Tempeh is a fermented food made from soybeans, most popular in Indonesia and other parts of Southeast Asia . Tempeh is unique among major traditional soyfoods in that it is the only one that did not originate in China or Japan . It originated in today's Indonesia, almost certainly in Central or East Java, almost certainly prior to 1800, and perhaps as long ago as a thousand years or more.

Tempeh

To make tempeh, cooked and dehulled soybean cotyledons (which may be lightly acidified with a traditional lactic acid prefermentation or, nowadays, with lactic acid or vinegar) are well drained then inoculated with spores of the Rhizopus oligosporus mould, packed into perforated containers (polyethylene bags or traditional banana leaves,) and incubated at 30-31°C for about 24 hours, until the beans are bound together tightly by the mycelium. The tempeh is then ready to sell or to cook.

Tempeh in an Indonesian village market

As a result of the fermentation process the soy bean protein becomes much more digestible. In particular, the oligosaccharides that are associated with gas and indigestion are greatly reduced by the Rhizopus culture (see here). In traditional tempeh making shops, the starter culture often contains other fungi or bacteria originating from the natural starter, traditionally Hibiscus leaves (named usar). In western countries, it is more common to use a pure culture containing only Rhizopus oligosporus. Specialty tempehs may be made from other types of beans, or may include a mixture of beans and whole grains.

Traditional starter (usar) with Rhizopus mould.

In the kitchen, tempeh is often prepared by cutting it into pieces, soaking in brine or salty sauce, and then frying. Cooked tempeh can be eaten alone, or used in chili, soups and stews. Tempeh has a complex flavuor that has been described as nutty, meaty, and mushroom-like. Tempeh freezes well, but should not be kept more than a few days in the refrigerator. Spoilage can easily be observed by black decolouration (sporulation) of the product.

In Indonesia, traditionally and in dictionaries since at least 1875, the name for this food was written témpé, with various accents being used. Soy tempeh was called témpé kedelé. In August 1972, when Indonesia modernized its language the accents were dropped and the word came to be spelled tempe . In English and other European languages, the word has come to be spelled "tempeh," the final "h" being added to prevent the word from being pronounced "temp." The first Westerner to use the spelling tempeh was the Dutchman H.C Prinsen Geerligs in an 1896 German article about soyfoods. But other early Western authors wrote the word as témpé or tèmpé. Since the early 1960s, the word has consistently been spelled tempeh in European languages.