Not to be confused with yogurt, and yes, they're different, as I learned right before I wrote this blog post. So, anyway, most Indians - or people from the subcontinent - consume some form of curd (or Dahi, as it's called in northern India) either as it is or used to make things like curd rice or chutneys or marinades, etc. I certainly loved it as a kid (still do), and as I've grown older, I've realised not many in my generation really know how to make it. It's available commercially, though, so maybe that's why the incentive to learn is a little less. However, I'd argue it's a nice thing to know, especially if your household is anything like mine and you chug through a litre of Dahi in a couple of days. It's not the most complex item to make anyway, and all you need is some milk, a container, some curd from before, and the most important thing - some time for the curd to set. I need a marinade of some kind every other week for my cooking, so it's good to know I always have it in the fridge if I need it.
It really is simple, and I'd encourage you to try making it at least once and then judging. The provided measurements are what I use, and honestly, the best piece of advice I can give you is that when you've made your first batch, you may find that your taste buds aren't quite the same as mine, so feel free to experiment around with the ratios until you find what works best for you.
What you need
So, what you'll need is about 1 litre of full-fat milk. Full fat milk works better than low fat, but I've used both in the past. If you prefer avoiding the extra fat, then, by all means, go for the low-fat option. Just remember that the time it takes to boil will change ever so slightly. Boil this milk. If you wish to do this on a stove, that's completely fine; I use my microwave oven for approximately 8 minutes (or until it starts boiling).
While it's boiling, I take a container and line the container's bottom with some curd that I already have at home. This is approximately 1 tbsp and a bit of curd. If there isn't any at home, using store-bought is fine, all we really need is a starter.
After you've taken the milk off the heat or out of the microwave, let it cool. Unfortunately, I haven't ever checked with a thermometer the temperature at which I transfer the milk into the container. Still, the reference I've been given is that it should be ok for a baby to consume. Usually, this temperature is reached in around 15 minutes or so.
Once I've transferred the milk into the container, the next step is to ensure that the container is kept warm and not moved for the next 6 odd hours. Since I live in a cooler part of the world now, I usually wrap the container with an old tea-towel. Also, I prefer doing this at night, so by the time I've woken up the next morning, the curd would have set.
When it's set, I move the container into the fridge until it's time for me to consume it. Also, the cold allows the curd to firm up a bit more.
I've never treated the art or technique of making curd as an exact science, like baking. It's largely based on trial and error and then finding out what works for you. The simplicity of making curd lies in the fact that there's only 3 variables you have to play around with - the temperature of the milk when you introduce it into the container, how much of curd you use to line the bottom of the container, and if the curd you're using has gone tangy or sour. If it has, it's usually time to start afresh, and if not, it's good to use it as a starter.
Give it a go, let me know if you found it to be as simple as I do, and if you know of any variations, do share it in the comments section.