Homemade Ricotta Cheese
Updated: Apr 17, 2020
Cooked by Celine S
Written by Saki A
Yield: makes about 2 cups
1/2 gallon of milk
1 cup heavy cream
1/2 teaspoon salt
large sieve, fine-mesh cheesecloth (alternate options: coffee strain, old-tshirts -- tried both and can confirm that they work just fine)
Line a large sieve with a layer of cheesecloth and place it over a large bowl.
Slowly bring milk, cream, and salt to a rolling boil in a 6-quart heavy pot over moderate heat, stirring occasionally to prevent scorching. Add lemon juice, then reduce heat to low and simmer, stirring constantly, until the mixture curdles, about 2 minutes.
Pour the mixture into the lined sieve and let it drain. After discarding the liquid, chill the ricotta, covered; it will keep in the refrigerator 2 days.
How does milk turn into cheese?
The acidic lemon is the real MVP here. Normally, little groupings of milk proteins called casein freely float around, without bonding to anything else. However, when milk becomes more acidic as either lemons get added or the milk turns old and sour, the caseins start to clump together. The proteins are usually negatively charged and repel others, but the positively charged acid effectively neutralize them so they can start sticking to each other (and turn into cheeeese)! For other kinds of cheese like gouda and cheddar, special bacteria are used to add positive charges instead of lemons.
Now, who discovered this? Though we don't really know the origin of cheese making, it is thought to be an accidental discovery made when storing milk in stomachs of animals (enzymes in the stomach can also curdle milk). The art of cheesemaking is referred in ancient Greek myth and on Egyptian tomb murals painted over 4000 years ago.
Recipe adapted from Epicurious: https://www.epicurious.com/recipes/food/views/fresh-homemade-ricotta-234282
History of Cheese. National Historic Cheesemaking Center (2017) https://nationalhistoriccheesemakingcenter.org/history-of-cheese/
Cheesy Science. American Chemical Society (2018). https://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/2017-2018/december2017/cheesy-science.html