An Ode to Dahi

I stood in my kitchen, glaring at the bowl in my hand. It had been in the oven with the light turned on all night long and then some, just as the instructions online specified. Yet for some reason the milk inside the bowl—with a spoonful of Danone yogurt from Tesco stirred in—remained liquid. Lukewarm, but liquid. Offensively liquid.

It was my third attempt since moving to London at making dahi, or Indian yogurt, and I was just about ready to give up.

I hadn't expected to care about making dahi while setting up a new life on the other side of the world, despite the fact that Marathi people are notorious for putting gigantic helpings of it on and in practically everything. (Dahi on misal, anyone? Or on chivda? Exquisite.) I had found it perplexing when I'd heard that new immigrants went to extraordinary lengths to remake dahi abroad—smuggling starter cultures from India in their luggage, trekking to faraway Indian grocery stores, posting messages on expat forums agonizing over why they simply couldn't get the yogurt to set. Why go to all this trouble, I used to wonder, invoking that ubiquitous Marathi phrase used to dismiss anything even remotely frivolous: "Ugich kashala?" Why unnecessarily?

But in September 2021, when I moved from hot, humid Mumbai to cold, humid London, I found myself struggling with the same unnecessary predicament. As the first leaves turned orange and red outside my window, I decided I'd try making dahi—a process I'd perfected during 2020's lockdown over many long, restless afternoons. I'd tell myself—and my roommates—that it was just a "weird" culinary experiment when in fact I was attempting to recreate a well-honed ritual and the sense of calm that it had once brought me.

Except now, it was maddening. I seemed to be doing everything right—boiling and cooling down the milk to the right temperature, adding the right amount of starter, letting it rest the required number of hours. And yet, my dahi wouldn't set.

Generations of diaspora Indians will relate. When Devika Rao moved to California from Hyderabad nearly a decade ago, she, too, found herself battling the unexpected challenge of making dahi in a new country with a drastically different climate. "I would usually give up after a day or two of trying," she recalls. "Most of my attempts either took too long because of the difference in weather...or the resulting dahi would be too stringy [or] slimy or not taste good."

In 2006 New York, then-26-year-old Gaurav Sabnis, on a tight student budget, had faced a similar conundrum. "I noticed that chicken drumsticks were surprisingly cheap in US supermarkets," Sabnis, now a professor at a New Jersey university, writes over email. "So I thought a great way to make a cheap, tasty, easy home-cooked meal as a grad student was to buy those cheap drumsticks, marinate them in yogurt and spices in the morning before I went to the university, and then put them in the oven in the evening."

Sabnis then realized he could save even more money by making yogurt at home. Having grown up in a household where dahi was a mealtime staple, he figured that making it for the yogurt marinade would be a breeze.

He used a bit of leftover yogurt from his Danone tin as a starter and followed the process he remembered—boiling the milk, then letting it cool down to lukewarm, followed by stirring in the starter and leaving it to set overnight.

The next morning, the milk looked unchanged, the dahi had not set. Sabnis left it for another day, but returned to find the milk still entirely liquid. Calls to his mum back home and following her detailed instructions didn't help. The yogurt refused to set. "I was baffled," he says.

In California, Nishaanth attempted to add chilli pepper stems—which are supposed to be rich in lactobacilli, the microorganisms responsible for transforming milk into yogurt—to the milk in lieu of a good starter. My friend Christina had searched high and low for dahi while living in Beijing. Swati (name changed on request) in Boston tried keeping the milk inside a cupboard for warmth, then near her radiator, but to no avail. "It ended up too sour," she tells me. "I should have just tried bringing a bit of the starter [culture] in my luggage after my last India trip. But I was afraid it would spoil."

It shouldn't be this difficult, in theory. The process of making yogurt in general is pretty straightforward. Heat up whole milk until boiling or near-boiling temperature, let it cool down to lukewarm, mix in the starter culture and then let it "set" in a warm environment for 10-12 hours, a little longer if the weather is cooler. And dahi is yogurt, after all, even though it's different from much of the yogurt I've found in grocery stores in my new home.

I feel like a Bad Indian every time I attempt to explain what dahi is to my non-South Asian friends. I find myself explaining it in terms of what it isn't instead of what it is. "It's not aggressively sweet like some American yogurt," I might say. "And it's not strained, so it's not as thick as Greek yogurt."

Or I end up making it sound rather weird.

"It's kinda...liquidy? Or crumbly but, like, in a soft way?"

"Yes, it's pretty sour. But not too sour?"

And, honestly, dahi deserves a better publicist. Because when made right, it's a work of art, with a texture that's softer than caramel custard. A freshly made bowl of dahi has a smooth top that immediately yields once you sink a spoon into it. You can eat it by itself or put it in a kachumber salad with lots of green chiles, turn it into a dip, or add it to marinades and curries. The popular street snack dahi vada—deep-fried rings of fermented lentil batter dunked in dahi and topped with spicy and sweet chutneys—was first recorded in the Sutra literature from 500 BC, according to veteran food historian KT Achaya. And dahi mixed with steamed rice—known as dahi bhaat, or "curd rice"—is a comforting staple for several Indian communities, one that's mentioned in the ancient Rigveda (1500–1000 BC) texts, writes Achaya in his landmark book, Indian Food: A Historical Companion.

Oddly, the term "curd" may be a bit of a misnomer. In India, "yogurt" and "curd" are used synonymously as the English translations for dahi, though the latter technically only refers to milk from which the whey has been removed, explains food historian Ken Albala, an expert on fermentation.

