Kettle washing

[Geoff Logan]

Maybe I have OCD but I can't stand it if my kettle is not clean before I brew. However, I've gone to many breweries and their kettles are pretty dirty to no ill effect. They simply clean once every week to 2 weeks. What's the consensus here? Am I wasting my time cleaning the kettle every time?

[Sulfur]

I recommend cleaning the kettle after every brew or series of brews. This was discussed in another post. Basically, if I brew once in one week, I will clean the day after the brew. If I brew 4 times in one week, I will clean on the 5th day. To leave it dirty and out of use seems like an open invitation. Also, what you may be seeing in other kettles is not dirt, but oxidation if not stainless. If you have a stainless steel, steam jacketed kettle then you can make it shine. Otherwise I think it normal to have some discoloration. I'd imagine a direct fired kettle will also look "dirty" even when clean although I've never brewed on one so I'm not sure.

[gitchegumee]

I've burnt rice to black carboniferous slag on the bottom of my direct-fired kettle before. After a day of serious scraping, wire-brushing, and a pile of green scrubbies, my kettle now shines after each and every brew. I don't do multiple brews in one day, however. At another brewery, I did. There I would CIP once a day after all beers were finished. And I do recall a thread about this posted somewhere.

[Moonlight]

I have come to believe that hop oils remaining on the kettle walls oxidize and give a (perhaps very minimal) rancid oil character to the beer. I can't say I can pick it out in finished beer, but especially as the beer matures, I believe I can taste the difference between a clean kettle and not. Could be all in my head, but I have returned to seriously scrubbing between each brewday.

I also notice improved heat transfer and boil if the heating surface is free of protein and mineral scale. More difference than I would expect just looking at it. Likely similar to the heat transfer loss when a heat exchanger is fouled...another place I have learned not to cut corners thoroughly cleaning.