Wool Flannel

Flannel is a wool (sometimes wool-blend) fabric that's been lightly brushed to raise a soft nap on the surface, which mutes the weave underneath and gives it that characteristic matte, slightly fuzzy look. It comes in weights from suiting-light to overcoat-heavy — the lighter weights are what you want for a skirt or a bodice.

I love it for anything that needs structure with a bit of give. It presses beautifully — darts and seams press flat and stay flat, which is more than I can say for a lot of synthetics — and it drapes with real weight rather than looking stiff. The brushed nap does mean it sheds fibers when you cut it, so I cut it on a surface I don't mind vacuuming afterward, and it shows shine if you press it directly with a hot iron. A press cloth is non-negotiable.

It's a genuinely nice fabric to learn tailoring basics on, precisely because it's forgiving of a slightly imperfect dart — the nap disguises small unevenness that would show up starkly on a smooth cotton.