Negative Bicarbonate in Bru'n Water

Making a Steam Beer today and adding some lactic acid to get the PH to 5.3.  I see that with the acid addition my water with have a -19.2 bicarb.  What does that mean?

Dave

Just an educated guess but I think it means all your bicarbonate will be gone, fizzing all of it out as CO2, and then the negative value probably means that even if you added that much more bicarbonate in, it will still fizz out, whereas if you hit zero then there would be an even balance again.  Must be part of that balancing act known as “buffering”.

So what if any effect do you think that will have on the beer?

Lower pH, period.  If you wanted your mash pH to hit 5.3, and it does, then you have succeeded.  The only other concern is whether you’ve used too much acid and the pH is lower, maybe 5.0-5.1 or something.  If that’s the case, then obviously the beer might end up with an odd tartness.  All just educated extrapolations, I am not a water expert ala Palmer or Brungard (sp).

That’s what I thought.  I should be good to go!  Thanks.

Dave

Of course, there is no such thing as negative bicarbonate in chemistry.  But in Bru’n Water, its just an indicator of added acid in the water.

Since a positive bicarbonate concentration is neutralized by malt acids, a negative value just indicates that it is adding to the overall acidity of the mash. In the case of a low acidity mash grist (mostly base malt), there is a need for the mashing water to provide additional acidity (negative bicarbonate in the case of Bru’n Water’s convention) to reduce the mash pH to an acceptable level.  So in the case of that Steam Beer, the negative bicarbonate indicator is not a problem.

Enjoy!