HOMEMADE CRÈME FRAÎCHE
Crème fraîche is made by allowing heavy cream to spoil in a
controlled way. Bacteria introduced into the cream convert
some of its sugar (mainly the complex carbohydrate lactose)
into simpler sugars and acidic by-products. This lowers the
pH of the cream, causing some of its proteins to coagulate,
making it thicker. Good crème fraîche has a rich, creamy
texture, stiff enough to form loose peaks, and a tangy,
slightly cheese-like flavor. Store-bought crème fraîche is
great, but it can be difficult to track down and pricey. When
I found out that you can simply mix buttermilk (which has
live bacterial culture) into heavy cream and let it thicken
overnight to create a true crème fraîche at home, my mind
was blown. I like to share my mind-blowing experiences, so
here you go. Lucky you!
I played around with the ratios of cream to buttermilk
quite a bit and in the end found that it doesn’t really matter
all that much. Add more buttermilk, and you’ll need less
time for it to thicken, but it’ll be less creamy. Add less, and
it takes longer, but tastes better. One tablespoon per cup
(that’s a 1:16 ratio) was about the perfect balance for me.
It gets superrich and creamy at right about the 12-hour
mark. You can halt the process earlier by refrigerating it to
stop the bacterial action—this is useful if you want a thinner
Mexican-style crema agria for drizzling over your nachos
or guacamole. For those of you worried about cream
spoiling at room temp, that’s the idea: it’s the good bacteria
from the buttermilk multiplying in there that prevent the
dangerous bacteria from taking over.
And let the mind-blowing begin. Commence countdown.