A Chinese food ingredient less known in the Western world is the yam (Dioscorea polystachya) literally called ‘mountain medicine’ (shanyao) in Chinese. It is sometimes called Chinese potato or by its Japanese name nagaimo. Eating Chinese yam (first scrape off the hairy peel) by itself is an acquired taste. They have a slightly hot flavour, different from the heat of chili peppers.
China has produced 48,189,000 mt of yams in 2019; good for 65.37% of the total global production. The name ‘Chinese yam’ is well deserved. The Chinese yam’s growing cycle spans approximately one year, and should be planted between winter and spring. The traditional methods growing it are: using smaller tubers, top cut of bigger tubers or through cuttings of branches. The first two methods can produce 20 cm long tubers and above. The latter produces smaller tubers (10 cm) that are usually replanted for the next year. Between 7 and 9 months of replanting Chinese yam tubers, their leaves start to get dry, which indicates that it’s time to harvest. In home gardens generally only what will be consumed is harvested, with the rest left in the pot in moist soil.
Chinese yam is also a herb in Traditional Chinese Medicine. The main health benefits it is known for is strengthening the spleen and stomach to aid digestion. Chinese yam also aids in lowering the blood sugar level. It can be used to treat diabetes or a good diabetic diet. Besides that, Chinese yam contains mild medicinal properties, unlike ginseng which could help to regulate sleep. Consuming Chinese yam helps to nourish kidneys and enriching essence as it contains a variety of nutrients which can strengthen the immune system of the body.
Study shows that Chinese yam has antioxidant properties which is beneficial as a daily supplement. Chinese yam extract helps in preventing disease which plaque build-up in the arteries. Chinese yam also is a natural slimming food. It has high fibre content to produce the feeling of fullness after consuming it.
Yam in cooking
Unlike most other yams, the Chinese yam can be eaten raw (grated or sliced). However, Chinese still usually cook yams, as they are much less interested in eating raw food than their eastern neighbours in Korea and Japan. To prepare fresh Chinese yams, it is recommended to rinse it under cool water before peeling the outer skin. Take caution while peeling as the slipper secretion makes it difficult to grip. Do not soak Chinese yams as it weakens the beneficial functions of the herb and washes the nutrients away.
The most common way to consume Chinese yams is cooking chunks of yam in rice congee. The yam adds texture to the congee, while the congee helps neutralising the sharpness of the yam. Dates are often added for their fruity sweet flavour.
Chinese yam can also be stir-fried alone with carrots, hot peppers dipped in hot pot or stewed pork rib soup.
Peter Peverelli is active in and with China since 1975 and regularly travels to the remotest corners of that vast nation. He is a co-author of a major book introducing the cultural drivers behind China’s economic success.