Like many of us, Mark Schatzker loves steak. But unlike most of us, he loves steak so much that he recently spent three years of his life researching, traveling the world and eating countless ribeyes, tenderloins and t-bones in search of the very best beef known to man. His conclusion? A truly great steak is as wonderful as it is hard to find. Schatzker’s book, Steak: One Man’s Search for the World’s Tastiest Piece of Beef (Penguin, $33), takes him from the feedlots of Texas to the Pampas of Argentina to the famed Wagyu steakhouses of Japan, where he talks to butchers, ranchers, scientists and “beef loyals,” in his hunt for perfection, done medium-rare. We spoke to him about what makes a steak great, as well as where to find one a little closer to home.

How important is marbling in steak?
The reason we think of it so highly is because of effective marketing. It can be meaningful, but it’s often not meaningful at all. I think it was important at one time, but what’s happened since then is that the industry has just gotten extremely good at producing marbled beef very cheaply and very efficiently, using genetically modified corn and hormones and all sorts of things that ramp up production and bring costs down. Marbling basically tells you that a cow has eaten a high-energy diet, but it’s what that diet consists of that’s going to contribute to the flavour.

Does grass-fed beef have better flavour?
My finding about grass-fed was this: the absolute worst steak I ate was grass-fed, and so was the absolute best. It’s much more difficult to do—it’s just very easy to get cattle fat on grain—but when it’s done well it’s just incredibly good.

Terms like Angus and Kobe appear on menus a lot. Are they important?
They can be important, but the problem is the terms are meaningless. A lot of what’s sold as Angus or Kobe beef are at best crossbreeds, which is to say they’re half something else, or sometimes not even half. Breeds in themselves have certain differences in them, but what you buy—what’s marketed as a breed—isn’t necessarily going to reflect that. There’s just a tremendous amount of BS in the beef world, as you can tell.

What about ageing? Does more ageing translate to better steak?
I think there’s something valid to ageing, but there’s a lot of marketing going on. You shouldn’t need to age a steak for 60 days for it to be good. I’ve had steak that was aged for five days that was outstanding. That’s not to say that all steak should be aged for five days, but I think two or three weeks is ideal. Wet ageing is good, too. There are differences, but I think the quality is going to have more to do with the piece of meat that you’re ageing than the ageing itself. You can’t save a lousy piece of meat with ageing.

What’s the best way to go about buying steak?
Here’s the thing: there are no easy answers. If you want to make good steak, it’s hard. It takes a lot of work and it’s not just a matter of organic or grass-fed. It’s a whole bunch of things. I think it’s important to ask if they’ve been using things like hormones or antibiotics. Not to say it has to be organic, but that tells you something about the values of the person raising it. Are they just trying to create something cheap and sell it, or are they trying to create a better product? I think you should ask what age it was when it was slaughtered. Anything earlier than 20 months, you should probably be wary of that. It really helps to know what it ate. That’s probably the most important thing—something that has eaten grass will have a very different flavour profile than something that’s eaten grain.

You say a lot of nice things about tongue in your book. Underrated cut?
It’s a hugely underrated cut. I adore tongue. Especially the way the Japanese do it—thinly sliced and grilled on a very hot flame. It is delicious. A good butcher shop will be able to get it for you, and the best thing to do is get it kind of half-frozen from the freezer, it’s easier to cut that way, and then you kind of cut the skin off it and you’re left with what almost looks like a mini tenderloin, and then you just slice it thinly across the grain and grill it.