What are Sieve used for? - qa.answers.com
A sieve, or sifter, separates wanted elements from unwanted material using a woven screen such as a mesh or net.However, in cooking, especially with flour, a sifter is used to aerate the substance, among other things. A strainer is a type of sieve typically used to separate a solid from a liquid. The word "sift" derives from sieve.