How do I make tempura turn out light? I've probably only made tempura 10 times in my life, with fairly inconsistent results. often it has been heavier than the best restaurant versions I've had. There seem to be many variables involved:


type(s) of flour
added pure starch (cornstarch, arrowroot, ...?)
use of seltzer
use of chemical leavening
overall thickness of batter
type of oil
temperature of oil


Which of these factors (and any others I've forgotten) are most important to getting a thin, light, non-greasy tempura shell?
Type of flour: rice
Liquid: soda (seltzer) water

Mix as little as possible. Lumps are okay. Dip quickly, drop into 350 veg/soy oil.