Using different yarn as specified in pattern

[ButterflyBlue]

I'm new to crocheting and have found an easy bag pattern that I'd like to try. The recommended yarn is 4ply mercerised cotton can I use 4 ply wool instead.

[RochesterKnitter]

As far as weight goes, yes.

You need to check the gauge so that you get the intended size of bag.

You need to be more concerend about the qualities that cotton offers versus wool. Cotton won't stretch (inelastic plant fiber), which is desirable in a bag that is intended to hold heavier things. And, you can wash cotton more easily. If you wash you wool bag it will felt. So, is this bag something that will be getting dirty (like a market bag) or something that will stay fairly clean ( like a yarn/project bag in your house)?