.5 lb sour cream

Sour cream is a fermented dairy product made by the bacterial acidification of regular cow's milk cream, typically containing 18-20% milk fat. The lactic acid bacteria (primarily Lactobacillus lactis) naturally present in the cream or deliberately introduced as a culture ferment the lactose, lowering the pH and creating the characteristic tangy flavor and thick, spoonable consistency. The fermentation process typically takes 12-24 hours at controlled temperatures. Sour cream originated in Eastern Europe, where cooler climates naturally encouraged spontaneous fermentation of cream, and has since become a staple in American, Central European, and Russian cuisines.

Sour cream functions both as a condiment and as a cooking ingredient across numerous culinary traditions. It is commonly served as a topping for baked potatoes, tacos, borscht, and baked goods, and is essential in Russian and Eastern European cuisines for dishes such as stroganoff, pelmeni, and sour cream cakes. In baking, sour cream adds moisture and tenderness to cakes, muffins, and quick breads while contributing subtle tang. It is also used in marinades, salad dressings, dips, and sauces where its acidity and richness enhance other flavors. When cooking with sour cream, it should typically be added near the end of heating to prevent curdling, though it can be stabilized with a slurry of cornstarch and liquid.