The Great Bottle Opener Giveaway

Home Brew Forums > Home Brewing Beer > Brew Science > In process Ph numbers and how to adjust

Reply
 
LinkBack Thread Tools
Old 01-06-2014, 03:11 PM   #21
ajdelange
Senior Member
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: McLean/Ogden, Virginia/Quebec
Posts: 5,581
Liked 516 Times on 423 Posts
Likes Given: 14

Default

Quote:
Originally Posted by mchrispen View Post
So then I have a question about this...

The method described seems to deal with the buffering of the mash (grist) which has to be calculated or observed (test mash) to calculate the necessary acid/base addition, as well as titrating and diluting the total water bill to 5.4 pH.
What has been discussed in this thread is only the proton deficit (buffering) of the water.

Quote:
Originally Posted by mchrispen View Post
I assume the calculation of the grist acid addition (consider a negative value for alkaline requirement) is then added to acid required to A.) overcome the apparent alkalinity (carbonates and bicarbonates) and B.) dilute/acidify the total water volume to 5.4 pH (I assume at room temperatures as well).
Yes, a separate determination for the proton deficit of the grist is made and that added (though it can be a negative number if dark malt acidity overwhelms base malt alkalinity). Note that this determination is made using distilled water 'test mashes' (titrations) so that the malt proton deficit is decoupled from that of the mash water. The proton deficit of DI water is insignificant compared to the proton deficits of malts.

Quote:
Originally Posted by mchrispen View Post
It seems to me that we are adding unnecessary acid. Why acidify the sparge water portion to that extent as part of the whole water? If we acidify the whole volume to 5.4 and have the addition for the mash, then what happens when the volumes are divided for strike and sparge? It seems that the strike water will have a portion of the acid necessary to set the mash pH and the sparge will drive that pH further as it rinses the grains and ends up in the kettle.
Question is: what is the proton deficit of water that has been acidified to pH 5.4 with respect to a mash pH of 5.4. Answer: 0. OTOH if you do not acidify the sparge water it carries a proton deficit into the sparge and pulls the collected runoff pH up to higher than what it would be if you hadn't acidified the sparge water. Thus you are correct: more total acid added overall (in the entire brewing process) will result in lower wort pH than less overall acid added. But sparge water acidified to mash pH will not pull wort pH lower than mash pH when added to the mash during sparging.
__________________
ajdelange is offline
 
Reply With Quote Quick reply to this message
Old 01-06-2014, 03:26 PM   #22
mchrispen
accidentalis.com
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
mchrispen's Avatar
Recipes 
 
Join Date: Feb 2010
Location: Bastrop, Texas
Posts: 421
Liked 46 Times on 37 Posts
Likes Given: 45

Default

Thanks AJ - head hurts a bit since the mantra here has always been alkalinity and not pH in water, and here we are using an arbitrary pH of a very complex chemical and biochemical series of reactions. I do want to make sure I understand.

Just to summarize: the suggestion is to neutralize the alkalinity of the source water through acid treatment, then add additional acid to reduce that pH (which should be low at that point) to the target mash pH (5.4 in this instance), as well as an amount equal to bring a DI test mash to the same pH - so that all things are equal (pH and proton deficit). At this point, the proton deficit of the water is equal to the proton deficit of the mash - and consequently, the same is true for the sparge water.

Are we ignoring hardness in this process? or is that negligible? Meaning calcium driving phosphate reactions... where calcium is likely a significant ion in the water.

Forgive the questions - trying to work through this conceptually.

__________________
Matt Chrispen
Bastrop, Texas
www.accidentalis.com - blogging from the garage brewery
Bru'n Water Walkthrough
mchrispen is offline
 
Reply With Quote Quick reply to this message
Old 01-06-2014, 04:44 PM   #23
ajdelange
Senior Member
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: McLean/Ogden, Virginia/Quebec
Posts: 5,581
Liked 516 Times on 423 Posts
Likes Given: 14

Default

Quote:
Originally Posted by mchrispen View Post
Thanks AJ - head hurts a bit since the mantra here has always been alkalinity and not pH in water, and here we are using an arbitrary pH of a very complex chemical and biochemical series of reactions. I do want to make sure I understand.
The basic concept that when we look at water its pH isn't nearly as important as its alkalinity still holds for approximate work. The alkalinity number in a water report is the amount of acid it takes to get to end point pH (4.3, 4.4 or 4.5 for most labs). That is completely independent of pH. I can tell you the alkalinity without saying anything about the original sample pH. It is when you ask about how much acid it takes to get to a different pH, i.e. a mash pH, that I have to know the sample pH because I need to know how much total carbo is in the sample to do that.

