In a recent post, Martin said pertaining to 88% lactic acid—-“1ml per gallon 88% lactic is no problem at all. Its around 1.5 ml/gal that the 88% lactic will definitely have flavor impacts.”
Are there similar parameters to using 85% phosphoric acid? And if so what are they? And above what level is there a taste impact? And what is the taste?
Thanks!
Phosphate compounds are relatively “flavor neutral” while lactate compounds have a more noticeable flavor impact. It is for this reason that phosphoric acid is generally regarded by many as the “best” acid to use in brewing.
And following is a somewhat different but perhaps even more valid argument based on the amount of phosphates already present in malt:
Regards,
David M. Taylor
B.S. Chemical Engineering
I prefer lactic for two reasons, apart from taste:
Lactic acid is the only acid that will occur naturally in traditional brewhouse processes (you simply can’t avoid its presence in beer, and its production is the mechanism of biological acidification in Continental practice) and
Phosphoric acid precipitates calcium through apatite reaction, throwing off the balance of your RA and mineral calculations and bringing you back to the beginning, possibly repeatedly.
Both of these points can be overstated, I acknowledge.
Phosphoric acid is used in soft drinks, the pH of Coke is ~2.5. It keeps those from being flabby/syrupy. Not much taste, is there?
Yup, there’s not an unpleasant degree of acid character in Coke (or other cola), at least not to most people I know.
Then for contrast, try slamming a well aged kombucha with a pH of 2.5, which is basically a combo of lactic acid and acetic acid (vinegar), or maybe a mixed “shrub” (vinegar drink – look it up) – some people might be able to “enjoy” these beverages, but most will complain of the burning acid sensation. Not as pleasant to the masses as cola.
Rob, the calcium phosphate precipitation reaction requires sufficient calcium content in the water in order for that reaction to proceed. If your calcium is high enough to induce the reaction, you probably don’t need to worry about your wort being short of calcium.
Martin, that’s what I meant by “this can be (usually is?) overstated.” But it is a potential complication I think anybody using phosphoric should be aware of, even if it isn’t a practical problem for them. It can affect RA, if you are calculating this yourself. Can I assume that Bru’n Water works this out for us if we select phosphoric as our acid?
Oh, I sure don’t need to add more complication to that program. Bru’n Water doesn’t consider that phosphate precipitation reaction.
Brewers that are interested in exploring if their water and its calcium content are at risk when using phosphoric acid should review the charts that AJ Delange incorporated into the Water book. They’re reasonably easy to use.
Thanks. That book is where I became aware of this. I won’t ever worry about it myself anyway, as I like lactic as a “shortcut” mimicking biological acidification, but it’s an interesting illustration of how everything we do affects other things in ways we might not have considered.