Bicarbonate in water

Physics, chemistry and biology of brewing. The causes and the effects.

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Joined: Sat Nov 18, 2000 6:35 am

Bicarbonate in water

Post by Dane » Mon Mar 26, 2001 10:26 am

I recently got hold of an analysis of my tap water,
as I wanted to brew a pilsner and have read that
this can be important. It looked OK:
Ca:115 Mg:22 Na:51 Cl:80 SO4:82 and then the killer
HCO3: 348! Everything I have read says this is
BAD - and then gives some imprecise advice like
"boil it" or "add acid".
Anyone do this to their pilsner water? I could also
dilute it with rainwater which should be totally
soft, to get it even lower.

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caution against rain water

Post by bredmakr » Tue Mar 27, 2001 5:29 am

First, having a high bicarbonate means that the water is very hard. Boiling it will reduce the bicarbonate/hardness and lower the pH. You know its working when you see the Ca-MgCO3 precipitating on the side of the kettle. This in turn frees hydrogen ions and reduces the pH which is the main problem. What was the pH of the water sample? You could also add phosphatic acid to lower the pH, but be careful. As for rain water I would highly recommend avoiding it. You might be surprised by what is in rain water. I would recommend using bottled drinking water, distilled water, or some other source that filters the water with a reverse osmosis process. Another way to reduce it is to add some salts to the water. You'll have to check around for the right amount. There is a good article in the latest Brew Your Own about treating hard water for brewing with salts. Good luck!

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Post by Dane » Tue Mar 27, 2001 8:04 am

The pH is (apparently, its the water company's
analysis) 7.64 normally. Question is, if I boil,
how will I know how much Ca/Mg I have lost?
Whats the chemistry of the phosphatic (phosphoric)
acid reaction? That would seem to be more
predictable, as long as the by products aren't
problematic in themselves.

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