Plate chiller baking for maintenance reasons

[Homer]

Been searching around and seems like a lot of people bake their chillers, but some people are saying that this could possibly bake on some crap and render the thing useless (for sanitary reasons). I have a few years worth of brewing through my Duda diesel and wonder if I should actually give this a shot. I typically back flush with hot pbw after brewing. Also, will baking destroy the big label affixed to the top of the chiller?

Thanks

 

[thekraken]

I have no experience baking chillers but from my little cast iron refinishing experience I can assume any residual sugars not flushed out would get baked on much like seasoning on a skillet (polymerization??). That said, an easy peasy way to remove decades (or more) of baked on seasoning from a skillet is a good soak in a lye bath... but I have no idea what kind of reaction lye will have with copper/copper brazing.

(edit)
Holy **** that reminds me I have a skillet sitting in a lye bath in the back of the shed now. It has to have been sitting in the bath for 3 years now!! I'll have to check it after work... sorry for the derailment.

 

[passedpawn]

John Blichmann says don't do it. Don't use lye either. Hot water and PBW was his instructions to me for cleaning when I brought it up. I did bake mine once, no ill effect, but I did end up having to flush out a bunch of black flakes and stuff.

 

[thekraken]

John Blichmann says don't do it. Don't use lye either. Hot water and PBW was his instructions to me for cleaning when I brought it up. I did bake mine once, no ill effect, but I did end up having to flush out a bunch of black flakes and stuff.

He would be the man to ask. Did he elaborate to what was wrong with using lye?

 

[passedpawn]

He would be the man to ask. Did he elaborate to what was wrong with using lye?

I interviewed him for 2 hours and never had the energy to transcribe the recording to text, so I don't have easy random access to the interview. But I think he mentioned affecting the copper brazes in the Therminator. Of course, I assume the Duda chillers are identical construction.

 

[beermanpete]

A brief internet search indicates copper does not react with lye but copper sulfates and other copper compounds will. The sulfates will create a blue color that should be visible in the water used to flush the parts. I have noticed this same blue color when using PBW to clean my heat exchanger so it also seems to break down the sulfates. All things considered why bother with an aggressive and dangerous cleaning solution (lye) when a safer option (PBW) is available?

 

[thekraken]

Well, per passedpawn's conversation with Palmer I'd say don't use lye. I was speaking in regard to baked on polymerized residue per baking for maintenance, not just sticky residual sugars. But since you asked, in general when working with lye put on some ppe, use a little common sense and you'll be fine. You just need to respect it, no need to fear it. I suspect as far as pure cleaning power that PBW wouldn't be in the same league as lye. I wonder if PBW could remove seasoning off a skillet?

But again, it's moot. Palmer's the man.

 

[passedpawn]

Well, per passedpawn's conversation with Palmer I'd say don't use lye. I was speaking in regard to baked on polymerized residue per baking for maintenance, not just sticky residual sugars. But since you asked, in general when working with lye put on some ppe, use a little common sense and you'll be fine. You just need to respect it, no need to fear it. I suspect as far as pure cleaning power that PBW wouldn't be in the same league as lye. I wonder if PBW could remove seasoning off a skillet?

But again, it's moot. Palmer's the man.

*Blich, not Palmer. Also, I have cleaned mine with lye. Did an hour soak in a very strong solution. Really cleaned it out! But I never did it again after that once.

 

[Duda_Energy]

The problem with lye is it removes the top coating of chromium oxide from the stainless plates, which is one of the major factors in making stainless stainless.

As long as it doesn't remove much, and is then let sit and exposed to air for a day or so, the oxide layer reforms and you're fine. Think about stainless steel grills used in restaurants - lye water is the correct way to clean them...but that metal slowly gets thinner and thinner over the years. The plates in the heat exchanger are already thin by design for maximum heat transfer.

Add to that some brewers who clean with lye don't realize the importance of letting the stainless interact with oxygen for a while after the cleaning. Never really an issue on a grill in the restaurant, those are always exposed to air. But I've seen brewers immediately run a batch after cleaning (treating the lye as the sanitizer) or capping off the ports, or worst of all, leaving a cleaning solution in the unit to soak for days. Without the oxide layer, rust happens.


All that said, flushing the unit with lye water is my top recommended method for an extreme clean of our heat exchangers when nothing else works. But it does do damage to it. I wouldn't do it more than once a year.
Best thing you can do is make sure you have a good hops spider and don't let the trub into the unit in the first place.