Basics | French | My Recipes
Crème Fraîche (How to Make It at Home)
This is how you make crème fraîche—the French cultured cream that’s richer than sour cream and more versatile than yogurt. Heavy cream mixed with buttermilk, left at room temperature for 12-24 hours, then chilled. That’s it. The live cultures in the buttermilk ferment the cream and thicken it into something tangy, rich, and luxurious.
The technique is simple but the science matters. You need regular pasteurized cream, not ultra-pasteurized—the high heat kills the proteins needed for culturing. You need buttermilk with active cultures—that’s what ferments the cream. Room temperature means 68-75°F. Too cold and it won’t culture. Too hot and it spoils. Time does the work.
Crème fraîche finishes sauces without curdling like sour cream. It tops soups without breaking. It whips into dessert cream with sugar. It goes on smoked salmon, fresh berries, borscht, pasta, risotto. Once you have it in your fridge, you use it constantly.
Crème Fraîche (How to Make It at Home)
French cultured cream made with heavy cream and buttermilk. Tangy, rich, versatile. Takes 5 minutes of work, 12-24 hours to culture. Use it on everything.
Ingredients
Method
- Pour heavy cream into a clean glass jar or bowl. Stir in buttermilk until combined.Cover loosely with a clean kitchen towel or cheesecloth secured with a rubber band. You want air circulation, not an airtight seal. The cultures need oxygen to work.Let sit at room temperature (68-75°F) for 12-24 hours until thickened to the consistency of sour cream. The warmer your kitchen, the faster it will thicken. In cooler kitchens, it may take the full 24 hours. Check it after 12 hours by tilting the jar—if it coats the sides and moves slowly, it's ready.Once thickened, stir, cover tightly with a lid, and refrigerate. It will continue to thicken as it chills. Use within 2 weeks.
Notes
Ultra-Pasteurized Cream Won’t Work: The high heat processing (280°F) kills the proteins needed for culturing. Regular pasteurized cream is heated to 161°F—hot enough to kill harmful bacteria but gentle enough to leave the proteins intact. Look for heavy cream or heavy whipping cream labeled “pasteurized,” not “ultra-pasteurized.” Check the label carefully. Most organic creams are regular pasteurized. Most conventional creams are ultra-pasteurized. If the label says “ultra-pasteurized,” it will not culture. You’ll end up with liquid cream mixed with buttermilk that never thickens. Use the right cream or don’t bother.
Buttermilk Must Have Active Cultures: The live cultures (usually Lactococcus lactis or Leuconostoc mesenteroides) are what ferment the cream. Check the buttermilk label—it should say “contains active cultures” or “live cultures.” Most grocery store buttermilk has this. If the label doesn’t mention cultures, don’t use it. Powdered buttermilk won’t work—it has no live cultures.
Will Lowfat Cultured Buttermilk Work? Yes. Lowfat, reduced-fat, or whole milk buttermilk all work. You’re using the buttermilk for the live cultures, not the fat content. The cultures are what matter. As long as the label says “active cultures,” you’re good. The richness of the crème fraîche comes from the heavy cream, not the buttermilk. One tablespoon of buttermilk is enough to culture an entire cup of cream.
Temperature Matters: Room temperature means 68-75°F. This is the ideal range for the cultures to multiply and ferment the cream. If your kitchen is cold (below 65°F), the culturing will take longer—up to 36 hours. The cultures are sluggish in cold temperatures. If your kitchen is warm (above 75°F), it will thicken faster—sometimes in 8-10 hours. The cultures are more active in warmth. But don’t let it sit in a hot kitchen (above 80°F) or it can spoil instead of culturing. The line between culturing and spoiling is temperature control.
How to Tell When It’s Done: The crème fraîche should be thick enough to coat the back of a spoon and move slowly when you tilt the jar. It should taste tangy and rich—like a less sour, thicker, creamier version of sour cream. The tang comes from lactic acid produced by the cultures. If it’s still liquid after 24 hours, let it sit longer or check your cream—if it’s ultra-pasteurized, it will never thicken. If it tastes or smells off (sour in a bad way, bitter, or rancid), discard and start over. Properly cultured crème fraîche smells fresh and tangy, not spoiled.
