pitching on to an previous bed

I am thinking about brewing a kolsh and bottling and brewing an american hefe same day and putting it on the yeast bed from the kolsh. I have heard of this being done before but have never done it. Thoughts?

You can certainly do that.  It’s easy and effective.  For a low gravity beer like a hefe, though, you’d likely be better off only using 1/3-1/2 of the slurry from the kolsch.  You can pour the rest into a sanitized container and use it another time.

you’ll probably be alright but realize that you will be over pitching by 4X the amount at least, carrying over a lot of dead yeast (which can adversely affect flavor) and your won’t be removing the braunhefe (brown yeast) which sticks to the side of the fermentor and has a lot of bitter and harsh flavors you won’t want in a lighter flavored beer like an American Wheat. I’d suggest harvesting the yeast, cleaning and sanitizing the fermentor and pitching only 1/4 - 1/3 the slurry. That will make the better beer, IMO.

Is there anything special in the process of harvesting the yeast or do I just rack the beer take the slurry?

That’s it. Rack the beer, pull ~12 ounces of the slurry into a sanitized jar, clean the bucket and proceed as normal

I’ve always racked the beer and then saved aabout 1/2 of beer in bottom to loosen slurry and then dump into a couple wide mouth sanitized jars. Don’t tighten lid all the way if saving or it will break under pressure.

edit: Mort beat me to it.

You mean 1/2" right? Not 1/2 of the beer…

yes! Thanks for the correction Jim!!! 1/2" of beer on botton.

do you keep it refrigerated?

Yep.

k thx