sour cream
A thick, tangy dairy product made by fermenting cream with bacterial cultures, used as a topping, a base for dips, and to add richness and tang to baking and sauces. Its fat content makes it more stable under heat than thinner dairy products, though it can still curdle if boiled hard or hit with too much acid too fast.
Buying guidance
Check the fat percentage where it matters -- full-fat sour cream holds up much better in hot sauces than light or fat-free versions, which are more prone to breaking. Choose a cold, sealed tub with no swelling or off odor.
Substitutions
- Greek yogurt -- similar tang and thickness, but leaner and more likely to curdle over high heat, so stir it in gently or off the heat.
- Creme fraiche -- richer, less tangy, and more heat-stable, making it a good swap specifically for hot sauces.
- Mexican crema -- thinner and milder, closer to pourable than spoonable, better as a finishing drizzle than as a thickener.
Tips & common mistakes
Stirring cold sour cream directly into a hot pot is a common way to curdle it -- whisk a spoonful or two of the hot liquid into the sour cream first to warm it gradually, then stir that mixture back into the pot off the heat or over low heat, which keeps it smooth.
Storage
A thin layer of liquid pooling on top of an opened tub is just separated whey, not a sign of spoilage -- pour it off or stir it back in. Sour cream doesn't freeze well on its own, since the fat and water separate as it thaws into a grainy, watery texture that's fine stirred into a cooked sauce but won't work again as a smooth topping.