Why Cover Loosely, Not Tightly: The cultures need oxygen to ferment the cream. A loose cover (kitchen towel or cheesecloth) allows air circulation while keeping dust and debris out. An airtight lid will slow or stop the culturing process. Once the crème fraîche is thickened and refrigerated, then you seal it tightly to prevent it from absorbing fridge odors.
Refrigeration Stops the Culturing: Once you refrigerate the crème fraîche, the cold temperature slows the cultures to near dormancy. The fermentation mostly stops. The crème fraîche will continue to thicken slightly in the fridge as it chills, but the flavor won’t change much. This is why it keeps for 2 weeks—the cold prevents over-fermentation and spoilage.
Scaling: This recipe makes 1 cup. Double, triple, or quadruple as needed. Use 1 tablespoon buttermilk per cup of heavy cream. The ratio stays the same. Don’t go larger than 4 cups at a time or the culturing may be uneven—the cultures at the top may ferment faster than the bottom. For large batches, use multiple jars instead of one giant container.
Storage: Keeps refrigerated in an airtight container for up to 2 weeks. After 2 weeks, the flavor becomes more sour and intense as the cultures continue working slowly in the fridge. Some people like this—others find it too tangy. Use your judgment. If it smells or tastes off, discard.
Uses: Crème fraîche is more versatile than sour cream because it doesn’t curdle when heated. Use it in hot applications where sour cream would break: Stir into pan sauces for richness without curdling (deglaze a pan, add crème fraîche, it stays smooth). Finish pasta or risotto (stir in at the end for creamy, tangy richness). Dollop on hot soups (borscht, tomato soup, butternut squash soup, potato leek soup). Top smoked salmon, caviar, or blinis for elegant appetizers. Serve with fresh berries or fruit tarts (the tang balances sweetness). Whip with sugar and vanilla for dessert topping (lighter than whipped cream, tangier than mascarpone). Use in baking as a substitute for sour cream (cakes, muffins, biscuits—adds moisture and tang). Spread on warm bread or scones. Mix with fresh herbs for a quick sauce or dip. Top baked potatoes, tacos, or chili.
Why Make Your Own: Store-bought crème fraîche costs $6-8 for 8 ounces. Homemade costs about $2 for 8 ounces (the price of 1 cup of heavy cream plus 1 tablespoon of buttermilk). The flavor is fresher and the tang is brighter. You control the thickness by how long you let it culture. Once you make it, you’ll never buy it again. It’s one of those things that seems fancy but is actually dead simple.
Troubleshooting:
Still Liquid After 24 Hours: Your cream is ultra-pasteurized. Check the label. Start over with regular pasteurized cream. Or your kitchen is too cold—move the jar to a warmer spot (near the stove, on top of the fridge) and give it another 12 hours.
Tastes or Smells Off: It spoiled instead of cultured. This happens if the jar wasn’t clean, if the kitchen was too hot (above 80°F), or if the buttermilk didn’t have active cultures. Discard and start over. Make sure the jar is clean, the buttermilk has live cultures, and the room temperature is 68-75°F.
Too Thick: Stir in a tablespoon of heavy cream or milk to thin it out. Crème fraîche thickens as it sits in the fridge. If it gets too thick after a week, just loosen it with a little cream.
Too Thin: Let it sit at room temperature for another 6-12 hours to thicken more. Or use it as is—thinner crème fraîche still tastes good, it just won’t hold its shape on a spoon.
Not Tangy Enough: Let it culture longer—up to 36 hours at room temperature. The longer it cultures, the tangier it gets. Taste it every few hours after the 12-hour mark until it reaches your preferred level of tang.
Separated (Watery Liquid on Top): This is whey—completely normal. Just stir it back in. Crème fraîche can separate slightly as it sits in the fridge. The whey rises to the top. Stir it back into the cream and it will re-emulsify.
French Technique: Crème fraîche is a staple in French cooking. It’s used in sauces (think mushroom cream sauce, leek and mustard sauce), soups (vichyssoise, French onion soup garnish), and desserts (tart toppings, mousse). The reason it’s so popular in French cuisine is because it doesn’t break when heated like sour cream does. You can add it to a hot pan and it stays smooth and creamy. This makes it essential for finishing sauces without curdling. Master this technique and you’re cooking like a French chef.
