Botched the Mozz

So, we goofed up. In lab we made mozzarella cheese, and while it was mostly successful, the most important last steps were fatal. Curse you, microwave.

First, we prepared the Citric Acid and Rennet by combining them with water. Then, we poured half a gallon of raw milk into the pot and added the citric acid solution, then heating it until 90°F.

After it reached temperature, we removed the pot from heat and gently stirred in the rennet solution, and then let it sit for five minutes. After it set, and looked something akin to silken tofu, we attempted to cut it into uniform curds in a grid-like pattern. It slid around as we did so, making it difficult, but we ended up successful.

We warmed the curds to 105°F, stirring to make sure they didn’t break up too much, and the curds clumped together and separated from the yellow whey.

After the stirring time, we removed the curds from heat and stirred for another five minutes. Then, we strained the curds out and set the whey aside.

Here’s where we started falling apart; when we put our cheese into the microwave the first time, it melted and ended up getting mixed back in with the whey.

This is me attempting to save as much of our curds from the bowl of whey.

We let it cool down and folded them together, and then repeated to get the curds to 135°F internally.

Finally, and here’s where we goofed it up the final time, we stretched and shaped the mozzarella. It looked great in the beginning. Look at that!

We sprinkled the salt over the cheese and incorporated it with our fingers, but it was too late for our poor son. I completely take the blame for overworking it, and it was surprising just how quickly something so nice can end up so terrible.

Our final product was tough and had literal layers. Layers of cheese. That’s the opposite of what should have happened. It was too salty, too tough, and overall, terrible. Because the rest of the steps went so well, I think it really came down to overworking our cheese. The melting definitely did not help, and maybe that contributed to how fast it went bad, but I overworked it, and to pay, I smelled like cheese the rest of the day.

1. When milk is lowered to a pH of 4.6, it separates into two sections: acid soluble whey proteins, and acid insoluble curds. The curds are denatured and coagulated casein, which is a protein that is particularly unstable to acid denaturation because it has so many negative charges attached to it. The whey remains in the water as a soluble protein.
2. We added the acid to the milk in order to separate the milk into its hydrophobic and hydrophilic parts. We want the proteins in the milk to denature and coagulate in order to make cheese.
3. Rennet is an enzyme in the stomach of a baby cow (can also be made from plants) that breaks apart milk proteins. It does so by cutting the negative charged tails off the casein proteins surrounding the hydrophobic milk fats. Adding the rennet allows for less acid to be used create the curds.
4. With unpasteurized milk, it would be a lot easier to create curds, as the fat globules in the milk are a lot larger and it separates into its components if left sitting. Also, the taste would probably be a lot richer, as pasteurized milk has a lesser and different taste than raw milk.