Why we weave in muslin

Muslin is an open, loosely woven cotton. It looks thin, and that is exactly why it works: air moves through it, so it dries between uses instead of staying damp.

Why four layers

A single layer of muslin holds very little. Four layers hold a feed and still dry by the next one, which is the balance the whole cloth is built around.

Terry holds more per layer and gives it back more slowly. That is fine for a bath towel and wrong for something that goes over a shoulder eight times a day.

The tenth wash

New muslin feels stiff and slightly papery. It softens with every wash for roughly ten cycles and then stops changing. Judging a cloth on the first day is judging it at its worst.

This is also why fabric softener is a mistake here. It coats the weave, and a coated muslin stops absorbing, which is the one thing you bought it for.

Sizes and what they are for

The large square, around forty-seven inches, is the one that does everything: a cover, a mat on somebody else’s carpet, a shade over a stroller. Four to six of those covers most households. Burp cloths are separate and counted separately, because they get used far harder.