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Old 01-16-2014, 01:47 AM   #1
bootney
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Default Need advice on target pH

Greetings,

I need some advice on what steps I need to take to better dial in my pH for a Hefeweizen I'm working on. I have brewed it twice and I plan to brew my third attempt again in February.

Below is the grain bill, water, salt and acid additions, calcium and magnesium levels of my water(without factoring in salt additions), and pH/gravity readings taken during my brewing process.

Grain bill
5.13# White Wheat (3.0 SRM)
4.62# Pilsen (1.8 SRM)
0.51# CaraPils (1.5 SRM)

Strike Water Volume and Additions
Total Volume: 5.40 Gallons
Total Alkalinity (as CaCO3): 29
Calcium: 30
Magnesium: 10
pH before treatment: 8.3
Phosphoric Acid 85% Addition: 0.40 mL
Calcium Chloride: 1.7 Grams
pH after treatment: 5.71
Mash pH after 5 minutes: 5.55

Sparge Water Volume and Additions
Total Volume: 3.90 Gallons
Phosphoric Acid 85% Addition: 0.20 mL
pH after treatment: 5.39
Boil Kettle Calcium Chloride Addition: 1.5 Grams

Final Runnings
pH: 5.80
Gravity: 1.012

Wort pH: 5.55
Wort gravity: 1.051

My question is do I add more acid or add more calcium chloride to lower the pH? My personal preference would be to use the acid to avoid altering my chloride to sulfate ratio which is balanced. So how much acid would be enough if that is the case?

Obviously my additions to lower pH weren't enough and after getting half way through Palmer/Kaminski's Water Book it looks like the "treatment" didn't do anything. I say that operating under the assumption that the DI pH of my malts (mostly base malts) listed above would yield a 5.5ish DI pH. Which essentially is what my mash resulted in.

Just looking for suggestions on ways to get the mash pH closer to 5.4, and wort pH closer to 5.2.

Thanks in advance for any suggestions.


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Old 01-16-2014, 02:40 AM   #2
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Mash pH drives the wort pH. Generally if you obtain an appropriate mash pH, the wort pH will be OK too. Of course, this assumes that the sparging water alkalinity is under 25 ppm.

Targeting a pH of 5.2 is appropriate in a Hefe since it is a tart and refreshing style. Another consideration is the acid type used. For German styles, using lactic acid will help present the nuances that the beer is known for. Phosphoric acid won't get you there.

That calcium content is somewhat low by ale standards, but is appropriate by Bavarian standards. High calcium content is NOT required for brewing. Calcium only helps with flocculation and reducing beerstone formation and is otherwise not needed in brewing.


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Old 01-16-2014, 05:37 AM   #3
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To determine how much extra acid you need I have to make some assumptions.

1) The base Pils malt you are using has the same buffering characteristics as Weyermanns pneumatic pils (DI mash pH 5.62 referred to room temp).
2) The wheat has a DI mash pH of 5.44 and linear buffering of -40 mEq/kg-pH
3) The Cara Pils has DI mash pH of 5.38 and buffering of -30 mEq/kg-pH

Based on those three assumptions (the first of which is quite reasonable and the other two of which are probably not too far from the truth) I get a predicted mash pH of 5.5 and a buffering capacity of 204 mEq/pH. Thus to drop the pH 0.1 pH you will need about 20 mEq of acid. To pH 5.4 85% phosphoric acid is 14.8 N (14.8mEq/ml) and lactic acid is 11.5 N (11.5 mEq/ml). Either will do. The tartness of Hefeweizen comes from the yeast, not the acid you use in the mash. Also, 5.4 is probably plenty low enough for mash pH. There is a pH that will produce the best tasting beer and it is somewhere in the range 5.2 - 5.5 with 5.4 - 5.5 probably being the best but, just as with any other parameter, you should brew at several different pH's in this range and see if it improves the beer or not. It is true that kettle pH will track mash pH closely but fermenter pH and final beer pH will be determined for the most part by the yeast, not what you do in the mash and kettle. Looking back in old logs from before the days when I started to take all this stuff so seriously with just tap water and no acid that my wheat beer mash pH's were 5.74 and 5.57 for two beers and the corresponding kettle pH's were 5.38 and 5.44. These pH's I would consider too high knowing what I know now. Nevertheless the yeast took the beers down to, respectively, 4.19 and 3.99. That 316 is powerful yeast. I remember those wheat beers - they were pretty darn good.
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Old 01-16-2014, 03:06 PM   #4
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With the first hefeweizen, I did use lactic acid due to that being the only option my local HBS. The first brew had a noticeable, but pleasant tartness to it. I used WLP300 and I know that tartness is characteristic of the strain but I wasn't sure how much of it was due to the yeast or the lactic acid. So when planning the second batch I did pick up the phosphoric acid for the sake of comparison. Both of the brews shared similar numbers from a pH standpoint.

