Source: Tony Babinec (tony@spss.com) Issue #833, 2/28/92
Malts can be U.S. or continental, including a fraction of wheat malt if desired. Hopping should be continental noble hops. The yeast is the tricky part, as to my knowledge there is no available Kolsch yeast. The Goose Island Brewery in Chicago brews a Kolsch using a Kolsch yeast from Germany. The Free State Brewery in Lawrence, Kansas, brews a Kolsch using Wyeast "European" ale. This yeast is suggested by Fred Eckhardt. I've used the yeast from time to time and think it's a great yeast, so use this in preference to any generic ale yeast.
Following Fred Eckhardt's description of Widmer's mash sequence, mash in at 122 degrees F and hold for 30 to 45 minutes, and then raise to 158 degrees F for starch conversion. Following conversion, raise to 170 degrees F for mash out and hold for 10 minutes.
Primary fermentation should be done in the mid-60s. This beer benefits from cold-conditioning, so rack to secondary and "lager" at 40 degrees for a couple weeks.