Small fibers or a rough surface after the first wash

This is called grain raising, and it's normal for natural acacia wood. It's a surface fiber effect, not a safety issue and not a defect.

1. Let the board dry completely.
2. Pass a fine sandpaper, 200 to 220 grit, lightly over the surface.
3. Recondition it with a food-grade oil or beeswax.

Regular oiling keeps the surface smooth from then on.