A.J., when you mention adding 14.8 mEq/mL of phosphoric acid, is that the same as saying add 14.8 mL? The first time I have seen the mention of mEq (milliequivalents) has been while reading "Water" and I don't understand it's meaning when it's mEq/??. Also in factoring the estimated mash pH did you use the formula(s) from pages 96-98 in "Water"? Also what would the expected fermented pH range be for a hefeweizen?

Thanks again Martin and A.J. for all your help.
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Old 01-16-2014, 04:59 PM   #5
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Quote:
Originally Posted by bootney View Post
With the first hefeweizen, I did use lactic acid due to that being the only option my local HBS. The first brew had a noticeable, but pleasant tartness to it. I used WLP300 and I know that tartness is characteristic of the strain but I wasn't sure how much of it was due to the yeast or the lactic acid. So when planning the second batch I did pick up the phosphoric acid for the sake of comparison. Both of the brews shared similar numbers from a pH standpoint.
How about the taste? Did the one with the lactic taste any more tart than the one with the phosphoric or was the quality of the tartness any different? Knowing that German brewers use sauergut rather than phospohoric acid we are interested in knowing if lactate is an important part of the flavor profile of German beer.

Quote:
Originally Posted by bootney View Post
A.J., when you mention adding 14.8 mEq/mL of phosphoric acid, is that the same as saying add 14.8 mL?
I didn't say to add 14.8 mEq/mL. I said to add 20 mEq and that 85% phosphoric acid has acidity, WRT pH 5.4, of 14.8 mEq/mL. This means that you would need 20/14.8 = 1.35 mL of phosphoric. I also mentioned that 88% lactic acid has acidity of 11.5 mEq/mL but then put 14.8 in parenthesis by mistake which I'm sure didn't help you understand for which I apologize. Anyway it would take 20/11.5 = 1.74 mL of 88% lactic to supply those 20 mEq protons.


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The first time I have seen the mention of mEq (milliequivalents) has been while reading "Water" and I don't understand it's meaning when it's mEq/??.
A milliequivalent is 6.02E20 protons. They are dispersed (unless you are in a black hole) throughout some medium so that we refer to mEq per volume or mass. In the case of the lactic acid there are, effectively, 11.5 mEq in each mL so we write 11.5 mEq/mL. When talking about malt we usually refer to the amount by weight and thus write mEq/kg.

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Originally Posted by bootney View Post
Also in factoring the estimated mash pH did you use the formula(s) from pages 96-98 in "Water"?
I don't calculate RA but I do essentially the same thing. I guess I didn't come up with Proton Deficit until after the book had gone off to copy edit but certainly the germ of this concept is in there. An alkalinity is a positive proton defict and an acidity a negative one. In short I assume a pH and calculate proton deficits for the water's bicarbonate using the math behind Fig. 22 on p 96, for the pilsner malt using the data on Fig. 17 on p88, for other malts using assumed DI mash pH's and constant curve slopes as given in my last post, for phosphoric acid using the math behind Fig 36 on p121 and include negative deficits for calcium and magnesium based on Kohlbach's formula. I then use Excel's solver to adjust that assumed pH until the sum of all the deficits is 0. That's the estimated mash pH.


Quote:
Originally Posted by bootney View Post
Also what would the expected fermented pH range be for a hefeweizen?
Eric Warner describes several in his monograph and gives a pH range of 4.0 - 4.55 (with dunkelweizen at the high end, interestingly enough). The two value I found in my log last night (3.99 and 4.19) are consistent with that.
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Old 01-16-2014, 06:43 PM   #6
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Bavaria is where many hefeweizens are brewed in Germany. The water across most of that region is quite similar...hard and alkaline. The treatments available to brewers prior to the advent of RO were pre-boiling and lime softening. In both cases, the ability to neutralize the alkalinity is hampered by the somewhat low calcium content in those waters and the fact that calcium concentration cannot be reduced below about 12 ppm. So this leaves the typical Bavarian brewing water with around 100 ppm bicarbonate. In respect with the purity law, acid malt is used in Germany. For knowledgable brewers, lactic acid is used to achieve the same alkalinity reduction. Its unlikely that this amount of lactate will noticeably flavor the beer, but it should add a nuance that I feel is probably a component of German flavor. This beer is brewed with low calcium water.

