an example of a dairy product in motion; its use has been steadily spreading westwards. It is a traditional and important ingredient in Russian, E. European, German, and C. European cooking, both in savoury and in sweet dishes. In the second half of the 20th century, however, it has started to become a staple in the western parts of Europe, N. America, and elsewhere.
The attractive sour (perhaps better termed acid) taste offsets the richness of the cream which might otherwise be cloying. Sour cream is thicker than fresh cream of the same fat content. This is a result of partial coagulation brought about by the acid created during the souring process.
Russian smetana and Polish smietana are often taken by translators to be ‘sour cream’, although the dictionaries give the meaning of the words simply as ‘cream’. In fact smetana and smietana are mixtures of sour and fresh cream, and have a milder taste than sour cream alone.
Traditionally, sour cream was made by letting fresh cream sour naturally. Lactic (and to a small extent, acetic) acid-producing bacteria in the cream could normally be relied upon to give an acceptable taste. It was always a mixture of species that did the work: Streptococcus and Leuconostoc species producing a little acid and some diacetyl, a substance which gives a pleasant buttery flavour, while various species of Lactobacillus made a greater amount of acid. However, occasionally some unwanted micro-organism would grow and give an off flavour. Smetana had to be made immediately before use, since it took only a few hours for the bacteria in the sour cream to sour the fresh cream completely.
Modern cultured sour cream is made by pasteurizing and homogenizing light (English ‘single’) cream and inoculating it with a pure culture of selected bacteria. The cream is kept fairly warm to favour their growth until it is sour and thick enough, then repasteurized to stop the process. It is therefore ‘dead’ when sold, and cannot be used as a starter. Sour cream of whatever type must not be boiled in cooking, or its partly coagulated custard-like texture will be overtaken by complete coagulation and it will curdle. Nor can it be whipped. Otherwise, it has a wide variety of uses, amply demonstrated in the cuisines of E. and C. Europe.
Römme, a Norwegian sour cream, is made into römmegröt, a cream-enriched porridge.
Alan Davidson was a distinguished author and publisher, and one of the world's best-known writers on fish and fish cookery. In 1975 he retired early from the diplomatic service—after serving in, among other places, Washington, Egypt, Tunisia, and Laos, where he was British Ambassador—to pursue a fruitful second career as a food historian and food writer extraordinaire. Among his popular books are Seafood of South-East Asia, North Atlantic Seafood, and Mediterranean Seafood. In 2003, shortly before his death, he was awarded the Erasmus Prize for his contribution to European culture.
