[paul.fr]

Well, im still smoking and to make matters worse i've lost my lighter. So, whilst using matches i noticed that as they burn every match curled upwards! Why? Just to add, i've cut down 50%.

[daveshorts]

I think the reason is that the charcoal goes through some sort of solidification process, and shrinks as it cools, the bottom half of the match shrinks first, and is stretched by the top half so it solidifies slightly long. As the top half then shrinks it bends the match upwards.