Definition
Sour cream (also known as soured cream in British English) is a cultured dairy product obtained by fermenting regular cream with specific strains of lactic‑acid bacteria. The bacterial culture lowers the pH, causing the cream to thicken and develop a tangy flavor characteristic of lactic acid production.
Production process
Traditional sour cream is made by allowing cream skimmed from milk to ferment at moderate temperature, either by inoculating pasteurised cream with a starter culture or by natural bacterial contamination. Commercial production standardises the milk‑fat content (typically ≥ 18 % in the base cream, ≥ 14.4 % in the finished product) and may add stabilisers, bulking agents, or thickeners such as gelatin, carrageenan, locust‑bean gum, or starch to achieve consistent texture and shelf life. The product is not fully fermented; it requires refrigeration both before and after opening.
Regulatory standards
- United States (FDA): Minimum 18 % milk fat in the base cream, at least 14.4 % milk fat in the final product, and a total acidity of ≥ 0.5 %.
- Canada: Allows specific emulsifying, gelling, and stabilising agents (e.g., algin, carob bean gum, carrageenan, pectin, monoglycerides) within defined limits; also permits certain milk‑coagulating enzymes derived from microbial cultures.
Physical and chemical properties
Sour cream typically contains 0.5–1 % lactic acid, giving it a pH around 4.5–4.7. Its viscosity and smooth texture result from the combined effects of fat globules, protein coagulation, and any added thickeners. The product is a colloidal emulsion of fat droplets dispersed in a water‑protein matrix.
Culinary uses
Sour cream is a versatile ingredient in many cuisines. It is used as a topping for dishes such as chili, baked potatoes, and tacos; as a component of dips, dressings, and sauces; and as a moisture‑enhancing element in baked goods, casseroles, and frostings. In Eastern European cooking, it is often served with pierogi, blini, and soups. The related product crème fraîche has a higher fat content and milder flavor, making it suitable for hot applications without curdling.
Nutritional profile
A typical 100 g serving of commercial sour cream provides approximately:
- Energy: 190–210 kcal
- Protein: 2–3 g
- Fat: 18–20 g (mostly saturated)
- Carbohydrate: 3–4 g (primarily lactose)
- Calcium: 80–100 mg
It also supplies vitamins A and D, though its high saturated‑fat content makes moderation advisable in diets concerned with cardiovascular health.
Storage and shelf life
Unopened sour cream should be kept refrigerated and can remain viable for 1–2 weeks beyond its printed “sell‑by” date. Once opened, it generally retains acceptable quality for 7–10 days under continuous refrigeration. The product must be stored at temperatures ≤ 4 °C to inhibit spoilage and pathogenic bacterial growth.
History
Fermented cream has been consumed in Central and Eastern Europe for centuries, with early records indicating its use as a preservation method before widespread refrigeration. Commercial production expanded in the United States during the early 20th century, coinciding with the development of standardized bacterial starter cultures.
See also
- Crème fraîche
- Yogurt
- Buttermilk
- Fermented dairy products
This entry is compiled from established encyclopedic sources, including the Encyclopaedia Britannica and peer‑reviewed food science references.
