Molecular Sieve Distilling

[dr wacky]

When distilling ethanol for use in making biodiesel or E85, I know it has
to be very dry(199-200 proof). Filtering your high-proof distilate through
a molecular sieve will accomplish this drying effect. Now here comes the
stupid question. If you read any further and are offended at my ignorance,
you were warned.

What would stop a fellow from just filtering his whole wash through a
molecular sieve to achieve ethanol separation? I can see a couple of
drawbacks to this idea. You would have to sieve many times to achieve
any purity(10, 15, 20 ). Seems it would depend on the alcohol content of
the wash, volume of wash, and size of the sieve. You would also have no
way to make 'cuts'. But in a fuel application, that really shouldn't matter.

This isn't how I plan to do my real distilling, but I may experiment with
a small test batch or two just to see if it's possible. Anyone willing to point
out a glaring oversight in this process?