On Cleaning the Boil Pot

Last Monday I had the wonderful opportunity to help brew a batch of beer at the Goose Island Brewpub here in Chicago. This was to be a collaboration brew between Goose Island and the Chicago Beer Society. The beer is a recipe by Randy Mosher for a spiced Belgian Wit called Partial Eclipse. There were a number of us helping, which basically meant we did a lot of cleaning while guys like head-brewer Jared, Randy, and Ray Daniels took care of the recipe and managing the brew process.

Anyways, of the many things I learned (and cleaned), the one that I took immediate notice of was the boil kettle - mostly because I found myself getting inside it (a tricky climb through the top port - thank you yoga!) and scrubbing while holding onto a flashlight in the other hand (very dark in there!), and trying not to hit my head/rack myself on various steel tubing. Here's me in the kettle:

The first thing that struck me was, dang - even dirty this thing is cleaner than my boil kettle! So I just set about cleaning it best I could before hosing everything down. Well, after assistant brewer Todd checked my work, he climbed in and scrubbed out a spot I missed around the drain pipe - damn! He then filled the bottom with an acid-based caustic solution, let it sit awhile, and pumped it through the plumbing. So anyways, that got me wondering....

Just How Clean Should My Kettle Be?
I posed this question to both Randy and Rodney Kibzey (Sam Adams Longshot Winner). They both recommend keeping your pots good and clean, free of both gunk and beerstone because it helps minimize any off-flavors, saves your pot from pitting, keeps the heat dispersal even, and general peace of mind. On the other hand, I've heard guys say the dirtier the pot, the better the beer - like seasoning a cask iron skillet. Post boil I've been scrubbing down with dish soap and a kitchen scrubbie-sponge, getting most, but not all, the gunk off, and then spraying the pot down with some StarSan, which is acid-based and good for the steel. I started doing this less-than-polished type of cleaning after a metallic taste appeared in one of my batches.

So the next day I decided to try properly cleaning my pot. I gave the entire thing a good 1 hour soak in PBW (1oz per gallon), scrubbing with a brush. I also opened/closed the ball valve a few quick times before and after the soak, trying to loosen any gunk in there. After an hour I gotta say the water was a gross, murky brown - and some of that gross murky brown stuff was probably getting into my boiling wort SCREW THAT! I drained it through the ball valve, hoping to flush any more crap outta there. Makes me think about investing in a 3 piece valve I can take apart and clean.

The PBW took away most everything, except there was some white stuff at the bottom that wouldn't scrub off - I took this to be some hardcore beerstone or maybe a limestone-like substance, either of which can harbor microorganisms and damage the steel underneath it. There was also some particularly stubborn, brownish beerstone along the sides still. From an article on byo.com:

Bio-fouling (trub deposits) and beerstone scale (calcium oxylate) can also cause corrosion. The metal underneath the deposit can become oxygen depleted via biological or chemical action and lose passivity, becoming pitted. A two step procedure is most effective for removing beerstone. Beerstone is a combination of protein buildup and mineral deposit, so removal works best if the protein is broken up with a caustic, like sodium hydroxide or PBW, and then the remaining lime can be dissolved by an acidic cleaner like CLR (Calcium Lime Rust Remover).

Off course you can say we're killing all those nasties during the boil, but if we're going to be clean let's be clean, and keep our kettle in good shape while we're at it. So after the PBW soak I did a splash of warm water, and an equal splash of CLR, and a sponge-wipe, and it was gone just like that. Rinse with some cold water, and wow - like new! A quick spray with some StarSan, and it's good for storage. Now my kettle is as clean as I can make it - looks good, and ready for my next batch :)