One thing must be cleared up at the start.
Crème fraîche does not count sour cream as an equal. Yes, both come from fermented cream. But sour cream may contain a minimum of 18% butterfat, while true crème fraîche must weigh in at anywhere between 30% and 40% butterfat.
Fermented food products began in the historically murky days before people thought to record their every bite. I like to think of these foods as fortuitous accidents, the kinds that happen when something tempts someone’s attention away from the task at hand.
And that brings us to a fable, sort of, a “fabulous” story. as it were.
Once upon a time, there was a young man, a cowherd perhaps, and a young milkmaid. They made sheep’s eyes at each other, hurrying through their chores, thinking of their prearranged – if not illicit – meetings behind the menhirs/cairns nestled on the hilltop behind the medieval village. This particular day, it’s late, for the chores took longer than usual, and dusk will soon darken the path to the stones. And so the young woman quickly pours some skimmed-off cream from the morning’s milking into an earthenware jug after she finishes the evening milking. But suddenly, with a dung-saturated tail, the contented cow slaps the woman’s skirt. She grabs her hair scarf and frantically rubs at the foul-smelling spot. Then she turns and runs after her paramour, forgetting all about the cream, her long brown hair fluffed by the wind.
At noon the next day, she remembers the cream, meant for making butter. She shoos away the flies. The cream lies thick in the jug, so she dips in a finger and brings it to her lips. She tastes it, sweet and tangy all at once. “Aaah,” she says out loud, “Maman will like this, I hope!”
That could be it, that Maman loved it, especially when she boiled the soup over a too-hot fire. Maybe.
Actually, it’s more likely that chefs like La Varenne served a form of whipped cream, “chantilly,” recorded in Le cuisinier françois, his cookbook written in the 17th century. But the celebrated 19th-century chef, Antonin Carême, possibly did the most to boost crème fraîche into the circles of haute cuisine. Because of its rapid spoilage, cream generally went for butter-making, ensuring a somewhat longer shelf life.
Today, in the town of Isigny-sur-Mer, located in the Norman province of Calvados, on the border of Cotentin and Bessin, the crème fraiche produced there now bears an Appellation d’Origine Contrôlée, granted in 1986.
Lactic-acid fermentation aids in the coagulation of casein proteins in cream; bacteria of the Lactococcus and Leuconostoc species produce the lactic acid which then works on the protein. That’s why the cream doesn’t curdle in the presence of heat or acid – the bacteria have made the protein unavailable for chemical reactions due to heat or acid.
Cooks and chefs utilize crème fraîche in a number of ways, but one of the most functional uses concerns sauce-making, one of the pillars of French cooking, THE pillar in the opinions of many. The thickened, fermented cream does not curdle even in the presence of acid or when added to hot soups, leaving sauces such as Bonne Femme, Breton, Normande, Poulette, Princesse, Rémoulade, and Suprême smooth as glass.
(528). Princess Sauce (Sauce A La Princesse), from Charles Ranhofer’s The Epicurean (1893)
Put one pint of bechamel (No. 409) into a saucepan, adding to it two tablespoonfuls of chicken glaze (No. 398), one gill of cream, and some grated nutmeg; stir in just when ready to serve, four ounces of fresh butter, a teaspoonful of chopped parsley, and the juice of one lemon.
Note: If you try to make crème fraîche at home, as Julia Child suggested, be sure you use buttermilk with live cultures. The proportions are about 2 T. buttermilk to 1 cup heavy cream. Mix in a glass jar. Leave, covered, at room temperature until thickened, about 8 – 24 hours, depending on room temerature. Keeps refrigerated for about a week. Addendum: I need to mention that it’s possible to use regular buttermilk, though it doesn’t get quite as thick. Speed up the process by leaving the mixture uncovered at room temperature for an hour, let it sit for about 6 hours covered, and then stick it an oven heated to about 100 F and then turned off – I use the bread-proofing feature on my wall ovens. I leave it in there for about an hour and it tends to solidify quite nicely. After that, it goes in the fridge.
© 2011 C. Bertelsen