I just use water to clean my brew kettle after brew sessions. Using an old dish rag and some warm water I am able to get a lot of the crud off the rim and most of the caramelized malt off the bottom. Persistence is the key for me though. I like to run about half a gallon of warm water in the bottom after I’ve rinsed it out as best I can, then use that to wipe and wipe the crud off where the foam rode.

By the time I’ve got all the crud off the sides and top rim and outside the browned stuff on the bottom is soft enough to scrub away. I vaguely recall using a metal scrub thing years ago on my first four gallon brew kettle and having wort char and stick to the bottom of that over and over batch after batch. It was very frustrating.

My five gallon kettle has close to fifty or sixty batches through it and no sign of beerstone around the top. Maybe I have to brew a few hundred before I start to see that.

I’ve never used soap in the brew kettle though. I probably read some where when I first started that it will adversely affect the resulting beer and subsequently have convinced myself that soap is evil incarnate for beer. Besides, why use anything else when good ol’ water works just as well?

Cheers!