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Brews & Views Bulletin Board Service * Brews and Views Archive 2006 * Archive through December 23, 2006 * PH of Sparge water... How much Phosphoric to use? < Previous Next >

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Chad D.
Intermediate Member
Username: Icehouse

Post Number: 460
Registered: 02-2003
Posted From: 63.224.186.98
Posted on Tuesday, December 12, 2006 - 04:50 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I am going to start tweaking my sparge water. I've never done it before.

My PH runs between 9 and 10.

I have a 10% solution of Phosphoric Acid from Northern Brewer. How much should I use?

Any ratios of this solution would be greatly appreciated.

Thanks!
Chad
 

Rob Beck
Intermediate Member
Username: Robbeck

Post Number: 301
Registered: 03-2003
Posted From: 65.64.102.30
Posted on Tuesday, December 12, 2006 - 05:06 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

You really need to have a pH meter or pH test strips if you're going to start adding acid. The composition of your water is undoubtedly different from water in other locations. I treat my sparge water and the number of drops of acid from an eyedropper will vary,depending on the time of year and on the amount of rainfall, in order to get to the same final pH of the water.
I have found that once you get to that delicate balancing point between the carbonates/bicarbonates and the acid that the pH will drop dramatically with the addition of one more drop of acid.
 

Bill Pierce
Moderator
Username: Billpierce

Post Number: 6040
Registered: 01-2002
Posted From: 24.57.224.220
Posted on Tuesday, December 12, 2006 - 05:10 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

It's all but impossible to accurately predict the amount of acid to add. You need a reliable means (a meter or high quality pH strips) of measuring pH. I would add phosphoric acid 1/2 tsp. at a time (1 tsp. if you brew 10 gallon batches), take a reading and add more if necessary.

It's less important if you batch sparge, but the ideal range for the sparge water pH is supposed to be 5.7 - 5.8. My own considered opinion is that anywhere between 5.0 and 6.0 is close enough.

Again, I think it's better to do nothing if you don't have a way of accurately measuring pH. Buy or borrow some high quality strips (I favor the plastic coated ColorpHast strips from Merck) or a meter.
 

Chad D.
Intermediate Member
Username: Icehouse

Post Number: 461
Registered: 02-2003
Posted From: 63.224.186.98
Posted on Tuesday, December 12, 2006 - 08:52 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

As always...

Thanks guys. I just decided to add a half dose of 5.2 into my sparge water today. I got pretty good efficiency.... but I have noticed a much lower efficiency ever since I switched to a Bazooka Screen. I batch sparge, and used to get 80% plus with a stainless dishwasher supply braid.

Also, it takes me about 6 gallons of recirculating before my runnings are clear enough to go to the boil kettle. Anyone else have this problem with the bazooka?
 

Bill Pierce
Moderator
Username: Billpierce

Post Number: 6042
Registered: 01-2002
Posted From: 24.57.224.220
Posted on Tuesday, December 12, 2006 - 09:29 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I'm not sure the Five Star 5.2 pH buffer would be effective in adjusting the sparge water pH. It's intended to be used in the environment of the mash with its malt phosphates, which as I see it is rather different from the bicarbonate/carbonate regime of tap water by itself. However, I'd welcome some input from a real chemist (I miss Adam W at times like this).
 

Tim Wi
Advanced Member
Username: Riverkeeper

Post Number: 659
Registered: 03-2005
Posted From: 170.141.68.2
Posted on Tuesday, December 12, 2006 - 10:24 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Chad,

I use Phosphoric Acid to acidify my sparge water also, but at a much stronger solution, its 35%. The mineral profile of my water is about the same as that of Munich, it takes about 1.5 mL of this strength to drop pH to well below 6.0.

If you add a little too much acid to the sparge water, no big deal. Really. Remember this, the pH of the sparge water may be very low, but there is not much in the sparge water that will react with the acid, buffer it in other words.

If you added the exact same amount of acid directly to your grain bed and mixed it in, you would probably be hard pressed to measure much of drop in pH. This is because there is a tremendous amount of minerals and other material for the acid to react with; it is buffered.

So add a few mL of your 10% acid, very weak by the way, check your pH with some cheapo strips, and if it is less than 6.0 sparge away. If you overshoot and it is much less than 6.0, its not a problem.

