Let's face it, there are some skills that are just cool to have. Being able to weld things, very cool. Ability to moonwalk? Always cool. And being able to turn everyday milk into wicked good cheese definitely belongs on that list. What if you showed up at your next holiday party with a wedge of queso fresco that—no big deal—you whipped up that morning? Pretty cool.
Some cheeses are more complicated than others. They can require special cultures, special molds (both the shapes they're pressed into and the stuff that grows on the outside), or months and even years of affinage (fancy cheese-speak for aging). Some, however, are very, very easy. How easy? I'll show you, but first I'm going to go all Bill Nye and lay out some basic cheese science, since it's always a little more fun when you know what you're actually doing.
Make That Milk a Cheese
To get started, let's take a minute to talk milk. Milk is made up of proteins, sugars (lactose), fat, minerals, vitamins, and enzymes. All of those things play various roles in cheesemaking, but the real key players in the game are the proteins, namely casein and whey.
Turning milk into cheese is a matter of changing the properties of those proteins, causing the caseins to coagulate into deliciously soft, milky curds and leaving behind the cloudy, watery byproduct known as whey. There are two ways to effect this change: with rennet and with acid, both of which work their magic in combination with heat. Your typical aged, cheese-plate-style cheeses are rennet-set, including cheddar, Parmesan, brie, and the like. But today, we'll be talking about acid-set cheeses. Not only is an acid-set cheese a great way to get your feet wet, but it also happens to be a crazy easy, totally delicious recipe to have in your back pocket.
Acid-set cheeses require nothing more than a pot, some milk, a thermometer, cheesecloth, and an acid source, such as lemon juice or vinegar. When all's said and done, you'll have what's known as queso fresco in Latin America, paneer in India, wagashi in Ghana, and farmer's cheese in many anglophone countries.
But how, you ask, does it all happen? The short answer is that we'll be separating our curds, straining them, and pressing them into a firm, fresh cheese. The long answer boils down to messing with milk proteins.
Normally, caseins and whey are suspended throughout liquid milk. Caseins are basically clumps of protein with amino acid chains sticking out in every direction—picture them as tangled up balls of yarn, with frayed ends dangling all around. In milk's liquid state, these caseins have a slight negative charge, which makes them repel each other (remember the magnets in science class? Opposites attract; like repels like.) Your balls of yarn are scattered across the floor. What a mess! When you, the cheesemaker, lower the pH of fresh milk from 6.7 to 4.6 and heat it to around 165°F, the electric charge of the casein molecules reaches a tipping point. Instead of being repelled from each other, they run headlong into each other's arms and knit tight bonds. Now you've done some housekeeping and you have a whole basket of yarn packed together all cozy-like. (Luckily, that yarn is actually made up of milk proteins, so it also happens to taste really, really good.)
Even better, almost any kind of milk will make cheese, except for ultra-pasteurized. During the ultra-pasteurization process, proteins are damaged in such a way that they won't reliably form curds. You can use raw milk to make cheese, and while it's not always a good idea for rennet-set cheeses (where you won't heat the milk nearly as high as for queso fresco), in this recipe you will heat the milk to the point of pasteurizing it, rendering it totally safe.
How It's Done
So let's actually do this thing! I start by heating milk in a pot, stirring more or less constantly, and watching the temperature on my thermometer. It's easy to scorch the milk at this stage, which will give your cheese an acrid, bitter flavor, so use a heavy-bottomed pot if possible and stir gently and constantly.
When the milk has reached anywhere from 165°F to 185°F, I take it off the heat. Though most recipes will tell you to heat the milk to a higher temperature—between 180°F and 195°F—there's really no good reason to do so. Food safety isn't an issue and extensive testing has shown us that there's virtually no difference in the amount and texture of curd produced within that broader temperature range.
Next, I add my acid. Here, I opted to use lemon juice, but vinegar would also work in its place—it all comes down to the kind of flavor you're looking for. Lemon juice will add a citrusy tang to the cheese, whereas distilled vinegar will leave you with a more neutral flavor.
Working one tablespoon at a time and stirring gently after each addition, I continue pouring in the acid until the curds separate from the whey. It will look like soft, curly white clumps suspended in a clearish liquid, and it will be sudden. Trust me, you'll know when it happens.
Once they've separated, take a break. Let the pot sit uncovered for at least five minutes and up to 20 minutes to complete the separation process.
Now it's draining time! Ladle the curds into a cheesecloth-lined colander. If you don't have cheesecloth, you can also use a clean sackcloth dishtowel. The finer weave means the draining will take a few minutes longer, but the cloth is reusable and ultimately cheaper if you plan to make cheese frequently.
If you want to save the whey, place the colander over a large bowl. I like to use it for marinating or braising meats—the enzymes in the whey have an almost magical tenderizing effect on meats and add a nice depth of flavor. For those same reasons, it's also good for soaking grains. It can even be used in place of water for bread recipes. Some people even feed it to their pets, but I've found my dog can only stomach it in small doses (although she goes crazy for it and would drink as much as I let her).
If you're just in this for the cheese, though, you can drain your curds over the sink. Either way, allow the curds to strain for a good 20 minutes for pressed cheese, or a full hour for fresh curds (though not true ricotta, those fresh curds are in fact what most of us know as ricotta these days). To salt the cheese, sprinkle a quarter teaspoon of salt over the curds and gently stir it in.
For pressed cheese, gather the curds into a ball in the middle of your cheesecloth and press them into a hockey-puck shape.
Then, tie the cloth around the cheese, place bound cheese back into the colander, and put some kind of weight on top—I like to use a small plate weighed down by a large mason jar of water, but several cans of food would work, or really anything that weighs a few pounds.
Let your set-up rest for an hour and a half, or until the cheese has reached your preferred texture—the longer you wait, the firmer it will get. It'll keep for up to a week in the refrigerator, but it's best used right away. There you have it—everything you need to know (okay, and maybe a tiny bit more) to make a basic cheese. Super cool.
So What is it Good For?
How firm you make your cheese depends on what you want to use it for. Unpressed, it's great for crumbling over soups and salads. But if you're going for slices or cubes you'll need to press it. It's just as tasty either way, but pressed acid-set cheeses like paneer and queso fresco are unique because they won't age and they won't melt. This makes them great for grilling (or just for eating right away). You can use them in simple stir-fries and easy butter paneer with spinach, or grill them for sandwiches and tacos. The possibilities are vast and pretty uniformly delicious. So what are you waiting for?