For as long as I’ve known how to make grilled cheese I’ve been a butter partisan in the cooking oil wars. I’ll add a dab to stir fry, a dollop to vegetables, and drench my pasta in its glistening broth. I knew it was like, dried cream or something, but I’d never really thought about what butter is until I read Elaine Khosrova’s new book Butter: A Rich History. It turns out there’s a lot more to this spreadable milk fat than I’d ever imagined.

Billed as part travelogue, part history, part dairy science, and part cookbook, Butter is an exploration of one of our most common foods that’s both journalistically rigorous and totally digestible. I can’t stop telling people about the things I learned from it. Did you know that some dairy farms briefly employed dogs to power butter churns? Or that butter sculptures are central to Tibetan Buddhism? Or that ancient Romans derisively referred to Germanic peoples as “butter eaters”? Well, I had no idea.

To find out more about this deceptively satiating comestible, I spoke with Khosrova over the phone. She told me about butter’s rancid beginnings, her favorite varieties, and why it’s so hard to find a good croissant in America.

Extra Crispy: Why did you decide to write a book about butter?
Elaine Khosrova: I have spent my life being a food writer. For a good chunk of that I was editor of a magazine all about cheese, so I had the opportunity to understand things in the dairy world not just from a taste perspective but also how things are produced and what affects flavor. Traveling around the world I tried different butters and different styles, like higher fat butters, whey butters, cultured butters. I was really astonished by the fact that butter is made from one ingredient—cream—yet all of these butters taken together had many different nuances in their texture, color, and flavor. So I really wanted to understand how it’s possible that one butter is tangy and almost coarse in texture and another butter is sweeter and cohesive. I just kept finding fascinating facts about butter’s history that actually had little to do with production—they were much more cultural stories about butter. I actually went looking for a book on butter and there was no book on butter, so that really clinched it.

I was surprised to learn from your book that butter was probably invented accidentally.
Yeah, I think that’s probably true about a lot of basic food products. We’ll never really know for sure because this is way before recorded history, at least 9,000 years ago. We can imagine that a shepherd had a container of milk, probably held in an animal skin, and in that skin it would have fermented slightly. It would have been a shepherd that had goats or sheep because at that point cows had not yet been domesticated. We can imagine if that milk just traveled over land for half an hour, that rocking, whether on the back of a shepherd or the back of an animal, that was essentially churning. This probably happened in multiple places around the world.

How would the butter that people ate for thousands of years have compared to what we have now?
The modern butters that we have are really quite different. For one thing, there was really no such thing as sweet cream. People probably think that’s a nice branding term, but actually that harkens back to the early 1900s when the cream separator was first invented. This really revolutionized the dairy world. Up until that time, if you wanted to collect cream for butter making, you poured the milk into troughs and had to let it sit for 18 hours. During that time the cream rises to the top of the milk. Then you’d skim off the milk and make butter. With the invention of the cream separator you could put the milk through this machine and separate the liquid and fat portion. Suddenly you had really fresh sweet cream. It wasn’t the kind that sat out for 18 hours, during which time it would have got a little tangy, a little more acidic. Some foodies are discovering cultured butter and like a little tanginess but the early butters would have been really sharp tasting, really funky. We would have not liked them really much at all.

You describe a lot of this pre-industrialization butter as “rancid.” Does that mean it would make people sick, or just that it’d taste bad?
The rancidity definitely won’t hurt you. You’ll just gag. We gag on it because we’re not used to it. Think about the way some of us like a really strong blue cheese. If you were to go to a place like Nepal where they’re totally accustomed to rancid butter but not blue cheese, they would taste our cheese and be like, “ugh.” It’s definitely a cultural thing. The issue with getting sick on milk or butter, that’s a different class of bacteria. There are butters they’ve pulled out of the bog that are hundreds of years old that people have tasted and not gotten sick. When people get sick, it’s not like they taste anything in particular; there’s really no simple correlation between “oh, this is getting funky” and “oh, I’m going to get sick.” Getting sick usually isn’t a problem with butter; it’s more a question of offending tastes.

There’s a quote in the book that compares butter to wine in terms of having a terroir. What kind of things affect the flavor of butter?
There’s essentially three living dynamic things that determine the quality of any butter: man, land, and beast. The land supplies the fodder for the animal, whether it’s grass, grain, wheat, or flowers, and these things definitely affect the taste and color of butter. The animal—cow, goat, sheep, water buffalo—each of them produce different kinds of butter. Even comparing a Jersey cow to a Holstein, their milk fat is not identical. You can have nuances in texture, color, and flavor based on the breed. Finally, there’s man. Being the butter maker, they can choose to do certain things or not do certain things. For instance, if they culture it and create more tanginess, that’s going to change the quality of the butter. If you overwork a butter you can make it a little greasy, if you don’t work it enough it can be not as cohesive.

