Author Topic: Mash pH and water chemistry  (Read 7210 times)

GottBeer

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Mash pH and water chemistry
« on: June 11, 2009, 09:05:04 PM »
I'm fairly new to all grain brewing and lately I've been paying more attention to my mash pH and water chemistry.  Typically all the grains are mashed together and with my water supply I usually add a bit of baking soda to my mash water to raise the alkalinity when brewing dark beers.  But now I'm thinking of tackling "The Other Michael Jackson (Black Witbier)" in the current issue of Brew Your Own, and this recipe calls for mashing just the pils malt, wheat (flaked), and oats (flaked) and not adding the dark specialty grains until recirculation and sparge (in a sense it seems like the dark grains are being steeped in the lauter tun).  So my question is, should I be adjusting my brewing water to target just the light grains in the mash and essentially ignore the late addition of the dark grains (at least in terms of pH)?  And any reason to mess with the sparge water (e.g., for tannin extraction)?  I appreciate any feedback.

Offline MaltLicker

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Re: Mash pH and water chemistry
« Reply #1 on: June 12, 2009, 05:37:08 AM »
I'm no expert, but I think the general idea is to adjust the minerals/pH of the mash, given the water profile and grains therein.  So if the SRM of the mashed grains is only 7, then use mineral adjustments for that.  Part of the reason for minerals is to compensate for the dark grains' acidity, depending on your native water.  (Dublin water naturally had those minerals to buffer large amounts of dark grain; Plzen did not.)

On sparge water, the conventional wisdom is to keep the pH of sparge water under 6.0 b/c alkaline water could strip tannins from the grains more easily than slightly acidic water.  A tiny amount of phosphoric acid will do it, as in one drop for some people.  In my stove-top method, I would put one spatula of the mashed grains into the four gallons of sparge water, and that was enough to drop the pH below 6.0.  My native water has pH of 8.7.  I just bought some phosphoric acid and will try that next week. 

GottBeer

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Re: Mash pH and water chemistry
« Reply #2 on: June 12, 2009, 09:44:40 PM »
Thanks for the input.  I was talking to some people today and the consensus was to match the pH to just the grains being mashed and, in this case, to ignore the dark grains (since they are being added after the mash).  So I'm going to go with that and see what happens.  My native water is about pH 7.4, so I may just leave it alone for sparging (still thinking about it).

I've read that phosphoric acid will reduce the calcium in the water so you may want to watch that (not sure if it matters as much for the sparge).  In any case, good luck with the next batch.  It'd be interesting to hear how it goes.

Offline BeerSmith

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Re: Mash pH and water chemistry
« Reply #3 on: June 12, 2009, 10:19:28 PM »
Hi,
  This article I put together last year covers this topic pretty well:
    http://www.beersmith.com/blog/2008/10/05/beer-ph-hard-water-treatment-for-brewing/

Cheers,
Brad
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