In Eric Warner’s Koelsch he has a table of fermentation byproducts of Koelsch yeast, Weizen yeast, Alt yeast and Lager yeast.
The Alt yeast produced more Iso-amyl acetate (banana esters) than the Weizen yeast. The lager produced more ethyl caprate/caproate/caprylate (fruity/winy) than any of the other strains. The Koelsch strain produced less higher aliphatic alcohols (fusel/solvent) than any of the other yeasts.
Just going by the numbers it seems his Koelsch strain was “cleaner” than whatever lager strain he used, which is not what I would expect. I drank a Reissdorf Koelsch recently, and I didn’t pick up any vinous character. If I didn’t know better, I would’ve called it a typical German lager. So, I don’t really know what to think.
Did he mention what temp he fermented them all at? That’s an interesting finding, but unless they were each fermented in their normal temp range, those results may not extrapolate well to everyday use.
He says they were all fermented isothermally at 59*F. I guess that makes sense about the lager yeast. I’ve heard they get fruitier at higher temps. Still, for the other yeasts, that’s a “typical” fermentation temp, and it’s surprising the Alt yeast threw more banana esters than the Weizen yeast.
Reissdorf kolsch is not the best kolsch to compare what you will find in cologne or what you may brew at home. For one thing it is probably past its prime by the time you get it home to drink it. I’ve never been a big fan of it, not terrible, but not terribly good, either./
The results were from his Wheat book, and those results were taken from F. Nitzsche, Analysenergebnisse der Weizenbiere des DLG Jahres 1988, excerpt from dissertation, Technologie der Brauerei I, Freising, Germany, 1990. So, unless someone has a copy of that I’m not sure what strains he’s talking about.
I’ve made a lot of what I think are Koelsch, using what Wyeast calls “Koelsch yeast,” but I’ve never had any commercial Koelsch that taste anything at all like what I make at home.
I am able to get Sunner Kolsch as the only import of it’s style. Think I can do better at home since it obviously hasn’t traveled well but was still clean with a light fruity faint character. I have only used the White Labs yeast.
Served in a blind test most uninitiated drinkers would probably peg a kolsch as a lager especially if it is hopped lightly.