Mad About Science: Cheese

By Brenden Bobby
Reader Columnist

Delicious curdled milk has been consumed by humans for at least 10,000 years. Some experts argue that cheese has hidden health benefits, though that probably doesn’t apply once it’s been melted over a slab of burger meat.

We don’t know exactly when cheese was first developed, though we have records of its development from at least 8,000 BCE. Our best speculation is that someone had converted the chambered stomach of a calf into a storage container for milk and left it to sit there for a bit too long. Beyond all logical reasoning, someone decided to eat it and enjoyed the first taste of cheese.

You might be thinking that’s a very vivid and specific example for not knowing a lot about the origins of cheese, and you’d be right. The final chamber of a calf’s stomach contains enzymes that break down the sugars in milk and cause it to curdle. It’s possible that this chambered stomach was used as a long-term storage container or a sort of traveling canteen.

By 100 BCE, cheesemaking had become an artisanal craft, with hundreds of varieties of the foodstuff. Romans especially loved cheese. As they could store it for long periods of time, it was highly portable and mixed with just about anything. The Romans’ love of cheese spread throughout their empire and beyond, becoming an important staple in Europe and the Middle East.

Mmmm, cheese.

Interestingly, cheese wasn’t particularly favored in eastern Asia. Though there is evidence that it had been either independently developed in — or at least the knowledge of its creation had been exported to — China by 1615 BCE, it wasn’t remotely as popular as it was in parts of the Global West.

Cheese didn’t appear in the Americas until European colonization, beginning in the late 15th century. Large, milk-producing animals like cows and sheep were a big part of Europe’s development, but they weren’t native to North America. I don’t know about you, but I have no intention of ever trying to milk a buffalo or alpaca.

Cheesemaking became popular in America by the late 1700s, with New York being the primary cheese producing center. Post-Revolution, Ohio became the next logical step for U.S. settler-colonists to begin producing cheese. The Ohio River allowed for expedient transportation from Pennsylvania all the way to Kentucky, as well as accessibility to the Great Lakes. Ohio and New York were the primary cheese producers on the continent for more than five decades.

In the 1830s, immigrants from Germany, Norway and Switzerland began to settle in Wisconsin by way of the Great Lakes. They brought immense knowledge of cheesemaking with them; and, unbeknownst to the immigrants, would eventually inspire a bunch of people to put cheese on their heads and scream at the TV on Sundays. 

Last year, Wisconsin produced 3.5 billion pounds of cheese, followed by California at around 2.4 billion pounds. Idaho was actually the No. 3-producer of cheese in 2021, producing just more than 1 billion pounds. Idaho only produced 14 million pounds of potatoes last year, so it might be time for a rebranding: “Idaho — Land of Potatoes Au Gratin.”

Enough history, how exactly is cheese made?

One method is to use the enzymes in a calf stomach, as mentioned above, but that’s inefficient, unsanitary and cruel. Instead, we can emulate that process by pouring milk into a vat and adding bacteria to it. There are two specific types of bacteria we add to make cheese, and this type will drastically alter the outcome of the finished product. Mesophilic bacteria like temperatures between 68 and 113 degrees Fahrenheit, and are responsible for milder cheese flavors like cheddar. Thermophilic bacteria like it hotter, between 113F and 252F, and are responsible for cheeses like Parmesan and Romano — you know, stuff with a bite.

These bacteria will cause the sugars in the milk (lactose) to ferment into lactic acid. 

Fun bonus fact: You can actually take the lactic acid, pull the water out of it and create the filament we use in the 3-D printers at the library. The lactic acid causes a reaction of the casein (part of the protein found in milk) molecules in the milk, making them unfold and link together and coagulate until the milk begins to form a funky, rubbery substance called a curd.

If you want your cheese to be harder, you’re going to have to add something called rennet. Rennet possesses the chymosin enzyme from cow stomachs we learned about earlier. This enzyme causes a polarizing reaction in the protein that pushes away water and locks in milk-fat, while also causing a rapid coagulation. This isn’t done in every kind of cheese, but it’s an important step for certain ones like Swiss cheese.

Cheesemakers will take the curd and send it down the line to be pressed. Some cheeses aren’t pressed for long and have uniform slabs sliced from them to create the block cheese you buy at the supermarket. Others are just pressed into a big cheese wheel and left to age for up to 20 years. The aging process further ferments the cheese, enhancing the flavor and breaking down the lactose — the primary reason why people with lactose intolerance don’t have a reaction from aged cheese.

Other cheeses, like cream cheese, generally don’t get pressed and just get packaged and shipped. No one wants a rind on their cheese cake, after all.

Would you believe it? We’ve already reached the end of the article and I haven’t made one cheesy pun. How gouda am I?

Stay curious, 7B.