Exactly How Caustic is 85% Phosphoric Acid?

Discussion in 'General Brewing Discussions' started by gsteiner, Dec 9, 2014.

  1. gsteiner

    gsteiner New Member

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    Hello everyone,

    The subject pretty much says it all... I really haven't been able to find any meaningful data online, just the standard acid precautionary warnings. Just looking for perspective from anyone who's worked with it\ before.

    Just for background... I have worked with strong concentrations of HCL and Sulfuric acid in the lab before (it's been a few years) so I have respect for corrosive chemicals and know how to safely handle them.

    What I really want to know is: how corrosive is 85% Phosphoric Acid? Is this stuff as nasty as 85% Sulfuric, where a drop will burn a hole through your flesh or is it just going to leave a red spot the equivalent of a sunburn if it sits there for 30 seconds?

    Don't want to go overkill and don a Class B Hazmat suit just to adjust my brew water pH if it's not absolutely necessary (j/k).... :)
     
  2. Nosybear

    Nosybear Well-Known Member

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    Nowhere nearly as caustic as sulfuric acid. I wouldn't want to handle it without gloves but I wouldn't worry about it burning holes in stuff.
     
  3. gsteiner

    gsteiner New Member

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    Ok. good to know. I suspected as much, but wanted to get some perspective from others who have worked with it before.

    I've worked with Sodium Hydroxide (lye) quite a bit and have found that, for me at least, short term skin exposure during handling (aka a careless friend spills some on you) had pretty much zero affect despite all of the highly caustic warnings associated with it. And that's at 100% concentration.

    Was wondering if despite it's 85% concentration rating, the phosphoric acid was similar... but of course I have no plans to dip my finger in it to find out :mrgreen:
     
  4. Brewer #21703

    Brewer #21703 New Member

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    Technically not caustic, but an extremely strong acid and corrosive. The term caustic typically associated with strong bases such as sodium hydroxide (used in drain cleaners) which can also be corrosive.
     

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