Mark Thorson wrote:

A few years ago, when I researched this on the web,
it quickly became apparent from reports of hobbyist
applejack-makers that you don't get a very good
result. It concentrates the alcohol, but it also
concentrates the fusel oil. Distillation gives you
a much higher quality product.

I have read similar comments. The problem is the
methol alcohol and proper distillation protocol
eliminates it. But keep in mind that most alcohols
get their flavor from the barrels in which they are
aged

Eisbock is a freeze distillation bock beer. The
comments I have read on it consistent suggest
skimming the ice chips of the top every day or two
as opposed to letting chunks form. But I've never
read the science behind that.

Dick