Make cultured butter at home from just two simple ingredients: cream and kefir, no special equipment required. Cultured butter is one of the simplest home fermentation projects and a great introduction into the transformative power of fermentation. This butter is nutty, tangy, and almost cheesy—best enjoyed simply, spread thick on warm toast.
What’s the difference between cultured and uncultured butter?
Unlike regular sweet cream butter, cultured butter is fermented for a short period of time to develop more complex flavor. It’s the critical differentiator between regular butter from the grocery store and luxury butters from Maison Bordier, Isigny, Les Pres Sales, and the likes. Beneficial bacteria like Lactococcus lactis break down lactose in the cream to make lactic acid, that tangy cheesy flavor, and diacetyl, a natural compound added to movie theater popcorn and baked goods for its buttery flavor. These beneficial bacteria also make the environment inhospitable to pathogenic bacteria, preserving dairy for longer.
I use kefir in my recipe because the live and active cultures in kefir are typically mesophilic, meaning they thrive in moderate room temperatures. Other recipes may call for a specialty kefir, which is harder to find. Some recipes recommend using yogurt, which is thermophilic, meaning it thrives with warmer temperatures and requires a special setup for maintaining a warm environment closer to 100°F.
How does cream turn into butter?
Dairy cream is an emulsion of fats wrapped in membranes suspended in water. Agitating the cream breaks the membranes around the fats, allowing them to link into a ball of butter. Agitation can be as simple as shaking the liquid in a jar, or to save your strength, mix the cream in a food processor or stand mixer. The liquid that separates from the fat is buttermilk. It tends to be thinner and milder than the buttermilk sold in cartons at the store. Strain it and store it in the refrigerator for making baked goods or pancakes.
How long does homemade butter last?
The key factors affecting butter’s shelf life are moisture and air. Butter is mostly fat, which is naturally resistant to bacterial growth, but the small amount of water it contains can harbor microbes. Packing your butter tightly in an airtight container and covering the surface with a layer of parchment or wax paper helps limit exposure to air. Cultured butter is naturally more resistant to spoilage than sweet cream butter, giving it a slightly longer fridge life.
Homemade cultured butter typically lasts for up to 1 month store in the refrigerator or up to 6 months in the freezer. Always use a clean butter knife or spreader to keep your butter tasting fresh.
Homemade Cultured Butter
Ingredients
- 2 cups heavy cream
- 2 tablespoons kefir
- 1/2 teaspoon flaky sea salt sub 1/2 teaspoon Diamond Crystal kosher salt or 1/4 teaspoon table salt
Instructions
- In a medium bowl, stir together the heavy cream and kefir until evenly combined. Cover with plastic wrap or a lid and leave in a warm place (between 65 to 85°F) for 12 to 36 hours. The cream will develop a tangy flavor and may form a thickened layer on top as it ferments. Ferment for 12 hours for a milder flavor or ferment for a full 36 hours for a cheesier tasting butter. The warmer end of the temperature range will ferment faster, hence the wide time range.
- Transfer the cream mixture to a large jar with a tight fitting lid. Shake until yellow clumps of butter form, about 5 to 10 minutes. At first the mixture will resemble whipped cream, then it will break into a grainy or curdled consistency before it clusters together and fully separates from a layer of thin, milky liquid. Alternatively, transfer the cream mixture to a stand mixer or food processor and beat until the butter separates, about 10 minutes.
- Set a fine mesh strainer over a medium bowl. Fill a large mixing bowl halfway with water and a few ice cubes. Strain the butter and reserve the liquid—this is cultured buttermilk. Store the buttermilk in an airtight container in the refrigerator and use for smoothies or baking (makes great waffles and pancakes). Transfer the ball of butter to the bowl of ice water and knead to release buttermilk. Pour off the ice water and refill with ice water, continuing to knead, rinse, and refill until the water runs clear.
- Pour off the water one final time and press the butter to drain off any excess water. Knead in the salt if using. Press the butter to an airtight container, avoiding air pockets to the best of your ability, and cover with parchment. Store in the refrigerator for up to 1 month.
Hi Mei, long time reader! I want to make this but everything in me screams against leaving dairy out at room temp. Am i understanding that part correctly?
Ironically i’ve made yogurt before but have no problem leaving that overnight because it was “heated up” i guess?
I just want to confirm that is indeed what you mean so i don’t poison us 🙂 thank you!
Ps. I want to get comfortable with feementation and canning too but i’m scared to do it wrong.
Hi Mirayumyum, the kefir cultures thrive at room temperature to outcompete harmful bacteria and drop the pH of the dairy. It’s not much different than making yogurt, only the kefir bacteria just prefer a slightly cooler temperature.
How much salt do you use? Thanks!
Hi Lauren, I recommend using 1/2 teaspoon of flaky sea salt in the recipe. Volume substitutions for other types of salt are in the ingredient notes.
Can you use a flavored kefir to make a flavored butter, such as raspberry? What would happen with the buttermilk?
You’re not adding a significant enough kefir to give it a strong flavoring. If you used flavored kefir, likely the butter would just taste slightly off.
However! Compound butter is a thing! If you follow the recipe up until putting it away, you can mix in herbs and spices (I’ve never heard anyone trying raspberry compound butter though) and it will work great.
Do you also use the thickened layer on the fermented cream when shaking or do you discard that first?
I have been wanting to make my own butter for a while, and your TikTok finally pushed me to try it! I let the mixture ferment for 18 hours…I think I will do more next time to get more tang!
This butter was a crowd pleaser for a family gathering, alongside homemade sourdough bread. I doubled the recipe and it made about 3.5 cups of butter (413 g). This was more than plenty for a party of 10, and I had a couple portions left for the hosts, some to wrap in parchment and share with a friend, and some left at home for me.
Adding: I used a hand mixer for mixing. It worked well, but I would put it in a larger bowl next time because of light splattering (especially since I doubled the recipe). I also learned that next time I will have everything I need for the kneading in cold water step in advance. I underestimated how buttery my fingers would get and that made it a lot messier to add more ice water, or grab a separate dry bowl for the finished kneaded butter. 🙂