I know from experience this is not a problem because I WAY overshot the pH the first few times I acidified my sparge water. Also, a background in chemistry kept me in the RDWHAHB zone.

I am not a real chemist, meaning I don't make my income using that part of my education, but I agree with Bill on the 5.2 salts comment.

happy sparging.

Tim
 

Chumley
Senior Member
Username: Chumley

Post Number: 4466
Registered: 02-2003
Posted From: 63.118.227.254
Posted on Tuesday, December 12, 2006 - 11:07 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

>>I am not a real chemist, meaning I don't make my income using that part of my education,

wha-wha-WHAT?!? The great Doctor Wi, inventor/pusher of Star San?!? tranquil liza has proven this to be a FALSE statement.
 

KeepBrewing
Member
Username: Kb7

Post Number: 175
Registered: 05-2002
Posted From: 24.184.80.79
Posted on Tuesday, December 12, 2006 - 11:17 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

HANA makes a meter called "pHep" it is worth the money. Cost is some where between 70-80 bucks. You can then set you pH to 5.7 for the HLT and keep your mash in check between 5.0 to 5.5 pH.

As far as the HLT goes, under 5.7 pH and you leech out unwanted stuff from your mash and above 5.7 you do the same. The happy fulcrum point here is 5.7 pH. A great source for this info is in the book "Brewing Lager Beer" By Noonan
 

Bill Pierce
Moderator
Username: Billpierce

Post Number: 6045
Registered: 01-2002
Posted From: 24.57.224.220
Posted on Tuesday, December 12, 2006 - 11:42 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

The biggest problem with pH meters is that the mash is harsh on the junction in the probe and it tends to fail after a couple of years. Be sure you buy one with a replaceable probe (the dual junction probes are more expensive but last longer and are worthwhile if available for your meter). The cost of a replacement probe is typically $40-$50, which can be pricey unless you brew a lot. Another issue is that pH meters require frequent calibration with reference buffer solutions that go out of date. For those reasons I've come to prefer the high quality plastic coated strips. They, too, have an expiration date, but will last longer if kept in a cool, dry place.
 

Rob Beck
Intermediate Member
Username: Robbeck

Post Number: 302
Registered: 03-2003
Posted From: 65.64.102.30
Posted on Tuesday, December 12, 2006 - 11:58 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I always run my sparge water at 5.0 or slightly below and I've never had a problem leeching out unwanted stuff from my mash. The pH of my pre boil wort always comes out the same as the pH of the mash or one 10th of a point higher.
 

Sean Richens
Intermediate Member
Username: Sean

Post Number: 350
Registered: 04-2001
Posted From: 142.161.108.14
Posted on Friday, December 15, 2006 - 01:21 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Greg Noonan's The New Brewing Lager Beer has some formulas that work. I can't figure out why they work, they seem screwy, but they get the same answer as I do from first principles and agree with my pH measurements.

What you need to know is the water's alkalinity (by the standard method), its pH, and the concentration of your acid BY WEIGHT. You correct for the density after. If you get some chemist to work it out for you be sure they understand that you count phosphoric acid as having 1.5 hydrogens, not three (because the last hydrogen doesn't come into play until below pH 4). It gets pretty complex because the starting pH affects what form the alkalinity is in.

The good news is that you only have to work it out once unless you have bad seasonal variation, so borrowing a meter or pH strips is a viable alternative.

I use cheap paper strips, but I managed to find three narrow ranges that overlap between pH 5.0 and 5.5 which is equivalent to or better than the plastic strips - provided the user has nearly 30 years of lab experience.
 

Bill Pierce
Moderator
Username: Billpierce

Post Number: 6059
Registered: 01-2002
Posted From: 24.57.224.220
Posted on Friday, December 15, 2006 - 03:16 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

That's interesting, Sean. I'll have to take a look at the formulas in Noonan. I wonder where he got them. It should be mentioned that there can be considerable seasonal variation in the water in many locations, especially if the source is groundwater. I have lived in Des Moines, where Chad is from, and I can tell you there is a lot of difference especially in the fall and early spring. In my current location the Great Lakes are pretty much the same year-round.

