Rain water question 2
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simple one
- CBA Prizewinner 2010
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Rain water question 2
Am I right to think that if my alkalinity drops by the rain by say, 10%. The other minerals all drop by the same percentage?
-
simple one
- CBA Prizewinner 2010
- Posts: 1944
- Joined: Tue Oct 28, 2008 11:35 am
- Location: All over the place
Re: Rain water question 2
Bumpy bump. Any ideas?
Re: Rain water question 2
Hi Simple one,
I can't give you a definitive answer but I'll have a go at an answer anyway. I would say it depends on your water.... Rainwater is usually acidic and can vary from pH 2 ! (acid rain) to the more usual (still acid) value of around 5.5 - 5.7. The acidity is caused by dissolution of atmospheric gases which further react to give acids. As I understand it, normal rainwater can contain around 20 microMolar sulfate (SO3 - about 2 ppm), and smaller varying concentrations of nitrate (NO2) and bicarbonate (HCO3). It can also contain trace amounts of calcium. While these values are small they can have an influence if you have very soft water.
Because the rainwater is acidic it could affect the alkalinity - so your decrease by 10% may not be a dilution factor decrease but also due to some alkalinity removing acidity from the rain....
That being said - if you already have hard/ mineral water and live in an unpolluted area I expect these effects will be small (a couple of percent maximum) and the concentration of ions in the rainwater negligible for brewing purposes, if you already have very soft water that might not be the case. Martin Brungard might be better able to answer this than me.
I can't give you a definitive answer but I'll have a go at an answer anyway. I would say it depends on your water.... Rainwater is usually acidic and can vary from pH 2 ! (acid rain) to the more usual (still acid) value of around 5.5 - 5.7. The acidity is caused by dissolution of atmospheric gases which further react to give acids. As I understand it, normal rainwater can contain around 20 microMolar sulfate (SO3 - about 2 ppm), and smaller varying concentrations of nitrate (NO2) and bicarbonate (HCO3). It can also contain trace amounts of calcium. While these values are small they can have an influence if you have very soft water.
Because the rainwater is acidic it could affect the alkalinity - so your decrease by 10% may not be a dilution factor decrease but also due to some alkalinity removing acidity from the rain....
That being said - if you already have hard/ mineral water and live in an unpolluted area I expect these effects will be small (a couple of percent maximum) and the concentration of ions in the rainwater negligible for brewing purposes, if you already have very soft water that might not be the case. Martin Brungard might be better able to answer this than me.