Cleaning Plate Chiller with Lye

Quick note to record my experience.

I mixed about 3 tsbp dry lye into a quart of water. Funneled into plate chiller till it ran out the back. I had some tubing connected to the backside in a way to capture the lye solution and not allow it to run off.

After about 2 hours, I hosed out all sorts of nasty grime. Worked great.

The manual for the Therminator (the chiller I have) said to NOT use caustic, such as lye, to clean due to the copper in the chiller. So, I do not recommend this method of cleaning, and I will not be doing it again. However, it did work great once I guess I'll go back to my oxyclean rinse.

Have you ever tried citric acid? I work HVAC and have used a mild solution of citric acid to clean coils on jobs that restrict the use of chemicals. Works nearly as well as my heavy duty chemicals, and is totally non toxic. I've used it on my immersion chiller with excellent results as well!

No I haven't. Is this something you buy, or make? I'd guess it works similarly to the acids I normally use, like starsan and vinegar.

Lye is a base and apparently reacts with copper.

It typically comes in a powder (looks a lot like dextrose). I got my last batch from a whole foods place near where I was working, but you can also get it online.
Both acidic and alkaline solution do react with copper. You're more or less "etching" the surface to clean away oxidation. This allows for optimal thermal transfer which is what your going for. I'm sure if you did a side by side comparison, the "non cleaned" coil would last a little longer, but the properly cleaned coil is going to do it's job better every time. Keep in mind I work on some AC units that have been cleaned with much stronger chemicals 2-3 times per year for over 20 years and still going..........

501irishred said:

It typically comes in a powder (looks a lot like dextrose). I got my last batch from a whole foods place near where I was working, but you can also get it online.
Both acidic and alkaline solution do react with copper. You're more or less "etching" the surface to clean away oxidation. This allows for optimal thermal transfer which is what your going for. I'm sure if you did a side by side comparison, the "non cleaned" coil would last a little longer, but the properly cleaned coil is going to do it's job better every time. Keep in mind I work on some AC units that have been cleaned with much stronger chemicals 2-3 times per year for over 20 years and still going..........

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Hmm. I wonder why the strong warning not to use caustic. Maybe it etches faster? The manual does allow the use of starsan, but not for extended periods.

Everything in moderation I'd say. The key to only use as much as you need, and leave in contact only as long as needed to clean properly. Any more is doing more harm than good. I talked about those old, properly maintained units? I replaced the coils on several similar units (but much newer) last year that were destroyed because the business owner sprayed the coils with cleaner but did not rinse them. The copper was thin in places, but the aluminum was almost gone....... Properly mixed starsan for 5min, ok, straight starsan for 12hr, not ok.......
I may have to do an experiment using the citric acid solution and see what it would take to be detrimental. From what I've seen of it so far, I have a feeling you would have to get a little silly with it to do any harm.

The problem, as I understand it, is that citric acid will clean/remove the gunk, but will not liquefy the gunk into a liquid. Lye will liquefy the organic matter into a sludge and allow removal more easily. Think of it as melting fat in a hot pan.

MC

I've used citric acid to clean my plate chiller and it worked great! It also worked very well for removing beerstone from my boil kettle. The water coming out of the chiller was slightly green. Not sure if that's bad or not.

Someone tell me if it's not a good idea. I got the citric acid powder for a barrel project, saw it laying in a bag and said "wonder how this will work to get the junk off my kettle."

Misplaced_Canuck said:

The problem, as I understand it, is that citric acid will clean/remove the gunk, but will not liquefy the gunk into a liquid. Lye will liquefy the organic matter into a sludge and allow removal more easily. Think of it as melting fat in a hot pan.

Can neither confirm nor deny. Different types of gunk react better to some cleaners better than others. I know it works well on grease, and basic dirt build up, just not sure about dried wort and and hop debris.

MC

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cadillacandy said:

I've used citric acid to clean my plate chiller and it worked great! It also worked very well for removing beerstone from my boil kettle. The water coming out of the chiller was slightly green. Not sure if that's bad or not.

Someone tell me if it's not a good idea. I got the citric acid powder for a barrel project, saw it laying in a bag and said "wonder how this will work to get the junk off my kettle."

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The green is most probably oxidation that has been removed (can be green, white or black), which is a good thing. Oxidation build up on copper acts as an insulator and reduces the thermal transfer efficiency. Guess it could also be hop debris. Either one would be a plus.

Never thought about using citric acid for the plate chiller. I use it for cleaning the hard water deposits in the boilers of my espresso machine.

Hmmm... I've regularly dipped my immersion chiller in PBW - does a great job of cleaning wort off, and leaves it a bright copper color. Says its safe for soft metals...