Caltrop Starch
By: Sheri Wetherell

About

Caltrop starch is a gray powdery starch made from water chestnuts (also known as the water caltrop). The starch is used (with other ingredients such as tang flour) in Asian cooking to make dumpling skins and is good for making crisp coatings and batters, as well as a gloss in sauces.
The starch is created by drying ground water chestnuts, which are then boiled, peeled, dried then ground into flour.

Information
Other names: Water Chestnut Starch, Water Chestnut Flour, Water Caltrop Starch
Translations: Caltrop Ciete, Vieliniai ežiai Krakmolas, Colţul-babei Amidon, Caltrop škroba, Củ ấu tinh bột, Kotewka skrobi, Zetmeel Caltrop, Caltrop स्टार्च, Caltrop Amido, Колтроп крахмала, Caltrop άμυλο, نشا احد من نباتات مختلفة, 마름쇠 전분, Kovový ježek Škrob, Caltrop Pati, Caltrop almirol, 菱角淀粉, Cards midó, Caltrop Škrob, Kovový ježko Škrob, Caltrop Amido, Caltrop עמילן, Caltrop Stärkelse, Цалтроп Скроб, ハマビシ澱粉, Châtaigne d'amidon, Caltrop Stivelse, Caltrop Stivelse, Abrojo almidón, Колтроп крохмалю, Caltrop Tärkkelys, Caltrop нишесте


Physical Description
Caltrop/water chestnut starch is indeed a starch rather than a flour.  When fried, the starch coating will remain white in color.
Colors: white to grayish 


Tasting Notes
Flavors: adds texture, muted, starchy
Mouthfeel: Fine powder, Crispy when deep friend, Glossy in liquids and sauces
Food complements: Coating for dumplings, Sauces
Substitutes: Corn and tapioca flours in equal parts, Cornstarch, Wheat flour for dredging and coating


Selecting and Buying
Seasonality: january, february, march, april, may, june, july, august, september, opctober, november, december
Buying: Caltrop starch can be found at various online retailers as well as some asian specialty markets.  The starch may be somewhat more expensive than other similar starches.
Procuring: Water Chestnuts can only be grown in semi-tropic regions due to the long frost-free period required (7 months).  They are often grown in marshes in southeast China, but they may also be found in Japan, Taiwan, Thailand, Australia and select regions of California and Florida.  Because collection of raw caltrop is considered labor intensive, a higher expense typically results.


Preparation and Use
Caltrop starch is often used as a thickener and also to add a sheen to whatever liquid it is mixed with.
First mix the powder with cool water before adding it to warm sauces that require thickening.
The powder can also be used as a coating similar to corn starch when frying; this will add a crispy texture.
Cleaning: The starch shouldn't need much processing/cleaning.  Adding to a small amount of water before adding to a sauce can help.  Caltrop starch doesn't mix with water as well as cornstarch though, so it may take some mixing.


Conserving and Storing
The starch can be stored 6-12 months in a room-temperature, sealed container


Social/Political

History: Caltrop starch has been used for centuries in regions such as southeast China.