Moonshiners let the first bit of 'shine "pass", i.e., pour it off for a bit before bottling the rest.

Means the fluids that condense before the alcohol (lower boiling point) are gotten rid off.

If you discarded everything that boiled off before 100 C, and everything that boiled off afterwards, you should have pure water <img src="/images/graemlins/smile.gif" alt="" />

Your mileage may vary.
_________________________
Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein