Pickled cassava leaves is fermented food made by preserving crumpled young cassava leaves in brine water. This preserved food can be served as a side dish, or cooked as a stir fry dish, or can be used as a source of acidity in Vietnamese sour soup (canh chua) pairing with a variety of local fish. Pickled cassava leaves has some common sour taste, a little bitterness, and nutty taste.
The cassava (Manihot esculenta, Vietnamese: North: sắn, South: khoai mì) is one of the most drought-tolerant crops, can be successfully grown on marginal soils, and gives reasonable yields where many other crops do not grow well. Using cassava leaves as a leafy vegetable is best known in Phú Thọ province where the ethnic Mường people live. Pickled cassava leaves also exist in the cuisine of several other ethnic people who live sparsely in mountainous regions in northwestern Vietnam such as the Cao Lan people.
In Vietnam, there are several varieties (or subspecies) but such genetic studies are not thoroughly done. Notably, there are white cassava (with green leaves and white petioles) and red cassava (with red petioles). According to the cooking practice of the local people, they only choose the white cassava variety. It is also noted that a Manihot species or cassava variety with narrow purplish leaves (Vietnamese: sắn lá tre) is not used because the high level of toxicity. Also, the bitter cassava (Manihot utilissima, Vietnamese: sắn dù) is also not advised for the same reason. However, now there are many new cassava cultivars, so it’s quite difficult to differentiate one from another. The general rule is only choose the species or variety/cultivar with a low level of toxicity.
The best leaf parts are the stout young cassava buds that still have some fine powder on the top of the buds.
Cassava leaves must be pickled and should not be consumed raw.