K is for Kraeusen
It’s pronounced Kroy-zen. What it refers to is the frothy foam that builds up on top of the fermenting beer, especially early in fermentation.
You can see it below in this video of my one-gallon batch of Irish red ale brewing. In this case, the kraeusen grew so thick that I had to attach a blow-off tube to let the foam out.
For top fermenting brews, like ales, yeast may be found in the kraeusen, and might be harvested for re-use.
Different strains of yeast and different brewing conditions can result in greater or lesser development of the kraeusen. It’s important to replace the regular airlock with a blow-off tube if your kraeusen is going to fill all the headspace of your fermentation vessel.
I’m participating in the April A to Z Blogging Challenge. The goal is to write a post prompted by a letter of the alphabet on each day of April (except Sunday). My theme this year is brewing. Visit my other A to Z posts by clicking here.