The buttermilk vs. heavy cream debate has been raging ever since the first cave-person decided to use cow’s milk for cooking stuff (probably).

Both buttermilk and heavy cream are staples of baking. Biscuits, cakes, scones, waffles… if it’s baked and conjures up memories of your mee-maw’s kitchen table on a hot summer’s day, there’s a way to do it with buttermilk or heavy cream. You can also use them for sauces, marinades, and a whole bunch of other goodies.

They both crop up in a lot of recipes.

Some folks think they’re completely interchangeable. Those folks are wrong. We’re going to settle the buttermilk vs. heavy cream debate once and for all (or at least until new research changes our minds).

Despite the fact they’re both made by doing stuff to milk, buttermilk and heavy cream are very different. You make buttermilk by inducing fermentation in milk with lactic acid. Heavy cream, on the other hand, comes from skimming the fat from unhomogenized milk.

Skimmed milk fat and fermented milk produce very different tastes and textures. Here’s an overview on both, from how they’re made to what they do (and why cookery folks love them for it).

What is buttermilk?

Bakers love buttermilk. It gives muffins, pancakes, and biscuits a tender, moist texture. If you love a cake because it’s light and fluffy, chances are you have buttermilk to thank.

As far as flavor goes, it’s tangy. That’s because it’s acidic. You might balk at the idea of acidic cakes, but acid reacts with baking soda, causing those cakes to rise like Hermione Granger’s hand when there are house points to be won.

Traditional buttermilk is a little different from the buttermilk you find on grocery store shelves. Way back when, buttermilk was just the liquid left over when you made butter. That’s how it got its name — it’s literally “the milk of the butter” (which is made of milk, leading to a weird Milkception scenario that it hurts to think about too much).

This “traditional” buttermilk was a lot like soured, low fat milk. Modern buttermilk is closer to yogurt, and we make it in a much fancier way than decanting the watery stuff left over from butter making.

The buttermilk you buy in stores is a thick yogurt-like substance made by adding lactic acid bacteria to milk. This ferments it in a way that makes buttermilk instead of just the regular off-milk you accidentally drank when you were half asleep this morning.

What is heavy cream?

Heavy cream is sometimes called heavy whipping cream. As the name suggests, it’s a cream that’s not light and is good for whipping (yes, Hermione, 10 points to Gryffindor). You make cream by leaving milk out for a bit before homogenizing it.

If you leave milk for a while, the fat rises to the top. This is then skimmed off (which is also why we refer to milk as skimmed, semi-skimmed, and what have you). The fat-skimmed milk travels off in bottles for our cereal, and the skimmed-off cream goes into pressurized metal cans for dessert-making purposes.

Heavy cream is cream with a fat content of 30 to 40 percent (which is what makes it so gosh-darned delicious when you bake stuff with it). Outside of baking, it can also be used for soups, homemade butter, sauces, sour cream, and everybody’s favorite anything, ICE CREAM.

In baking, cream gives cakes, scones, biscuits, and lots of other yummy treats a rich, full texture. It’s also popular because, of all the whippable creams, heavy cream is known to hold its shape the longest.

Presentation is super important in the world of pro dessert making, so a cream that holds its shape on the way from the kitchen to the table is always going to have a following amongst chefs and patissiers.

While there are ways to substitute buttermilk/heavy cream for each other, there are recipes that call on them for specific qualities which the other doesn’t have.

  • You can’t whip buttermilk. If the recipe calls for heavy cream because of its whippable-ness, buttermilk is firmly off the table.
  • Buttermilk is low fat. A recipe might call for heavy cream because of the 30 to 40 percent fat content. If that’s the case, buttermilk is just too light for the job.
  • Heavy cream doesn’t react with baking soda. Buttermilk is acidic, and when you mix it with baking soda, the reaction makes whatever you’re cooking rise. In the world of cakes and baking, getting the rise right is pretty darn important. An unrisen cake isn’t a cake, it’s a mess. If your recipe relies on buttermilk as a leavening agent, heavy cream won’t do.
  • Buttermilk has a sour taste. Sometimes, bakers add buttermilk because of its unique sour taste. This is especially true in biscuits and scones. Heavy cream, lacking the sourness, isn’t up to this task.
  • Both have distinct textures. As a rule of thumb: buttermilk = light and fluffy, and heavy cream = thicc and rich. If a recipe calls for either based on these qualities, swapping them probably won’t work.

So long as you’re not using them for the above reasons, it isn’t too challenging to swap one for the other. Yeah, it might require some bakery skills, but you don’t have to be Adriano Zumbo to pull it off.

There are two key buttermilk functions your heavy cream will struggle to fill. The first is buttermilk’s token sour taste. You might be able to sub in a splash of lemon or vinegar, depending on the recipe.

The second is buttermilk’s role as a leavening agent. Heavy cream doesn’t react with baking soda, and so doesn’t make cakes, bread, or anything else rise. Replacing your baking soda with baking powder can do the trick here.

Remember, traditional buttermilk is different than the store-bought kind. If you’re after traditional buttermilk, you can actually use cream, milk, and some vinegar/lemon to make your own buttermilk from home.

Buttermilk and heavy cream fill similar roles in some recipes but are very different. The buttermilk we buy in stores is made by introducing lactic acid to milk, and it has a tangy taste. Budding bakers use it to add flavor and to make cakes, bread, and other baked goods rise. It’s also used for marinades.

Heavy cream is risen fat skimmed from unhomogenized milk. It’s thicc, can be whipped, has 30 to 40 percent fat content, and adds a sweet creaminess to dishes. It mainly cameos in baking, ice cream, and desserts.

They’re not completely interchangeable. Yes, you can swap them in a recipe, but it’s not as simple as switching buttermilk for heavy cream/heavy cream for buttermilk. For example, if you’re replacing buttermilk with heavy cream you’ll probably need to switch out your baking soda for baking powder.

There are plenty of recipes for buttermilk-free or cream-free recipes. There are also plenty of dairy-free alternatives for both. However, as with all substitutions and ingredient switch-ups, the final taste and texture may vary regardless of how good you are in the kitchen.