Why Every Rajasthani Kitchen Makes Chach in Summer

In most of India chach is a beverage. In western Rajasthan it is closer to a staple - something made in quantity every morning in summer and finished by afternoon, drunk by anyone who has been outside and offered to anyone who arrives.

What it actually is

Chach is what is left when dahi is churned and thinned with water. It is lighter than lassi, more sour, and almost always salted rather than sweetened. The proportion of water is not fixed; every house has its own, and people are quietly firm about theirs being correct.

Why it took hold here and not everywhere

The practical answer is that it is mostly water, it is cold, it is salted, and it is made from something that was already in the house. In a region where the summer runs long and the work is outdoors, a salted cold drink made from the morning's milk is a sensible thing to have a jug of. It did not need to be invented so much as arrived at.

It also solves a problem at the other end. A dairy household has more milk in summer than it can drink and no good way to store it, and turning it into dahi and then chach is the oldest answer to that. The tradition and the logistics are the same thing.

How it is usually seasoned

Salt, always. Beyond that it varies: roasted jeera, a little black salt, sometimes green chilli or curry leaves, occasionally nothing else at all. There is no correct version, though you will meet people who disagree.

Drinking it the same day

Chach does not keep. It sours quickly, and unlike dahi it does not become useful as it goes - sour dahi has a job in kadhi, sour chach has none. Make what will be drunk, and drink what was made.

We churn ours from the dahi set that morning and send it out on the same round, for the same reason every house here does: it is not worth drinking the next day.