Cold Filtering to remove proteins

[I-GOR]

O.k. I don't normally subscribe to wine expectorator mazagine, but Feb issue cover was all about American Whiskey report.

Page 62 was article about makin whiskey the american way.

"Step 8: Bottling
The whiskey is screened to take out chunks of char, then chill-filtered to remove proteins that could cause a harmless cloudiness in the bottle. Then it is cut with water to bottling proof - reguslation requires a minimum of 80 proof and forbid any addition of colro or flavor- and packaged."

Could any of you fine gents elucidate on the topic of chill filtering to remove proteins? I normally run it through a handfull of coffee paper fileters. Question is, any advantage to sticking it in the freezer overnigth and then filtering'? and, what are the "proteins" to be removed?

thanks for your input.
I-gor