Sweet Lassi

Why must the curd be fresh rather than sour?

Because souring is one way and sugar cannot reverse it. Curd continues to acidify as its cultures work, and once it has tipped past pleasantly tangy the lactic acid dominates everything else, so you end up chasing it with more and more sugar and getting a cloying drink that still tastes sharp underneath. Curd set that morning, or the day before and refrigerated promptly, is what you want. Sour curd is not wasted; it is the correct choice for kadhi, dhokla batter and marinades.

How do you get lassi genuinely thick?

By using set curd rather than pouring yoghurt, and by adding liquid slowly enough to control it. Start from curd thick enough to hold the shape of a spoon, whisk it smooth on its own before anything else goes in, then let the water down in stages. Once a lassi is too thin there is no fixing it without more curd. Hung curd, drained in muslin for an hour, gives the very thick Punjabi style that has to be eaten with a spoon.

What does churning actually do?

It builds foam by working air into the protein network, and that foam is most of the difference between lassi and a glass of sweetened curd. The traditional mathani, spun between the palms, does it by shearing the mixture rather than cutting it, which is why hand churned lassi holds its head longer. A blender run fast warms the drink and tears the proteins, which makes it thin and slightly grainy. Use the lowest speed and short bursts, or a whisk and a minute of effort.

Is a glass of lassi healthy?

The base is, the sugar usually is not. Curd brings protein, calcium and live cultures, which is why lassi is a far better proposition than most cold drinks sold beside it. What varies enormously is the sweetening: a shop glass can carry four or five teaspoons plus a float of cream, and at that point it is a dessert in a glass. Making it at home lets you halve the sugar and taste the curd, which is also how it is drunk across most of Punjab. The gut health course goes into what live cultures do and do not do, and the piece on curd against commercial yoghurt covers the labelling differences worth knowing.

Should it be made with water or milk?

Water is traditional and makes a lighter, more refreshing drink that still tastes clearly of curd. Milk gives a richer, rounder result closer to a milkshake and blunts the tang, which some people prefer and others find flat. Neither is wrong. What does matter is that both should be properly cold, since a lassi made with room temperature liquid needs ice to rescue it, and melting ice waters it down while you drink.

What else can go in?

Rose water is the common Punjabi flourish, a few drops only, added at the end so the heat of churning does not drive it off. Saffron steeped in a spoon of warm milk gives colour and a different perfume. Ground cardamom is near universal. For the salted version you drop the sugar entirely and add roasted cumin and black salt, which is closer to masala chaas. Fruit turns it into something else again, the most popular being mango lassi.

Why add salt to a sweet drink?

A small pinch makes the sweetness read as more rounded and keeps the lactic tang from sitting flat. It works the same way salt does in a caramel or a fruit sorbet, by sharpening contrast rather than by being tasted itself. Use enough to notice a difference and not enough to identify, roughly what fits under a fingernail for two glasses. If you can taste salt, you have gone too far.