Celebrating National Moldy Cheese Day might raise an eyebrow or two. But that is okay because it’s worth noting that “moldy” cheeses like blue cheeses (e.g., Roquefort, Gorgonzola) get their veining from a mold like Penicillium roqueforti that is deliberately added to the milk or curds.
The cheese is later pierced with needles to allow air inside, which is what the mold needs to grow and create its signature blue color and tangy flavor. For soft, bloomy-rind cheeses (e.g., Brie, Camembert), a surface mold like Penicillium camemberti is responsible for the edible white rind and creamy texture.
How Is Cheese Made?
The Four Essential Ingredients of Cheese
Almost all natural cheese is made from a combination of these four ingredients:
- Milk: The foundation. This can come from cows, goats, sheep, or even buffalo, with each type contributing unique flavors and textures.
- Starter Culture (Bacteria): These are friendly bacteria added to the milk. They consume the milk’s sugar (lactose) and convert it into lactic acid, which is essential for curdling and developing the cheese’s flavor and aroma.
- Rennet (Coagulant): This is an enzyme that causes the milk to set or coagulate. It clumps the milk proteins (casein) together, separating the solid curds from the liquid whey.
- Salt: Added for flavor, to control moisture, and as a preservative to ensure the cheese ages properly without spoiling.
The Basic Steps of Cheesemaking
While the exact process varies greatly for different cheeses (like a soft Brie versus a hard Parmesan), the basic flow remains the same:
| Step | Process | What’s Happening |
| 1. Acidification | A starter culture (bacteria) is added to warmed milk. | The bacteria convert lactose into lactic acid, lowering the pH and preparing the milk for coagulation and flavor development. |
| 2. Coagulation | Rennet is added to the milk. | The enzyme causes the milk to solidify into a gel-like mass, separating the solids (curds) from the liquid (whey). |
| 3. Cutting & Cooking | The solid curd is carefully cut into small pieces and often gently heated and stirred. | Cutting the curd increases its surface area, which, along with the gentle cooking/stirring, forces the curds to shrink and expel more whey. The smaller the cut, the harder (drier) the final cheese. |
| 4. Draining & Shaping | The whey is drained off, and the remaining curds are collected, sometimes pressed, and placed into molds (hoops). | This is where the curds are formed into the final shape of the cheese wheel or block. Pressing removes any remaining moisture. For some cheeses like Cheddar, the curds are matted, cut, and stacked (cheddaring) before pressing. |
| 5. Salting | Salt is either mixed directly into the curds or the finished cheese is soaked in a salt brine. | Salt adds flavor, acts as a preservative, and helps draw out the last bit of moisture to stop the bacteria from producing too much acid. |
| 6. Ripening (Aging) | The shaped cheese is moved to a controlled environment (like a cave or aging room) to mature. | Over time (from a few days to several years), enzymes and molds continue to work on the cheese, breaking down proteins and fats to develop its complex flavors, aromas, and signature texture. This is where “moldy cheese” gets its character! |
Now, imagine trying to make cheese as an experiment in the classroom. It could be fun. However, maybe don’t eat the experiment just to be safe.
Quick & Easy Homemade Ricotta-Style Cheese
This recipe uses a simple acid (vinegar or lemon juice) and heat to separate the curds and whey, a process known as acid coagulation.
Ingredients
| Ingredient | Quantity | Notes |
| Whole Milk | 8 cups (2 quarts) | Crucial: Do not use Ultra-Pasteurized (UHT) milk, as the high heat treatment prevents it from curdling properly. |
| Heavy Cream (Optional) | 1/2 cup | Adds richness and a creamier texture. |
| Distilled White Vinegar or Fresh Lemon Juice | 1/3 cup | This is your acid coagulant. |
| Salt (Kosher or Sea Salt) | 1 teaspoon | For flavor. |
Equipment
- Large, heavy-bottomed pot
- Slotted spoon or ladle
- Fine-mesh strainer or colander
- Cheesecloth (or a clean, thin kitchen towel)
- Kitchen thermometer (optional, but very helpful)
Instructions (Ready in under 45 minutes!)
1. Heat the Milk and Cream (5-10 minutes)
- Pour the milk, cream (if using), and salt into your large pot.
- Heat the mixture over medium heat, stirring occasionally to prevent the milk from scorching on the bottom.
- Bring the temperature up to about 195°F (90°C). This is just before a full rolling simmer—you will see plenty of steam and tiny bubbles forming around the edges.
2. Add the Acid and Coagulate (10 minutes)
- Remove the pot from the heat.
- Pour in the vinegar or lemon juice. Stir slowly and gently a few times (about 3–4 seconds) to incorporate the acid. Do not over-stir.
- Cover the pot and let the mixture sit, undisturbed, for 10 minutes. The mixture should visibly separate into solid white clumps (the curds) and a clear, yellowish liquid (the whey). If it hasn’t separated fully, add a teaspoon more acid and wait 2 more minutes.
3. Strain and Drain the Cheese (10-30 minutes)
- Set up your strainer over a large bowl (to catch the valuable whey) and line it with a double layer of cheesecloth.
- Use your slotted spoon or ladle to carefully scoop the large curds into the cheesecloth-lined strainer.
- Once all the curds are in the strainer, you can pour the remaining whey mixture through to catch any fine curds.
- Drain for the desired texture:
- 5-10 minutes: Will yield a soft, wet, creamy cheese—perfect for spreading on toast or eating with a spoon.
- 20-30 minutes: Will yield a firmer, drier cheese—ideal for using in lasagna, ravioli, or baking.
4. Finish and Serve
- Gather the corners of the cheesecloth and lift the cheese out of the strainer. Give it a gentle final squeeze if you want it firmer.
- Transfer the fresh cheese to a bowl. Give it a taste and add a pinch more salt or a grind of black pepper, if desired.
- Serve immediately while warm, or cover and refrigerate for up to a week!