What's the Deal with... Tyrosine and Calcium Lactates

Alex Van Buren
Food Features Editor

You know that thing? That thing that sounds like something you should already know about, so you don’t really want to ask? Well, we know about it, and we’ll give you the intel. Welcome to What’s the Deal With.

Roomano (yes, roomano) cheese, which contains calcium lactate crystals. Credit: Murray’s Cheese.

Have you ever noticed something a little different about certain aged cheeses? Are those crystals in your Gouda or something crunchy in your English cheddar? What IS that? 

That thing goes by the “Game of Thrones”–like name of “tyrosine,” or the more nerdy-sounding “calcium lactates.” We hopped on a call with Dr. Scott A. Rankin, Professor and Chair of the Food Science Department at the University of Wisconsin-Madison (a state in which, of course, they know their fromage)so he could clarify what the heck those crystals are.

What It Is: Cheese is “a complex food” in many ways, said Rankin, and as it ages “compounds [such as tyrosine and calcium lactates] are formed that aren’t very soluble.” Parmigiano-Reggiano, which loses much of its moisture in the aging process, is a great example of a solution that has lost “much of its moisture to the atmosphere” and therefore may well contain such compounds (in lay terms: those crunchy, crystallized bits).

Tyrosine (often found in aged Goudas), an amino acid first identified in 1846 by a German scientist, is produced by whey latching onto proteins in the cheese-making process. Calcium lactates (often found in aged cheddars) are produced by the milk sugar, lactose.

Distinguishing Characteristic: Both tyrosine and calcium lactates produce crystals, and it’s their textural crunchiness you notice mid-bite of a harder cheese. Note that sometimes you’re tasting crystals, and sometimes not: We initially thought they were responsible for the texture of the excellent Pleasant Ridge Reserve, from Dodgeville, Wisconsin, but Rankin set us straight: “You could have people swear up and down” that they had identified calcium lactate or tyrosine in a cheese, he says, but it’s “complicated,” even for a scientist. Pleasant Ridge’s raw cow’s-milk cheese is sweet and dense, but Rankin says there are “not a lot of crystals” in that cheese, and they’re “pretty small when I see them.”

Why It’s Popular: Aged cheddars, Goudas, and even some Swiss cheeses have tyrosine and calcium lactates (and sometimes both!), said Rankin. These are styles that have never gone out of favor with Americans. 

How to Know Which is Which: You can’t. But most of the time you’re looking at calcium lactate, not tyrosine, which is rarer. “Most likely aged cheddars have lactate crystals” and “most of what you’d encounter in cheeses is calcium lactate,” says Rankin, so you can’t drop “tyrosine” at cocktail parties with the ease you might like. And unless you have access to some dairy scientists and a lab, you’re out of luck in knowing for sure.  

Where to Get Them: Any smart cheesemonger is going to know what you’re talking about when you start asking about calcium lactates, tyrosine, aged Goudas and aged cheddars. Taste your way through them, enjoy the crunch and their beauty—look at those crystals!—and know that sometimes (bummer) a crunchy bit is just dried whey, which sounds much less foxy but is still delicious.