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Thread: Keg Washing with Lye

  1. #1
    Join Date
    May 2015
    Location
    Hammelburg, Germany
    Posts
    12

    Keg Washing with Lye

    Hi all,

    A distiller friend of mine here in Germany gave me some lye to clean my kegs with and it worked great. It cleaned much better than my previous routine, which is telling since I used quite a diluted solution, 50 grams for 20L, recommended is 350 grams for 20L. For each keg, I pumped the lye solution through at 80C, emptied, then pumped 95C water through for one minute as a rinse.

    Is my rinse long enough?

    Is it necessary to passivate the kegs after this? (I also read up on the possibility of corrosion, but from what I have gathered that can really only occur at concentrations higher than what I am using.)

    Thanks for the help!

    Prost,
    Dave

  2. #2
    Join Date
    Oct 2002
    Location
    Chesterfield, UK
    Posts
    1,577
    Without having a better knowledge of what your "lye" contains in chemicals, and without perhaps knowing what you were using before, a definitive answer is not possible. However, assuming it is sodium hydroxide, or less likely, potassium hydroxide, plus various additives to help the hydroxide to work more effectively and prevent scale build up, then no, you don't need to passivate.

    If you are using potassium hydroxide based material, then my understanding is that this is far more expensive than sodium hydroxide based material, and you are highly likely to be wasting money and should switch to a sodium hydroxide based equivalent. I have only ever used KOH for degreasing new equipment, but now simply use stronger NaOH at higher concentrations and higher temperature than for normal CIP - and it seems to work well.

    You should never need to passivate, apart possibly when you first get new equipment. Degrease, give a normal clean, passivate then give a normal clean before use for brewing. Kegs, with the exception of some Chinese kegs I have seen don't normally need passivation as the steel quality is good, and, if from US or European suppliers, will probably have been degreased then passivated by the manufacturer.

    NaOH does not strip the protective layer of chromium dioxide from the stainless (which is what makes it stainless).
    dick

  3. #3
    Join Date
    Nov 2016
    Location
    United Kingdom
    Posts
    53
    Again hard to say without a more thorough description of lye.

    From my limited understanding lye means caustic, that is sodium hydroxide (NaOH) with additives. This is occasionally used a water hardener. If you are worried about the effectiveness of your rinses then measure the pH of the rinse water coming out of the kegs and compare it to the pH of the rinse water going out. If Health and Safety is not a concern (and it should be!) you can always check if the rinse water feels soapy from residual lye.

    Also, and forgive me if I am stating the obvious, but make sure you thoroughly rinse out the CO2 from the kegs as this will seriously degrade the cleaning power of caustic.

  4. #4
    Join Date
    May 2015
    Location
    Hammelburg, Germany
    Posts
    12
    Sorry that this response is so late, but we have been expanding our space here and that has pretty much taken up most of my time since I am doing a lot of the work myself.

    I received more information from my distiller friend about the lye. It is sodium hydroxide (here in Germany they call everything "lauge" which means caustic although they mean sodium hydroxide. I guess it is kind of implied?).

    My cleaning regime has been the same since changing to the sodium hydroxide-based solution, except that I lowered the temp to around 70C for caustic cleaning. Rinsing still remains the same.

    Everything is going well, so thanks for the info!

    Prost!
    Dave

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