Sparge water treatment
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Nateo
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The only thing I add to my sparge water is enough acid to get the pH under 6. I'll add any other salts to the main mash or the kettle.
tgmartin000
Well-Known Member
Hmmm. That's not a bad idea. I usually just use all DI for sparging and hope my pH doesn't get too high.
Its not really pH that is the worry. Its alkalinity that needs our attention for sparging water. Alkalinity needs to be low for sparging use. If you're brewing with RO or distilled, then the alkalinity is low and no acidification is required. If the tap water has high alkalinity, then acidification is needed. There isnt a specific pH target for sparging water since the starting alkalinity of the tap water makes the difference in how low the pH has to be pushed to bring the alkalinity low enough. The pH target range is typically between 5.5 and 6. If the starting alkalinity is only moderately high, then a target of 6 may be appropriate. If the alkalinity is really high, then a target down in the 5.5 range might be needed.
The sparge water acidification calculator in Bru'n Water provides the tool for properly adjusting sparging water.
The sparge water acidification calculator in Bru'n Water provides the tool for properly adjusting sparging water.
I always point out that if you get sparge water pH to 6, no matter what the original alkalinity was, there is no way that the runoff will ever exceed 6.
Nateo
Well-Known Member
I'm not sure I understand what you're saying there. So let's say I have water that started with 500ppm CaCO3, that I acidified to a pH of 5.5, and RO water I acidified to a pH of 6. What you're saying is that the RO water will have a lower runoff pH than the first water?
Assuming the mash pH is lower than 5.5 to start about all you can say is that sparged with the high alkalinity water the runoff pH would never exceed 5.5 and sparged with the RO water it would never exceed 6. The high alkalinity water treated to pH 5.5 still has alkalinity of 85. The RO water would have alkalinity of about 1.5 or less. Where the pH actually goes will depend on the buffering capacity of the malt and the pH of the mash at the commencement of sparging.
In "Brewing Better Beer", Gordon Strong says (page 50): "Adding phosphoric acid is the easiest way to lower the pH of sparge water without adding undesirable flavors. Lactic acid is a distant second choice."
Nateo
Well-Known Member
Whatever acid you use will leave the "-ate" form of its ion. So phosphoric > phosphate, lactic > lactate, sulfuric > sulfate, etc. Malt has a bunch of phosphate already, so it won't impact the flavor much. Some people have a low threshold for lactate, although I don't. I've used lactic in the past without noticing any ill-effects, but I use phosphoric now because it's a lot cheaper.
Nateo
Well-Known Member
Under no circumstances should you use 5.2. Not in you mash, not in your sparge, not in your beer, period.
http://www.homebrewersassociation.org/forum/index.php?topic=1125.0
5.2 is a mixture of monobasic (mostly) and a bit of dibasic sodium phosphate. It forms a buffer, but not a good one, at pH close to 6 (I think I got 5.8 or so in DI water) but the buffering capacity is poor. So yes, the acidic phosphate salts will pull the pH down a bit but why not just use phosphoric acid and save yourself having to live with the sodium?
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