Why do we need to sift ingredients
Sifting ingredients like flour, icing sugar, etc incorporates air into the item in question. For example, when making airy batters, like sponge cake and Genoise, by sifting the flour with the baking powder prevents the mixture from having lumps, which makes it easier to mix with other raw ingredients.
There are various sifters you can use, which all comes down to preference, depending what you do, as shown below;
All sifters should not have the same mesh size. For example, flour would require a finer mesh size while almond meal requires a coarser mesh size.
If you are sifting wet ingrediens, like fruit purees or certain types of creams, you may use a spatula to scrape the product through, leaving unwanted lumps behind.
It would be best to sift a dry ingredient BEFORE weighing it, because the ingredient might weigh less after sifting it, due to the fact that some of the ingredient is lost during sifting.
Flour, icing sugar, nut powders, and cocoa are popular ingredients that are usually sifted. Flour is sifted when making delicate batters (eg; genoise, lady fingers), almond powder is sifted when making macarons, cocoa is sifted when making chocolate sponge cake, etc...
We usually do NOT rinse the sifter after use, because we always sift the same ingredient (eg; flour). We simply cover the sifter in a large bowl and set aside until needed. If you do wash a sifter and you do not thoroughly dry it immediately, it will rust in a few days.