As part of my Science & Cooking course, one of the labs (yes, there actually are labs to do at home!) is to make ricotta cheese. But first a bit of explanation.
As part of a week introducing us to the role of energy, heat and temperature in cooking. Part of this was exploring how proteins can be changed at different temperatures, specifically looking at cooking eggs at very exact temperatures in order to get particular textures.
Other aspects included measuring and quantifying the amount of heat needed to change the temperature of a food, including its specific heat.
To develop these skills further, one of the possible labs was to make ricotta cheese from ordinary milk. The milk is heated to 92C (thanks to our lab assistant for the loan of the thermometer!):
Vinegar is then added and the mixture is left to cool down undisturbed. As it cools, the proteins in the milk clump together to form curds. Once it reaches 36C, you put the mixture of solid curds and liquid whey into a strainer so the whey drains through. Here it is partway through: