commonly consumed milk is obtained from the cow or buffalo, although goats and sheep also provide milk for consumption. Yak milk is commonly consumed in Tibet, camel milk in the Middle East and of course, reindeer milk in the Arctic North. While unpasteurised or raw milk has its audience, with some suggesting that the bacteria naturally present in milk act as a probiotic, it is more common to pasteurize milk before consumption. It is a technique developed by the French microbiologist Louis Pasteur and has been adopted by milk industries worldwide.

All milks, irrespective of source, are emulsions, meaning they contain fat dispersed in a water medium. If these fat globules are too big, they might clump up and ruin the texture. This is prevented by a process called homogenization, which involves pushing the milk through a tiny orifice such that the fat breaks down into tiny microglobules that cannot clump together anymore. On the other hand, add lemon juice or rennet to milk and the emulsion is broken; the solids clump up leaving behind the liquid or the whey. These curds are the beginnings of cheese, but that will have to wait for its own article.

And speaking of spoiled milk products, there’s yoghurt. Although pasteurization kills off naturally present bacteria, it allows for the addition of other critters into the mix, most commonly lactobacillus, which ferments the milk to produce yoghurt. Yoghurt can be eaten as it is, mixed up with granola, used an ingredient in curries or made into a refreshing lassi or chaas. Chaas is similar to a Bangladeshi burhani, and both tend to be salted and more watery compared to a thicker, creamier lassi.

Put milk into a centrifuge, and you can separate the water and fat contents. The cream floats to the top and can be removed, with the residual liquid containing a markedly less fat content. This is skim milk, which has zero percent fat. In contrast, whole milk contains around 3.5 percent fat, while partial skimming produces low fat varieties like 1 percent or 2 percent milk. Dehydrate skim milk and you get milk powder, rich in protein. Toned milk on the other hand involves the addition of water and milk powder to whole milk, which produces a milk with a lower fat and a higher protein content. Toned milk is in fact, an Indian concept. Both skimmed and toned milk are usually considered to be healthier owing to the low fat and calorie content, although differences in opinion abound.

While pasteurization, homogenization and toning are essentially industrial processes, evaporated milk can be easily made at home, though ready to use cans are available in the West. All it involves is boiling off some of the water (around 60 percent) to produce a richer milk with more body. Sweetened condensed milk takes this a few steps further, reducing the milk to a syrupy consistency along with the addition of additional sugar to create a concoction more akin to dessert than beverage. Continue the reducing process and you end up with khoya or milk solids, used in a lot of Indian sweets like the North Indian kalakand and Parsi mawa cake.

Skimmed and toned milk are the worst possible choices for desserts. When making a kheer or rabdi, the last thing you want is skimmed milk, because the low fat content will never give you the desired mouthfeel. Evaporated milk, with its richer body, is ideal for desserts like rasmalai or our very own doodh puli, although you could easily use whole milk or full-fat milk (just stay away from the skimmed stuff). Check out more about milk-based Bengali sweets in our Mishti series from last pujo.

Milk, especially in the absence of a richer cousin like cream or mascarpone, plays less of a dominant role in Western desserts, however there are exceptions The Latin American tres leches cake literally translates to “three milks” and employs soaking a cake with a mixture of evaporated milk, sweetened condensed milk, and half-and-half. I’ve had an intersting Indo-Latin Rasmalai tres leche at Farzi Cafe a couple of years back, and it was wonderful.

Which brings us to the cream we had skimmed off the top while making skimmed milk. It contains most of the milk fat, also referred to as butterfat. In the West, creams are categorized based on the percentage of butterfat it contains. Half-and-half contains around 12 percent, light cream around 20 percent while heavy cream contains about 38 to 40 percent butterfat. The higher the fat content, the more easily it holds on to air and the more readily it whips up into a foam. Depending on how rich you want your ice-cream to be, you can choose anything from skim milk to heavy cream, but don’t go as far as double cream, because churning that will produce butter, which we’ve talked about at length in a previous article.

Let’s circle back to milk, and contemplate some of its applications in the savoury kitchen. Sure, it makes a healthy beverage and forms the basis for countless desserts, but milk plays a vital role in savoury dishes too. In the West, one of the best-known savoury applications of milk is the béchamel sauce, one of the five French mother sauces (more on those some other time). Béchamel sauce is basically milk thickened with a roux (a flour-butter mix) and flavoured with ingredients like pepper and nutmeg. It is used in layering up lasagnas in Italy, and making bite-sized croquettes mixed with ham in Spain. Add cheese to a béchamel and you get a sauce Mornay, the basis for the classic mac and cheese.

Stewing foods in a milk-based sauce is common back home, an excellent example being the simple yet delicious doodh potol. Although yoghurt and cream are much more commonly used in curries as compared to milk as it is, cooking with milk lends its uniqueness to the dish. Cook milk for too long and it will curdle, and as unappetizing it sounds, the tender curds provide an amazing texture and is the USP of the traditional Italian dish maiale al latte or pork braised in milk we talked about in our Slow Cook series last winter.

Milk is so much more than a healthy beverage. It forms the basis for numerous dishes from Mac and cheese to kalakand. Milk derivatives like butter, cheese, cream and yoghurt have their own unique applications in the kitchen. No wonder those 90s folk went on and on about this magical elixir of life.