"Only in India does the term 'curds' also refer to yogurt, which I’m pretty sure is an accidental Anglicism—applying a familiar English term to something totally different because they had not yet begun to use the word yogurt (which comes directly from Turkish)," writes Albala over email. "It really only became popular in the West in the wake of health promoters like Elie Metchnikoff identi[fying] lactobacillus cultures and claim[ing] that they were good for promoting 'intestinal flora' or, as we would now say, the gut microbiome."

The primary distinction between dahi and other kinds of yogurt is the different bacterial strains used in the starter culture. While the process of making yogurt is essentially the same across the board, there are specific conditions that work best for the strains that produce dahi, conditions that become ridiculously complicated to recreate the minute you leave the Indian subcontinent. The temperature of the environment, the proportion of the starter to the milk, the temperature of the milk, the number of hours it must sit in order to "set"—all of these very finicky conditions must be met or else the dahi will be too khatta (sour) or lumpy or watery or yellow.

"It is a tricky process," says Krishnendu Ray, Professor of Food Studies at NYU. "Most people...simmer their milk for 15-20 minutes to half an hour and then cool it down, without cooling it down too much. The milk should be slightly warm to the touch—how warm is of course a qualitative judgment."

Making dahi, says Ray, involves a "very subtle balance between the nature of the starter, how warm the milk is, and then, where you keep it to set, even the microbes from your skin and in the air."  Sometimes it'll end up too sour, or not sour enough, or with a surface that's slimy and wet, instead of the smooth, still, spotless top that is the mark of Good Dahi.

While interviewing Bengali immigrants to the US for his 2004 book, The Migrant's Table: Meals and Memories in Bengali-American Households, Ray recalls that making dahi at home was a near-unanimous point of pride.

"Because it was a little challenging to start off and not too easily done—that is why people put value to it," he says. It was a way—albeit a largely gendered one—of taking care of the family and making the new country feel more like home.

The process of dahi-making also fostered a sense of community. Starter cultures were freely shared, as were ingenious tips and tricks for producing good dahi—swaddling the bowl with a blanket to keep it warm in a colder climate, or adding chile stems. Every household had a patented method guaranteed to produce the freshest, sleekest batch of dahi you ever saw.

As I learned, so did my mum. "Forty times clockwise and forty counter-clockwise," she'd admonish, when I tried to rush through it. That was the mandated number of times the warm milk was to be slowly stirred after adding a spoonful of the starter—either from a previous batch, or a tin of Amul dahi.

Mum had also taught Baba to make dahi a few years after they married. He is now the household dahi setter most nights, rigorously following the Sacred Texts: bringing the vessel of cow's milk—delivered by the milkman in plastic packets each morning—to a full boil, pouring it out into the designated glass bowl and letting it cool down to lukewarm, and then adding the starter, stirred in 40 times clockwise, 40 times counter-clockwise. The second it sets, he ladles some out for himself, topped with a heaping spoonful of sugar—his favorite dessert in the world.

I don't remember the exact day I decided to learn how to make my own dahi but I do know it was long enough into lockdown 2020 to have gotten sick of all the elaborate cooking projects of the first few weeks. I had thought for so long that making dahi was simple and uncreative and boring. But then I came to love the stillness of the process, which demanded my complete attention, and helped my anxious mind slow down. It was almost meditative, paying careful attention to heating the milk and mixing in the starter, and then completely backing off and the waiting until the dahi set just right. I'm not a patient person by any means, but there was no rushing dahi.

Several people I spoke to now use the yogurt setting on Instant Pots to make dahi, though it also does require some trial and error. "The first batch usually comes out a bit on the thinner side, but using this as a starter for the next batch will strengthen the culture and the third or fourth batch onwards, [it turns out] much better," says Arjun D Law, a hematologist based in Ontario.

If you set your new batch of dahi using a starter from the previous one, you could technically keep that one starter culture going for decades, says Albala. "It can live forever." All you need is that one good starter—either from a batch you have made using store-bought yogurt (including the ones from Indian shops abroad), or better still, using someone else's homemade dahi.

The dahi I finally, finally made in London this autumn was born of one such starter, couriered to me by a wonderful lady I found on an Indian expats forum. It arrived in a double-sealed Ziplock bag with detailed instructions sent to me over Facebook messenger. It reminded me of the sense of community generated by discussions about the difficulties of making dahi that Ray had encountered in his interviews.

I mixed the starter into my boiled-and-cooled Tesco whole milk, covered the bowl, and kept it all night in the oven with the light switched on. In the morning, when I took the bowl out and peered in, I almost thought the dahi had not set well, and my heart sank—the top layer wasn't as smooth as I remembered it being back in India, and it looked crumblier than it should be. But then I dug a spoon in and it immediately yielded bright white and soft dahi underneath, with the familiar sour-sweet taste, exactly like the dahi from home. I'd done it. And thanks to the new starter, with each subsequent iteration, it'd only get better. I was thrilled.

Dahi was, in theory, probably the dumbest, most useless thing I could have tried to recreate here—thousands of miles away, involving a truly ridiculous amount of effort and a lack of pretty much all of the things I needed to make it. And yet, somehow, it has brought me such pure joy because of all of the things that needed to be exactly right for it to turn out this way. For the few minutes I'm making dahi each day, I remember to slow down and focus only on what's in front of me. No dumb worries about the future, no pointless ruminating on the past—just me having a go at making a damn good bowl of dahi.