I use a recipe that was given a gold award. I was instructed that by using only German pilsener malt, and Wyeast 2565, you will make an excellent kolsch style beer. Mash for at least 60 minutes if not longer at 149*. Ferment from high 50's to low 60's with this yeast, then lager (cold condition) as you would with a lager. You will need a huge starter, I make a 4l starter for 11 gallons.
It is said that only one or a few breweries in Koln (Cologne) use any wheat at all. The German pils, by itself, will give an adequate head.
It is said to boil for 90 minutes to alleviate DMS precursors, with pils malt.