Have you ever taken cream out of the refrigerator to use a bit of it, and then when, a few hours later, you notice that you never put it back, said to yourself, “I wonder how long that stuff can sit out for?” Well, that turns out to be an interesting question.
Milk contains a sugar called “lactose,” which is found almost nowhere else in nature. Because lactose is unique, most microbes have evolved to eat other kinds of things that are easier to find. There are only a few types that can digest lactose, and they happen to be human-friendly. They produce lactic acid – as well as other antibacterial substances – which retard the growth of other types of microbes, many of which are harmful to humans. Lactic acid also has a duel effect of thickening milk while creating a pleasantly tart taste. What I’m describing is a family of foods with which you’re quite familiar: sour cream, buttermilk, and – if you’re a foodie – crème fraîche.
Lactose-eating microbes are abundant in nature. They live in and on plants and animals (including you). Back when daily life and nature were more homogenous, if you left milk out, chances were decent that these microbes would find it. Today, in the relatively unnatural environment of climate-controlled high-rise condos and Lysol, we tend not to want to leave it to chance.
That’s where buttermilk comes in. You might notice that your container of buttermilk doesn’t say merely “buttermilk,” but it says “cultured buttermilk.” That’s because commercial buttermilk is not – contrary to common opinion – the byproduct of making butter. Instead, it is skim milk that has been fermented with lactose-eating microbes, to produce something very similar to the byproduct of butter-making. These microbes are still alive and very much at work in the buttermilk you buy at the store. If you introduce them to a cup of cream, you’ll make their little lives joyful, and they’ll reward you by turning that cream into crème fraîche.
So, although you might not want to leave a cup of cream out overnight, add a tablespoon or two of cultured buttermilk, and you can and should leave it out. As with other types of fermentation – like yeast-risen breads – introducing fewer microbes will cause the process to take longer, but it generally results in better flavor. And, like bread-making, doing it by hand at home produces so many variables that you can’t expect exactly the same results every time. Although it hasn’t ever not worked, I sometimes get crèmes that are thicker or thinner, or anywhere from pretty tasty to very tasty.
If I had all the time in the world, I’d make everything at home that I conceivably could: yogurt, sour cream, cheese, beer … you name it. But I don’t have all the time in the world. I have just small fractions of each day, in fact. I fell into bread-making many years ago, and I still love that. But most other things, I’m content to buy from the store. Crème fraîche, however, is not easy to find. Most groceries don’t carry it. So I do make it at home.
Although it’s great for cooking, I typically use it as a garnish or accompaniment. I think of crème fraîche as something half-way between whipped cream and sour cream, and I use it with cakes, pastries, and fruit – or I’ll splash a dollop into a serving of a thick soup. It is especially delicious with anything you’d normally garnish with whipped cream, but to which you’d like to add a hint of tang: spice cake, pumpkin pie, dark chocolate pudding. Of note: if you have buttermilk and heavy cream, and you turn the cream into crème fraîche, you could substitute the crème fraîche for sour cream in a Buttermilk Ranch salad dressing.
Homemade crème fraîche:
What you need to make 1 cup :
8 oz. heavy cream
1-2 Tbs buttermilk
How to do it:
So simple: pour cream into a glass container. Add buttermilk. Stir. Cover, and allow to stand at room temperature for 12-24 hours. Then, refrigerate. Pretty easy!
Credit for images on this page: Make It Like a Man! This content was not solicited – not by the American Dairy Association, nor the Culinary Institute of America’s Fresh Cheese Boot Camp … not even the International Association for the Advancement of È and Î – nor was it written in exchange for anything, like a special keyboard with è and î keys. In doing research for this recipe, I relied on articles by Epicurious, Serious Eats, and “On Food and Cooking,” by Harold McGee. Scribner, NY, 2004. Regarding the latter, if you love to cook and you have a curious mind, you absolutely must read this book.
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