(Message edited by BillPierce on December 15, 2006)
 

Tom Meier
Intermediate Member
Username: Brewdawg96

Post Number: 456
Registered: 03-2003
Posted From: 70.157.39.14
Posted on Friday, December 15, 2006 - 04:59 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

AJ Delange has a great article on this here HBD thing, that accounts for the different acid pK's (which define changing of acids H+ donor ions as the pH of the water changes)

I converted it into an excel spreadsheet that you can use if you know your water alkalinity is fairly constant. see my profile for link.

when I made the sheet, I remember finding that were several errors in the water chemistry section of the Noonan book..
 

Fredrik
Senior Member
Username: Fredrik

Post Number: 3511
Registered: 03-2003
Posted From: 62.20.8.114
Posted on Friday, December 15, 2006 - 10:49 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Ok I'll bite on this too, just for fun.

In theory you'd have to know what's in the water in order to find the buffering curves, but using the assumption that you just have a basic "carbonate system" as the dominating buffer one can make some guesstimates. I assume this is what is done in that book?

I have a multivariable pH sheet that I made long time ago and I plugged in your numbers as a test.

If I boldly assume that your water as is, is made up from dissolving limestone in water, and has pH 9.5 once can estimate the equivalent CaCO3 level in plain water you need to hit that pH. Then I put in the phosphoric acid (3 valued acid) into the same equations and compute.

This sheet I have (reservations for coding errors) fully accounts for all the various Pka's and pkb's in there, including the autoprotolysis of water.

My guesstimate, based on the above simplifications is that if you add

0.26 ml 10% phosphoric acid per gallon of water

the pH should go from 9.5 to 5.5.

But if your water pH was 10.0, I calculate that you would instead need to add 1.0 ml 10% phosphoric acid per gallon of water, 4 times as much!!

And OTOH, if you added that much acid into your 9.5 water, the water pH would drop to 3.7.

So FIW my blind guess from my number crunching would be that if your water is 9.0 - 10.0 my guess is that you need anything from 0.1 to 1 ml (PER GALLON) 10% phosphoric acid to bring the *water* to 5.5.

/Fredrik
 

Richard Nye
Senior Member
Username: Yeasty_boy

Post Number: 1902
Registered: 01-2004
Posted From: 68.4.202.69
Posted on Friday, December 15, 2006 - 02:44 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

In Noonan's New Brewing Lager Beer book on pages 72 and 73 he does the math to determine how much acid to add to adjust pH in water. But I agree it would be easier and more accurate to use a pH meter or test strips.
 

Denny Conn
Senior Member
Username: Denny

Post Number: 6069
Registered: 01-2001
Posted From: 140.211.82.4
Posted on Friday, December 15, 2006 - 06:19 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Yet another reason to batch sparge....I haven't had to worry about sparge water pH in over 8 years.
LIfe begins at 60...1.060, that is.
 

Tom Meier
Intermediate Member
Username: Brewdawg96

Post Number: 460
Registered: 03-2003
Posted From: 70.149.149.204
Posted on Saturday, December 16, 2006 - 12:17 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Denny, you have pretty good water.. I doubt all these brewers with problematic very high carbonate water can avoid high mash pH during sparge of a pils, even with batch sparging

its either use acid or cut with distilled.

I've no doubt your beer is good, and your procedures work, but they may not apply equally to everyone.
 

Kevin Davis
Intermediate Member
Username: Ktdavis98

Post Number: 422
Registered: 12-2003
Posted From: 152.163.100.8
Posted on Saturday, December 16, 2006 - 01:50 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I've been away for a while, when did the star rating system come back? Sorry this is off the topic.
 

Denny Conn
Senior Member
Username: Denny

Post Number: 6072
Registered: 01-2001
Posted From: 140.211.82.4
Posted on Saturday, December 16, 2006 - 05:26 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

No, of course not Tom, but I think it's more applicable than you imply. But batch sparging will still reduce your need to worry about sparge water pH, no matter where you start from.
LIfe begins at 60...1.060, that is.
 

Sean Richens
Intermediate Member
Username: Sean

Post Number: 353
Registered: 04-2001
Posted From: 204.112.139.135
Posted on Sunday, December 17, 2006 - 12:01 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Bill, I assume Noonan got the formulas at some German brewing school where he learned the rest of the lager stuff. For a guy whose other claim to fame is brewing Scotch Ales, in that book he almost writes with a German accent! The formulas are typical of chemists' procedures, with all of the assumptions buried deeply, which is why I can't figure them out. As an engineer, that bugs me.