Yeast is the major acidity producer in beer. But it is important to understand that minor increases in alkalinity that are reflected as slightly elevated pH in the mash are still echoed in the final beer pH. Hefeweizen is a tart style and the brewer MUST do their part to assure that the mash and final beer pH are in their proper range.

Thanks to AJ for pointing out the data from Warner. In some respects, I'm not surprised that the dunkelweizen is left with a slightly higher beer pH. My findings are that flavor is improved in darker beers with slightly higher pH. I assume that the brewers left the mash pH a bit higher to echo that pH into the finished beer.
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Old 01-21-2014, 12:34 PM   #7
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Thanks for the replies. Martin, I utilize Bru'n Water for all of my recipes, and when "Water" came out I decided to start using the municipal water supply. With that decision, I decided to monitor the pH at all stages to improve consistency. I used Bru'n Water to estimate the lactic(1st batch) and phosphoric(2nd batch) additions. I'll be honest, on the first batch I did not check the pH of the strike water, but I did check on the second batch and the pH of the strike water was 3.9. I had never checked the pH of the strike water prior to mashing in, so being in uncharted territories I dumped that water in fear that I made a mistake with either the amount of acid I added or made an error with my input into Bru'n Water. I redid the strike water and added 0.2 mL at a time until the strike waters pH was 5.7 and progressed with my brew day. Bru'n Water's initial suggested amount of phosphoric was 1.90 mL and A.J.'s suggestion was 1.35mL.

A.J., the beer with the phosphoric acid is still in primary. I will report back when able to for a comparison between the two.

I wasn't sure what the 14.8 mEq/mL represented in regards to how much acid, so thank you for clearing that up. I figured you wouldn't suggest adding 14 mL of acid but I didn't know how else to pose the question.
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Old 01-21-2014, 02:46 PM   #8
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Quote:
Originally Posted by bootney View Post
I wasn't sure what the 14.8 mEq/mL represented in regards to how much acid, so thank you for clearing that up. I figured you wouldn't suggest adding 14 mL of acid but I didn't know how else to pose the question.
Believe me when I say that I do understand how confusing some of this stuff can be. I have several times come up with what I think to be really clever ways of 'simplifying' these concepts only to find that they are great simplification to those that speak the language on a regular basis and utterly confusing to those that don't. Basically if you are in for a penny, you're in for a pound with the only alternative being the limited options of the Primer.
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Old 01-28-2014, 01:19 PM   #9
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I just sampled Hefeweizen 2.0(14 days post brew day) and the only thing I improved was the body/mouthfeel. I can't comment on the tartness of this beer (lactic vs. phosphoric) because the overall fermentation characteristics are muted with 2.0(was it the lactic acid or increased pitch rate that provided the increased tartness?). I was testing pitch rates with this style and 1.0 had 2x the pitch rate(increased tartness) at an estimated 350 billion cells and 2.0 had a normal pitch rate (muted dare I say bland?) at an estimated 175 billion cells(all estimates provided by yeastcalc.com). With 3.0 I will definitely go back to the higher pitch rate.

Getting back to the main topic of pH, the pH of the beer after fermentation was 4.01 at room temperature. February 8th can't get here soon enough so I can apply what I have discovered from this thread.
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Old 02-09-2014, 04:14 PM   #10
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So I had a chance to rebrew this beer yesterday after our discussion and here are the results(Recipe Unchanged from Above):

Strike Water Additions:
Total Volume: 5.40 Gallons
Total Alkalinity (as CaCO3): 29
Calcium: 30
Magnesium: 10
Untreated Water pH: 7.05
Calcium Chloride: 1.7 Grams
Phosphoric Acid 85% - 1.35 mL
Strike Water pH - 3.26

Sparge Additions:
Total Volume: 3.90 Gallons
Boil Kettle Calcium Chloride Addition: 1.5 Grams
Phosphoric Acid 85% Addition: 0.20 mL
Sparge water pH: 5.56

Mash pH: 5.43
Final Runnings pH: 5.80
Final Runnings Gravity: 1.011
Wort pH After Boil: 5.48

So I achieved the goal of lowering the mash pH to 5.4. Wort pH still above the 5.2 target at 5.48. I'm not sure if it is really that big of concern or not. I'll let you two chime in on the importance of trying to get the wort pH down to 5.2

Regarding my last post about the flavor profile of my second attempt with this brew, my pallet must have had a bad day is all I can say. The second attempt was far superior compared to my first attempt. Major difference being the second batch was pitched with an appropriate(estimated) pitch rate, and displayed the proper fruity esters I was targeting. I will say the second wasn't nearly as tart as the first. Once again not sure that first one was more tart due to double yeast pitch rate(experiment) or the lactic acid.

Thanks again for the assist on this brew you two.


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