So my question remains: what causes the specific twine directions of different bine species?
I didn't think a talk about Hamilton, Tait, Maxwell, and the history of vectors would lead me to such questions.
So a quick search reveals that it is indeed true.
Hops are a type of bine and even within bines:
some bines always twine clockwise, including runner bean (Phaseolus coccineus) and bindweed (Convolvulus species), while others twine anticlockwise, including French bean (Phaseolus vulgaris) and climbing honeysuckles (Lonicera species).
So it is species-specific amongst bines. There is even apparently a Flanders and Swann song about the difference.
I have no idea if it's true but, if so:
a) there's a cute distinction one can then draw between wine and beer :-)
but more fascinating:
b) what controls this? is it heritable? are there mutations? can you breed left-handed vines and right-handed hop plants?
Beardon explains that the tendrils of a vine grow in a right-handed manner and the tendrils of a hop plant in a left-handed manner.
In a letter about the mathematical Society ruling, Maxwell says to Tait:
Finally, I thank you and praise you from the system of the hop to that of the vine. I have perverted the whole of electromagnetics to suit.
It's basically the equivalent of saying "I've asked about the coding conventions and have updated my code to confirm" :-)
But what is this system of the hop versus system of the vine?
Maxwell apparently asked the London Mathematical Society to make a definitive ruling, which they did on 11th May 1871 in favour of the right-handed rule.
It in, around the 45 minute mark, he is talking about how, by 1870, the world was basically split as to whether to adopt a right-handed or left-handed rule for the third axis.
There's a wonderful talk by Alan Beardon on the history of vectors.