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Old 01-13-2013, 04:09 PM   #11
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I've been wondering about people dropping their sparge pH this low and how it affected the final beer pH. I guess it doesn't hurt.
6.0 is not that low for sparging water, but it can be an acceptable target when the starting alkalinity of the sparging water source is low, ie: RO water.

If the starting alkalinity is much higher, then the ending pH target for the sparging water will need to be much lower. In some cases, a target of 5.3 might be needed to reduce the resulting alkalinity of the sparging water low enough. This is why Bru'n Water does not focus on a pH target for sparging water. It focuses on an alkalinity target and the user inputs the ending pH value needed to achieve that alkalinity.


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Old 01-13-2013, 08:49 PM   #12
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The attached graph makes it pretty simple to determine a reasonable target pH for sparge water. It shows the percentage of alkalinity that remains after treatment with acid to a a particlar pH. For example, if your water has alkalinity 100 and comes to you at pH 8 acidifying it to pH 6 with sulfuric or hydrochloric (CRS) or lactic acid will leave the alkalinity at about 32. OTOH if your water comes out of a well at pH 6.5 the post treatment alkalinity will be about 52. Note that Sierra Nevada treats all it's water to pH 5.5 with phosphoric acid (or so I'm told). For them the water, brew and sparge, will have alkalinity around 15% of the original pH given they are using phosphoric though it would be a little less (about 12%) if they used CRS all assuming they have source water with a pH 7 or greater.

Given that the guys at SN know a lot about this and that 15% of even 200 ppm as CaCO3 is only 0.6 mEq/L, that the boil will reduce pH and that the yeast don't have to take the beer lower than the pH at which alkalinity is typically determined (4.5 and that's the definition of alkalinity I used to develop the graph) it seems to me that going to pH 5.5 for sparge water seems the smart thing to do.





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Old 01-14-2013, 02:15 AM   #13
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I'll need to find some phosphoric acid then. I've been treating to around 6 because all I have currently is lactic acid and I don't like to add more than 3 ml to the 9 gallons of sparge water I'm usually treating because I feel like I can taste it if I add too much. Shooting for close to 6 has been working out so far as I haven't gotten over 6 with my final runnings and on my last beer (Dusseldorf Alt) I only hit 5.5 with the final runnings.

I think for lighter colored beers it may be a problem but I can always cut my water with RO if necessary for those.

Anyway, thanks for the responses guys, keeping my pH in check has substantially improved my beers and gotten rid of astringent and sharp flavors.

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Old 01-14-2013, 03:20 AM   #14
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it seems to me that going to pH 5.5 for sparge water seems the smart thing to do.
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Shooting for close to 6 has been working out so far as I haven't gotten over 6 with my final runnings and on my last beer (Dusseldorf Alt) I only hit 5.5 with the final runnings.
I've been chewing this one since I read it. If you are delivering 5.5 to the kettle then why go lower? I know people are wary of going over 6 which is the reason to lower the sparge temps to this. If you keep track of your sparge and you know it is adequately buffered by the mash should the sparge water still be lowered or is this just targeted at high alkalinity situations?
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Old 01-14-2013, 04:39 AM   #15
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There are really 2 things of concern here. First is keeping the runoff pH low enough that you don't get phenol extraction and second is being sure that the kettle pH doesn't get pulled too high by the alkalinity in the sparge water. I've never measured the buffering capacity of wort (I think Kai may have) but I'm thinking it's probably more than 10 mEq/L so that if the alkalinity of your water is 50 or less (1 mEq/L) you probably don't need to worry about acidifying it at all. If, OTOH, it's alkalinity is 200 then you do and getting that alkalinity under 50 (25%) is probably a reasonable goal. To do that for this particular example acid to pH 6 wouldn't be sufficient but acid to 5.5 would. It should be clear that sparge water acidified to pH 5.5 can never lead to runoff pH greater than 6 no matter what the extent of the dilution. However if mash pH is 5.4 and enough of this water is used in sparging the pH will rise to 5.5 if the sparge is continued long enough.

The proper thing to do, of course, is to check kettle pH both pre and post boil and make adjustments with acid directly in the kettle if necessary.

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Old 01-14-2013, 07:20 PM   #16
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I've been chewing this one since I read it. If you are delivering 5.5 to the kettle then why go lower? I know people are wary of going over 6 which is the reason to lower the sparge temps to this. If you keep track of your sparge and you know it is adequately buffered by the mash should the sparge water still be lowered or is this just targeted at high alkalinity situations?
This last batch came out with final runnings at 5.5 because the mash contained some darker grains. I have made beers without acidifying the 100 ppm alkalinity sparge water and have come dangerously close to 6 pH. I have made plenty of beers in the past with astringency and even low levels of it really bother me, so now that I know all that it takes to avoid it is keeping the water temp under 170 and the sparge pH around 6 or lower I will always do both from now on. Measuring and acidifying sparge water is easy and cheap and unless you go crazy with the acid I don't think there's any down side.
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Old 01-15-2013, 01:05 AM   #17
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OK you lost me here.

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To do that for this particular example acid to pH 5 wouldn't be sufficient but acid to 5.5 would.
Seems to me, sparge at pH 5 is probably too much acid, pH 5.5 will work for sure, and pH 6 is marginal, depending on alkalinity and grain bill.

Am I missing something?
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Old 01-15-2013, 01:34 AM   #18
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This threw me too. I think he meant to say acid to pH 6 wouldn't be sufficient but acid to 5.5 pH would. That's the way I'm reading it anyway, or I am going to be really confused.

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Old 01-15-2013, 11:27 PM   #19
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Yes, I did. Sorry about that. I went back and fixed it.



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