kiwine said: Ahem... French wine bottles are made to be holden like this: the bottom of the bottle is concave so fingers can go in. It's the way cellarmen do it.
Right, ancient comment I know, but that's not the most plausible explanation for it. The most commonly understood explanation for the presence of punt in the wine bottle is that it was production necessity, and could stand up better. The bottle design has been copied and carried on to the rest of the world, so it's not just French.