What kind of butter do you use? Should I be spending more money on fancy artisanal butter?
That’s mostly subjective. We should be very grateful for the fact that we have simple, good, affordable butters. We can be sure our cookies are going to come out the same every time because they’re so standardized. At the same time, it’s wonderful that we’re turning the clock back and discovering more artisanal butters. When I was growing up in the ‘60s, there were basically two kinds of butter on the shelves and they tasted identical. They were probably made in the same plant. It’s very cool that we have butters that we can rely on and at the same time we can discover old world-style butters and imported butters, higher fat butters, even whey butters. I just think this has never really happened before in history. Personally, if there’s a butter I haven’t tried I get it. I do buy a grass-fed butter for my table butter. I really feel like I know it’s more nutritious and when I’m having a little bit of butter every day, those micronutrients really add up. I treat myself to that. It’s a little bit more money but it’s such an affordable luxury in the scheme of things. If I’m baking, I generally use the more all-purpose butters. If I’m making croissants I’ll splurge and get a higher fat butter because that definitely makes them turn out butter.

There are many good butters out there. Honestly the butters that I haven’t enjoyed are typically small, artisanal ones where maybe they aren’t quite sure about production. I think those are a little more chancy, although I’ve had great ones too. There’s no guarantee that just because it’s small-batch it’s going to be a fabulous butter. You’ve got to try it.

Speaking of croissants, why is it so hard to find a good one in most of America?
Much of the processed bakery world doesn’t use butter. They use cheaper vegetable oils, spreads, and hydrogenated fats. I think most Americans have forgotten what a real croissant tasted like, if they ever knew. You couldn’t get away with that in France.

In addition to sampling lots of different cow butters, you tasted butter made from goat, sheep, yak, and water buffalo. How’d they compare?
Goat butter and sheep butter are really quite different from cow’s milk butter. Goat butter is definitely becoming more available and I do encourage people to try it. There’s a couple brands from England called St. Helen’s and another called Delamere that are really nicely done. They’re very nice. But not everyone likes them; I’ve had some tastings where people are like, “No, I’m tasting goat and I’m reminding myself of little baby goat kids.”

Sheep butter is a really tricky butter to make. It’s hard to find. There is a very good producer in California called Haverton Hill. It can be very greasy and quite gamey, but I find Haverton Hill’s is really nice. It certainly has more of an animal taste than cow’s milk butter.

As far as yak butter, in the Himalayas it has the reputation of being a really funky, rancid butter. That was not my experience because I actually hiked up to 13,000 feet where I could stay among the yak herders and actually taste fresh yak’s milk butter, which was honestly kind of disappointing. It was very mild. It wasn’t even as sweet as cow’s milk butter.

The water buffalo butter that I had in India was one of the best butters I’ve ever tasted. It was a little bit tangy but deeply flavorful. Absolutely delicious.

Until I read your book I had no idea that, before industrialization, butter was primarily made by women.
The whole dairy industry really grew up on the shoulders of women around the world. For thousands of years, it was taboo for men to have anything to do with handling milk. That kind of work was so closely identified with the female rites of lactation and birthing and fertility. When I went to Bhutan and India, the women were still milking the yaks and water buffalo. That’s how it was for a really long time. On the one hand you can say, well, it was another chore that women had to do. But that chore gave them a certain status in the community, partly because men didn’t really understand. Butter making was pretty mysterious; you have this white liquid and you agitate it and suddenly these golden morsels appear. It was pretty magical, before the days of science when we figured out what was happening. If you didn’t know what you were doing, if you didn’t have the right temperature or let it culture a bit, it wouldn’t turn into butter. It’s not a guarantee. When the cream separator came along, that really shifted everything. Suddenly it made sense for farms to simply sell their milk to a central creamery that had cream separators. At the creamery they employed people to run the churns. Initially they would hire women but as the batches got bigger, they had to employ men—it just became a question of muscle power. So within a generation, by the early 1900s, women suddenly lost their monopoly on the dairy arts, at least in developed countries. It’s kind of bittersweet; there was this whole cultural infrastructure around women selling their butter and that was lost, too.