The color of a finished dish is often important, either for its symbolism or because it simply looks appealing. For example, nut-based recipes often call for the nuts to be blanched, or skinned, as a preliminary step. You can buy them already blanched, but it's not necessary. It takes just minutes to blanch whole, skin-on almonds, so there's no need to keep more than one kind in your pantry.
Removing the skins serves a couple of purposes. Cosmetically, removing the brown skins lets the nuts' own pale color show through -- the very word "blanch" comes from the French word for white -- which lends your finished dish a clean appearance. The skins also contain natural tannins, which can lend a hint of bitterness to your nut-based treats.
How to Blanch
The process itself couldn't be easier.
Pour the skin-on almonds into a heatproof measuring cup or mixing bowl.
Heat some water -- enough to cover the nuts completely -- until it's just on the verge of boiling. Pour the water over the nuts and let them sit for 2 minutes.
Drain the nuts in a colander or strainer and rinse them briefly with cold water to cool them down.
Pick up the nuts one at a time, once they're cool enough to handle, and hold them over a second bowl. Pinch each nut gently between your thumb and forefinger, and it will slide easily out of its skin.
Dry the nuts before using them, either by blotting them on a clean towel or letting them air-dry on a paper-lined baking sheet.
It isn't strictly necessary to hold the almonds over a bowl as you skin them. You could do it over a sheet pan instead, for example, but the nuts sometimes pop out of their skins with surprising speed and skitter away from you. Chasing rogue almonds across the kitchen floor can be great fun for the kids, but it's counterproductive.