Update: Please check out my new, simpler method for making sour cream, which can be found here.
In my continuing quest to recreate my Grandma Poss's caramel frosting recipe that has been lost for over 20 years (That's another blog post coming soon. Update: The recipe has been found!), I recently experimented with souring cream. After a couple tries, I produced a concoction deliciously tangy and thick. Did I make crème fraîche or sour cream or is this a subtlety of little significance? Let's find out. The difference between sour cream and crème fraîche is apparently hot Internet discussion topic among foodies, but one lacking knowledgeable content, in my humble opinion (or not so humble, considering I worked in dairy education and communications for 15 years). I hope this post makes a useful contribution in the cultured cyber-food world.
In the United States, federal regulations define many staple foods. Those definitions are called Standards of Identity and stipulate ingredients, fat content, moisture content or other attributes. Standards of Identity exist for many dairy products, including varieties of milk, heavy versus light cream, sour cream, cheese versus cheese product, butter, cream cheese, ice cream, yogurt, etc. These defintions exist to ensure truth in labeling and with dairy foods, it's to ensure those products made and processed in particular ways using all or a portion of cows'milk and not imitations or watered-down ingredients.
The Standard of Identity
- Heavy cream: Cream with minimum fat content is 36% of the total weight.
- Light whipping cream: Cream which contains 30% - 35.99% milkfat.
- Light cream: Cream which contains 18% - 29.99% milkfat.
- Half-and-half: A mixture of milk and cream which contains 10.5% 17.99% milkfat.
- Sour cream results from the souring, by lactic acid producing bacteria, of pasteurized cream. Sour cream contains not less than 18% milkfat.
Notice, I didn't include buttermilk or crème fraîche. Standards of identify exist for cultured milk and acidified milk but not for buttermilk, and Crème fraîche is French. Que peux-je dire? Standard of Identity or not, Crème fraîche is a slightly soured cream containing a relatively high butterfat content (about 28% by weight). Commecial buttermilk is typically made by adding lactobacillus bacteria to reduced fat or lowfat milk. However, as I learned from a recent foray into Boulder area grocerires, store-bought buttermilk often does not contain live cultures.
The science behind cultured dary foods, including sour cream, is fairly straight-forward. Certain non-pathogenic (not disease-causing) bacteria like to feed on the lactose present in milk and cream. Those bacteria produce acid and that acid reduces the pH of the milk or cream. The reduced pH coagulates the protein, which partially solidifies the product. Acid without bacteria can be used to coagulate dairy proteins, as with one version of home-made ricotta cheese that calls for vinegar.
The key to making sour cream or crème fraîche is having a starter culture. While I have run across several web posts suggesting the use of buttermilk as a starter, the buttermilk has to contain active cultures. Here's the outcome of my kitchen experiment with souring cream.
Batch 1: Along with heavy cream, I purchased buttermilk assuming all store-bought buttermilk had live cultures...my bad. Preparing to start souring the cream, I re-read the directions and took a closer look at the buttermilk carton only find it had no cultures in the list of ingredients. Saving the buttermilk for another cooking foray, I decided to take my chances and start the process with store-purchased sour cream, hoping it had enough live cultures to make the fresh cream sour. I placed 3 heaping tablespoons of sour cream and 1 pint of heavy cream in a quart mason jar, placed the lid on the jar and let it set on the kitchen counter for 24 hours. (Added October 19 - thanks for the nudge, Connie: Nothing happened, so down the drain it went.)
Batch 2: I pulled out all the punches and purchased plain whole milk yogurt with an ingredient list specifying individual bacteral cultures, including Lactobacillus bacteria: L. bulgaricus, L. acidophilus and L. casei (all lactic-acid producing bacteria). Thank you, Horizon Organic Dairy, for listing the cultures. (Disclosure: I was the manager of consumer communcations for Horizon Organic Dairy about 10 years ago.) So Batch 2 was comprised of 3 heaping tablespoons of whole milk yogurt and 1 pint of heavy cream, again in the quart mason jar covered with a lid. I decided to speed up the process by placing the jar in the oven and intermittently turning on the oven to 100 degrees Fahrenheit. Once per hour I heated the oven to 100 degrees, then turned it off as soon as the thermostat showed 100 degrees. Lactobacillus bacteria grow best between about 77 and 104 degrees Fahrenheit. After six hours, I could see the mixture was nicely coagulated. I let it sit on the counter another four hours, then set the jar in the refrigerator overnight. By morning I had thick sour something and it was delicious!
So back to my quesion of whether I made sour cream or Crème fraîche. Crème fraîche is typically higher in fat content than sour cream; however, the fat content of sour cream can vary. Though claims are made that crème fraîche is not as tangy or acidic as sour cream, little difference appears to exist with the actual pH (in the neighborhood of 4 to 4.5). I reviewed several posts addressing the difference between commercial sour cream and crème fraîche that indicate retail sour cream includes gums and other stabilizers. However, carageenan and guar gum are not typically added to home-fermented dairy recipes. So, here's my answer: I think I made fresh sour cream, which is another way of saying crème fraîche (fraîche is fresh in French). And I can guarantee, when Grandma Poss let cream sour in her farm kitchen, she wasn't thinking about Crème fraîche. Nein, if not sour cream, it was saure Sahne, because Grandma was German American.
I have since made two more batches of sour cream with equal success. Souring cream is a simple process, and the resulting flavor and texture are delightful. From package Nutrition Facts panel calculations, I am certain that the fat content of my home-made sour cream made from heavy cream is nearly double that of commerically made sour cream I recently purchased. I want to see if I can bring the fat content down without adversely affecting the taste and texture of sour cream, so I plan to make additional test batches with light whipping cream and half-and-half. Stay tuned.
Post featured on Prairie Story Recipe Swap Thursday.
