Repeat after me. I do not prewash flannel when it is the only fabric in a rag quilt. I make rag quilts and they come out great without a prewashing. If I were to use flannel as just as backing, then yes I would prob prewash.[/quote]
Ditto to this post. I am making a log cabin star quilt from flannel, top and backing both flannel and batting will probably be wool. I am not prewashing either, but I have a friend who made a gorgeous quilt and backed with flannel that she DID prewash. In her family it is the quilt of choice to cuddle under and has been washed now many times. Looks great.