Ask The Brewmasters

  • 1.  Corrosion to inside of can for low pH RTDs

    Posted 04-13-2023 20:20

    Hello, I was wondering if anyone had experience with low pH RTDs corroding away at the inside of the can. Our cans have the usual protective coating, but we are looking to make a new RTD that has a pH lower than any of our other beverages. The pH could be as low at 2.6, which I believe is comparable to some soft drinks. I am wondering if we need to be concerned about corrosion at this pH? Thank you!



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    Rachael Bepple
    Pacific Western Brewing Co
    Prince George BC
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  • 2.  RE: Corrosion to inside of can for low pH RTDs

    Posted 04-14-2023 12:40

    Rachael:

    You should definitely talk through this with your can supplier to make sure that the coating they are using has been tested at the pH level and with the acids that will be present in the liquid.

    It can get confusing when talkling through coating options, but basically there are two different chemistires that can be used.    Epoxy or Urethane.    As a general rule, epoxy coatings will be more brittle and have more chemical resistance.   The urethane coatings have less chemical resistance, but are more flexible.    Both have upsides and downsides and you will have to evaluate what works best for your products and processes with your supplier.....I would be looking at what epoxy coatings your vendor offers for the pH range you have listed.



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    Chris Mehr
    Director of Quality
    Revolution Brewing
    Chicago, IL
    cmehr@revbrew.com
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  • 3.  RE: Corrosion to inside of can for low pH RTDs

    Posted 04-14-2023 12:40
    We didn't have corrosion but did have a lot of problems with the BPANI can liners when they first came out with our low-pH sour beers. It was actually dissolving the can liner. I would definitely test some of your cans with that product in it for a couple of weeks at room temp or higher. Then tear the can open and see if you can scratch the liner with your fingernail. If it feels soft, even a little bit, don't use those cans. The Epoxy can liners that were used before California banned BPAs were much more robust. You should probably make it a habit to ask what liner formulation is used in the cans you get and keep a test log. The liners aren't always the same among manufacturers and also vary depending on where they are being sold.


    Tom Handy
    Owner
    Paradise Creek Brewery

    Downtown Restaurant
    245 SE Paradise 
    Pullman, WA 99163
    509-338-9463

    Production Facility
    Trailside Taproom
    505 SE Riverview St.
    Pullman, WA 99163
    509-339-6894





  • 4.  RE: Corrosion to inside of can for low pH RTDs

    Posted 04-17-2023 14:11

    Rachel,

     

    Good advice from others to check with your supplier. If you want to learn more about the variety of material used in can liners, check out these resources:

    https://www.brewersassociation.org/collab-hour/introduction-to-beverage-can-and-end-coatings/

    https://www.brewersassociation.org/brewing-industry-updates/know-before-you-buy-beer-can-specifications/

     

    And if you are attending the Craft Brewers Conference in May, check out this presentation:

    https://www.craftbrewersconference.com/seminars/session#60?session-title=aluminum-beverage-can-corrosion-in-sour-beers-and-other-

     

    Chuck Skypeck

    Technical Brewing Projects Director

    Brewers Association




    Original Message


  • 5.  RE: Corrosion to inside of can for low pH RTDs

    Posted 04-14-2023 18:57

    Hello Rachel - 

    Please contact me directly - tammy.duhaime@americancanning.com - American Canning has just begun manufacturing aTULC cans here in Austin, TX where we are headquartered. This can has a unique PET liner on both the inside and outside and is designed for hard to hold beverages with low PH, high acidity, salts, sulfites etc. Most beverage with just one of the above ingredient are failing in traditional cans OR have a very short shelf life. Please note this can can be used in California and is 100% recyclable. 
    Since the liner is applied directly to the aluminum coils prior to manufacturing and not sprayed on it is next level when it comes to a premium liner. It is also why we are a waterless can plant, we manufacture using a dry process and the greenest can plant on the planet. This method has been used in Japan for over 40 years. I would LOVE to send you samples for your own in house testing and can also share more data and the how's and why this can is a game changer in the beverage industry. 
    Please follow this link to read more. 
    https://www.ecosystem.americancanning.com/company-news/atulc-manufacturing-process

    Thank you 

    Tammy



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    Tammy Duhaime
    Supply Sales Manager
    American Canning
    Austin TX
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  • 6.  RE: Corrosion to inside of can for low pH RTDs

    Posted 04-15-2023 09:47

    Rachel,

    This is a great question to post here. Having familiarity in this subject you definitely need to be concerned.  I would suggest you work with your can supplier to determine its corrosivity and potential risks.  Also, it is imperative to control total package oxygen levels as well.  At these low pH levels, TPO control is paramount.  Your can supplier will be able to provide guidelines. 

     

    Also, if you have any chlorides or citrus based flavors in your RTDs this will only compound your risks associated with primary corrosion. 

     

    Best of luck!

     

    Sent from Mail for Windows

     






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