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Final Beer pH -- Phosphoric Acid Off-flavor

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  • #16
    Not speaking of alpha acid isomerization, though that is effected by pH. The pH of the finished beer going up when a dry hop is used means that there is a process that is either changing the buffer ratio of the system, or it is neutralizing it. Either way, if you add acid to it, you can push the products back into another form which will either make them unavailable, or even taste differently. In chemistry, the reaction does not always proceed forwards, it moves back and forth between reactants and the products, changes in the environment can also drive this reaction forwards or backwards in favor of the products or reactants. So, by changing the pH after the dry hop, you will be altering the chemistry that is going to affect flavor in the final product. You ought to look at reducing your pH earlier in the process, with mash adjustments or sparge water adjustments. Then leave the final product alone, you don't know what the effects(and they haven't been studied) of post fermentation and dry hop pH adjustments.

    Originally posted by Viridian View Post
    Hop utilization being alpha acid isomerization that you're referring to -- right? That's entirely different when compared to extraction of aroma oils from the hop charge.

    There are countless white papers around the internet (wiley library is a good start) that reference common pH ranges of certain beer styles, and their benefits. Aside from helping with colloidal stability and microbial mitigation, the pH affects the flavor perception of the beer.

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    • #17
      Originally posted by jebzter View Post
      Not speaking of alpha acid isomerization, though that is effected by pH. The pH of the finished beer going up when a dry hop is used means that there is a process that is either changing the buffer ratio of the system, or it is neutralizing it. Either way, if you add acid to it, you can push the products back into another form which will either make them unavailable, or even taste differently. In chemistry, the reaction does not always proceed forwards, it moves back and forth between reactants and the products, changes in the environment can also drive this reaction forwards or backwards in favor of the products or reactants. So, by changing the pH after the dry hop, you will be altering the chemistry that is going to affect flavor in the final product. You ought to look at reducing your pH earlier in the process, with mash adjustments or sparge water adjustments. Then leave the final product alone, you don't know what the effects(and they haven't been studied) of post fermentation and dry hop pH adjustments.
      I appreciate that insight. It is certainly possible that the off-flavors I am experiencing is due to the acid and pH adjustment being made after the volatile aroma oils are introduced. I also agree that I've had a troublesome time finding research papers or solid technical highlights of how to adjust final beer pH. I am good with moving forward on my next batch (this friday) by aiming for a casting wort of pH=4.5 or so, to hopefully mitigate the need from final beer pH adjustment entirely. The only concern I now have is - should I balance between using phosphoric and lactic acid to accomplish this, in order to ensure I don't approach/exceed the flavor threshold for either one? Perhaps introduce even a third acid if necessary.

      Thanks for the feedback, I hadn't thought of the chemical process implications of changing the buffer contents of the solution (hop oils / materials) by acidifying. Nice catch.
      Ryan
      Viridian Brewing Company
      [Brewery-In-Planning]

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      • #18
        Originally posted by jebzter View Post
        Not speaking of alpha acid isomerization, though that is effected by pH. The pH of the finished beer going up when a dry hop is used means that there is a process that is either changing the buffer ratio of the system, or it is neutralizing it. Either way, if you add acid to it, you can push the products back into another form which will either make them unavailable, or even taste differently. In chemistry, the reaction does not always proceed forwards, it moves back and forth between reactants and the products, changes in the environment can also drive this reaction forwards or backwards in favor of the products or reactants. So, by changing the pH after the dry hop, you will be altering the chemistry that is going to affect flavor in the final product. You ought to look at reducing your pH earlier in the process, with mash adjustments or sparge water adjustments. Then leave the final product alone, you don't know what the effects(and they haven't been studied) of post fermentation and dry hop pH adjustments.
        I personally favor Acidulated malt for these reasons. Lowering initial pH.

        I too prefer the "clean" taste of lactic acid to phos, but also prefer to make the beer as traditional as possible, whenever I can.

        Phosphoric costs a lot more, and in locations where people care (hippy cities) phos is much worse for the environment.

        Again, personally, I am willing to do whatever I think makes a better end product overall. Almost every brewery I have visited does something slightly different. Just my $0.02

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