Katakuriko & kuzuko / potato starch & arrowroot starch

Katakuriko / potato starch

Originally made of the lily-family plant katakuri (Erythronium japonicum, Japanese trout lily), katakuriko in the market today is mostly made of potato starch due to the rarity of the plant.

When using it as a thickener, mix one part katakuriko to one to two parts cold water.

For tempura, adding potato starch to batter (2-3 parts potato starch and 7-8 parts flour) gives a crispier and lighter texture.

Potato starch is also used as a coating for deep-fry (ingredients can be seasoned or not seasoned).

When preparing shelled prawns or oysters, rubbing potato starch and rinsing with water help clean them, remove the smell and make them plump.
(See how potato starch cleans prawns and oysters.) 

Kuzuko / arrowroot starch

Can be used in the same way as katakuriko potato starch as a thickener, but unlike potato starch, arrowroot starch warms your body and is sometimes used for therapeutic purposes, such as when having a cold.

Because it is much more expensive than potato starch, kuzuko is mainly used for special dishes. It is also a main ingredient in traditional Japanese confectioneries.

Yoshino in Nara Prefecture is known for producing high-quality arrowroot starch.