Any ideas on how best to remove burned-on material from kettle bottom?

[Paul Parks]

I have a customer who just bought a used 15 bbl kettle with an inch of material burned onto the bottom. He is new in the business and is wilting at the prospect of what it will take to restore the kettle. Does anyone know of anything he can use to loosen or soften the burned stuff so it isn't so hard to chip off?

[Laughing Dog]

Fill the kettle with hot water and Caustic or something like Cell-R Master from Birko, let it soak and it should come loose, It may take a few applications we had a tank that had some caked on crud that I could not get off, and this method worked.

Fred Colby
Laughing Dog Brewing

[rafters_brewer]

Well, I haven't had to deal with that much burned on the bottom of a kettle, but in the past I have soaked it in hot cautic or Bar Keeper's Friend (http://www.barkeepersfriend.com/index2.htm), which you can find in the cleaning isle at most hardware stores. And then you scrub the hell out of it with steel wool.
If you want to remove the heat discoloration, I would recommend a cleaning product called Flitz Metal Polish Paste (http://www.flitz.com/) which you can sometimes find at the hardware store.
That sounds like a helluva mess, so good luck.

[Sir Brewsalot]

Just make sure to re-passivate the stainless afterward. I was using BKF for some spot cleaning and found that it dirtied up EXTRA fast afterward as a result of NOT doing this.

[gitchegumee]

Do NOT use steel wool unless you are 100% absolutely sure that it is stainless steel wool. Any carbon steel contact will rust the area of contamination. I suggest a new stainless wire wheel with tight knots and an angle grinder if there is some remaining discoloration. Don't use a stainless wire wheel that has been used on carbon steel.

[Moonlight]

Once the caustic has softened it, try the kitchen/restaurant supply stores for the largest hand-held scraper. It is my newest favorite for cleaning the kettle under even normal situations, eclipsing plastic paint scrapers.

[Todd Hicks]

Find the former brewer and stick his lazy butt in the kettle with your assortment of cleaning apparatus and chemicals. Keep locked in kettle until the kettle is perfectly clean and individual has learned the first lesson of brewing beer; cleaning and polishing kettles!

But seriously, even a good soak with hot PBW for several days will loosen up the baked on mess and allow most of it to be scraped off with a good SS scraper, restaurant scrubber, and good application of elbow grease. Afterwards, any mineral film deposits can be scrubbed away with a low-fuming foaming acid cleaner applied at high strength and a green scrubby pad. I use 5-Star StarSan or Ecolab Lime Away mixed with a little Quaternary Amonia (Quantum from 5-star) to give it some foamy surfacting properties. Keep rinsed off after cleaning a section to prevent any possible corrosion. Make sure to do an additional mild caustic CIP to get rid of the Quat and then repassivate the Stainless with a Nitric Acid wash.

If the kettle was that bad, I am sure the fermenters and bright tanks are equally soiled. If the beer stone or lime scale is really bad, I have used a strong dilution of Muriatic Acid and hot water about 1/2 gallon per bbl and run CIP for about 2 hours. Rinse with cold water, climb in with your foaming acid, green scrubby, SS restaurant scrub pad, SS scraper, and foaming acid cleaner and get to work. Remember, stone likes to build up on inside of pipes as well. That is going to take even more work to clean out. Get lots of brushes.

Good luck.

[Jephro]

Find the former brewer and stick his lazy butt in the kettle with your assortment of cleaning apparatus and chemicals. Keep locked in kettle until the kettle is perfectly clean and individual has learned the first lesson of brewing beer; cleaning and polishing kettles!

Right on man, bust him back down to a tank wipe!

[rafters_brewer]

Do NOT use steel wool unless you are 100% absolutely sure that it is stainless steel wool. Any carbon steel contact will rust the area of contamination.

Thanks for the info gitche - is that true even if you clean and passivate the kettle afterwards?

[gitchegumee]

Yes. Carbon steel will smear into the stainless substrate and cause it to rust. Passivation may eliminate some of the carbon, but depending on how much/how deep the contamination is, you'll certainly have rust in the future. Most stainless shops do not have any carbon steel in them. If a manufacturer does both stainless and carbon steel, they are almost always fabricated in separate shops. Of course there are stainless scrubbies for restaurant service that are in many breweries, but don't buy hardware-store steel wool! I would also advise against using any muriatic (=hydrochloric) acid for passivation. Chlorine at high temperatures will attack welds and high stress points in stainless. Use nitric acid CIP at 15% for 15 minutes at about 110 degrees F. Be sure to remove any brass parts, ventillate properly, wear protection, and AIR DRY the tank! Rinsing after the acid wash will not allow proper passivation. Cheers and good luck!

[Alex T]

Hi,

In one recent project we had a hot liquor tank full of build-up, rusty type deposits, etc. I got in a contractor with a high pressure blaster (wasn't an absolutley full-on one, just one that came mounted on the back of a small truck) - came up nice and shiny. That would be my ideal preference as (I don't think!) the high pressure water will affect the passive layer of the stainless, and you won't have any manual scrubbing. Then you might be able to just run a normal CIP and caustic brew to finish it off.......

For the CIP you may want to use chlorinated caustic as it is better for removing proteinaceous deposits. Then for good measure you could always give a quick circulation with nitric acid (to repassivate).

Alex

[Valleybrew]

The idea for a pressure washer is great, just wear safety glasses. That should peel off the nasty layer then I would follow with a heavy duty hot caustic soak then a nice acid soak when all organics are removed.
Steve

[gitchegumee]

Please see my update on passivation techniques here:

http://www.probrewer.com/vbulletin/s...2611#post72611