See also msg 14739.
Helianthus tuberosus is the botanical name for Jerusalem artichokes
(sometimes called 'sunchokes') which are a native of North America
but which appear to be under utilized for the production of vodka.
The JA contains the polysaccharide inulin instead of starch, and the
the hydrolysis of inulin yields fructose (fruit sugar), while true
insoluble starch (amylopectin) as found in potatoes yields glucose.
Therefore the character of a 90%abv vodka from JA would be different
to that from grain or potatoes.
For processing information see -
Another root crop to consider are Sweet potatoes which have nearly
30% fermentable material, and which are used in Japan for
making 'shochu' but appear to be neglected as a fermentation source
in the US and Australia.