Fredrik, there's nothing other than carbonate/bicarbonate with any buffering power in the pH range of interest unless your water supply has added phosphate for lead corrosion control, and that is minimal (1-3 ppm as phosphoric acid).

One other approach to not worrying about sparge pH is to use more malt and drop your efficiency. Like batch sparging, it keeps the last runnings up around SG 1.030 where you're not likely to extract much tannin or silicate.
 

Sean Richens
Intermediate Member
Username: Sean

Post Number: 354
Registered: 04-2001
Posted From: 204.112.139.135
Posted on Sunday, December 17, 2006 - 12:07 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Chad, this being your thread and all, I'd like to address your recirculation question. Six gallons of recirc? It doesn't matter what your batch size is, that's huge. How clear are you trying to get the wort? It doesn't have to be beer-clear. An absence of chunks is the minimum stage, a lack of suspended flour is good, but mere cloudiness is mostly proteins that will come out in the break. Only when I do a decoction mash do I continue recirculating until the wort is fairly clear.

One suggestion: if your mash tun is big enough for batch sparging, why not add the sparge water and NOT stir it in? Then you only have to recirculate once. Homebrewers don't have to care about efficiency, but colour is easier to hit if your efficiency is higher.
 

michael atkins
Intermediate Member
Username: Mga

Post Number: 486
Registered: 11-2003
Posted From: 71.214.30.107
Posted on Sunday, December 17, 2006 - 12:08 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I really hope that for "those", "me included" that have to screw around with our mash water dont have to go to extraordinary lengths to adjust the sparge PH.

And what are we adjusting here? The water PH? 7,8,0r 9-11, or some sort of relationship to "SRM" vs. "Residual alkalinity", like we do in the mash?
Love This Hobby!

http://msnusers.com/micksbrewery
 

Dave Coppes
Junior Member
Username: Pale_dave

Post Number: 34
Registered: 07-2006
Posted From: 24.91.216.6
Posted on Sunday, December 17, 2006 - 03:52 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I use a spreadsheet (John Palmer's http://www.howtobrew.com/section3/chapter15-3.html) to estimate how much to add. For my water it doesn't take much.

I then add slightly less than is estimated and measure with a pH meter. I keep adding and measuring incrementally so I don't over do it. By knowing the estimate from the spreadsheet you are less likely to overshoot.

My buddy and I bought a meter because we had mixed results from the strips. They aren't easy to read and are even harder when you are color blind!
 

Dave Coppes
Junior Member
Username: Pale_dave

Post Number: 35
Registered: 07-2006
Posted From: 24.91.216.6
Posted on Sunday, December 17, 2006 - 03:58 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Michael -

I only adjust sparge water pH. I shoot for 6.0 or below so the sparge pH doesn't go over 6.0

Mash over 6.0 (while sparging) is supposed to extract more tannins from the husks. Tannins = astringency which I don't like.

In many instances you can skip this step (obviously depends on you water and the batch you are brewing) and not have any problems.

Since it is so easy to do, though, I do it just to be sure.
 

Fredrik
Senior Member
Username: Fredrik

Post Number: 3515
Registered: 03-2003
Posted From: 213.114.44.230
Posted on Sunday, December 17, 2006 - 11:45 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

A general comment about the modelling/formula aspect: Except for trivial cases, most multivarible pH systems just can not be solved analytically in terms of elementary functions, because you end up with higher order equations. I've done it so I know.

So there are a couple of choices, old pre-computerage chem books used graphical methods to estimate pH from multivariable systems, but these days the preferred method would be to solve the equations numerically.

Or make some approximations which are quite good in many cases. About "approximations" there really isn't much to understand, except realizing that it is an approximation (numerical exploit) and not the exact solution (approximations tend to lack the natural logic and full asymptotic consistency that exact solutions have which is why there isn't much to understand really) and verifying that the approximation is valid - which often implies that you need to sort of work out the non-approximated model in order to work your way back to the approximation.

The way I'd try to "understand" the math is to try to work out the full, non-simplified equations because this is where the logic is, then re-derive the approximations, either from formula manipulations or by fitting simulation results to a simpler model.

The latter procedure is a method I often use for many problems, as it's easier than solving complex equations.

/Fredrik