Place the whipping cream and buttermilk into a mason jar or glass bowl.
Shake or stir well to combine the heavy cream with the buttermilk.
Cover the container with a piece of cheese cloth or a paper coffee filter. Place the container in a warm area of the kitchen. On the counter is fine but not in a draft or direct sunlight.
Allow the crème fraiche to culture for 12-24 hours.
After 6-12 hours check to see if the crème fraiche has thickened.
It should be as thick as sour cream or thicker. If not, recover and wait another 4 to 6 hours for it to culture.
Once cultured and thickened refrigerate for an hour to chill before using. As it chills it will thicken further.
Recipe Expert Tips
Pasteurized dairy: can you use ultra pasteurized dairy buttermilk or heavy cream?: Yes you can to make crème fraiche.
Culturing time: the culturing time of cream and buttermilk will depend on the temperature of your home. Colder homes will take longer while warmer homes will take less time. 12 to 24 hours is an estimate.
Crème Fraiche Starter: For your second and any future batches of crème fraiche you will reserve about ⅓ of a cup of your batch of crème fraiche to use as a starter. Put it into a pint jar and fill the pint jar full of heavy whipping cream. Leave enough head space so you can shake it up a bit while it is culturing. Leave for 24 hours and then refrigerate.
How long does it last? Fresh made will stay good for as long as store bought as long as it is kept properly refrigerated.
How to us a mother batch of homemade crème fraiche to culture the next batchUse your mother batch of homemade crème fraiche to culture continuous future batches of crème fraiche. Using ¼ to ⅓ cup of the mother cultured crème fraiche to make the next batch.
Place ¼ to ⅓ cup of crème fraiche in a jar.
Add 2-3 cups of heavy whipping cream to the jar and shake to combine.
Following the same culturing steps in the original recipe to culture this batch.
This second batch of cultured buttermilk and heavy cream will thicken up much faster than the first. So check it frequently.