Consider a water sample with alkalinity 100 and pH 9. Consulatation of the first curve in #7 shows that this water's carbo content is 1.8, Consultation of the second curve says that if we want to take pH 9 water with its charge of about -1.04 to pH 5.4 with its charge of -0.1 /mmol we need 0.94 mEq/mmol and with 1.8 mmol/L that would be 1.69 mEq/L.

Now consider water with alkalinity 100 and pH 6.5. The first chart shows carbo content of 3.5. But the second chart shows that the charge at pH 6.5 is -0.55 so that to get to pH 5.4 with charge -0.1 you only need an acid increment of 0.45/mmol which at 3.5 mmol/L amoints to 1.58 mEq/L. Thus for a given alkalinity there must be more carbo present at lower pH to support that alkalinity but at lower pH less charge difference must be made up for by acid. These two effects cancel by and large but not completely.

Quote:
Originally Posted by mchrispen View Post
Just to summarize: the suggestion is to neutralize the alkalinity...
Remember that we cannot speak of alkalinity without specifying a reference pH. We wish to neutralize (bring to 0) the alkalinity of the source water to 0 with respect to mash pH. The alkalinity, with respect to the lab's titration end point will not have been zeroed. If we 0 WRT mash pH and send a sample to the lab they will send back a report showing the original report's alkalinity minus the alkalinity of the water with respect to mash pH.



Quote:
Originally Posted by mchrispen View Post
...of the source water through acid treatment, then add additional acid to reduce that pH (which should be low at that point) to the target mash pH (5.4 in this instance),
If you have zeroed out alkalinity WRT mash pH then the water will be at mash pH. No further acid addition for the water will be necessary.

We wish to neutralize (bring to 0) the alkalinity of the source water to 0 with respect to mash pH. The alkalinity, with respect to the lab's titration end point will not have been zeroed. If we 0 WRT mash pH and send a sample to the lab they will send back a report showing the original report's alkalinity minus the alkalinity of the water with respect to mash pH.



Quote:
Originally Posted by mchrispen View Post
..as well as an amount equal to bring a DI test mash to the same pH
Additional acid will be needed in the mash in order to 'neutralize' (bring to 0) the alkalinity of the base malt with respect to mash pH. Some of this acid may come from the acidity, with respect to mash pH, of high-kilned malts.

Quote:
Originally Posted by mchrispen View Post
- so that all things are equal (pH and proton deficit). At this point, the proton deficit of the water is equal to the proton deficit of the mash
The sum of the proton deficits of each of the malts and the water is 0. The protons absorbed by the water and base malts just equal the protons given off by malt acids (and any we added).
Quote:
Originally Posted by mchrispen View Post
- and consequently, the same is true for the sparge water.
As it takes 0 acid to change the pH of water which has been adjusted to mash pH to mash pH its proton deficit is 0. Adding as much of it as desired to mash at that same pH will not change the pH of the mash.

Quote:
Originally Posted by mchrispen View Post
Are we ignoring hardness in this process? or is that negligible? Meaning calcium driving phosphate reactions... where calcium is likely a significant ion in the water.
In this thread we haven't talked about it but it is definitely involved. The definition of residual alkalinity makes it clear that 3.5 mEq of calcium or 7 mEq of magnesium release 1 mEq of acid. How true that is in the universe of brewing situations I don't know but until I do some experiments to check that out that's what I am using for calculations.
__________________
ajdelange is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2014, 11:36 AM   #24
maplemontbrew
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2013
Posts: 84
Default

Quote:
Originally Posted by mabrungard View Post
Yes, you can. But most who have tried this blindly, found that they overshoot the acid addition. Because of the interaction of pH and alkalinity, the water pH barely changes during the early acid additions (small) because the water's alkalinity is being consumed. The pH drops like a rock when the alkalinity is gone.



Therefore, having a good idea of the proper acid amount is a safer way to perform acid additions.

Is it best then that you wait a while, say 15 minutes or so, to test ph after the acid addition?
__________________

Kentucky Ebrewer. Hefeweizen is my first love!

maplemontbrew is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2014, 12:51 PM   #25
mabrungard
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2011
Location: Carmel, IN
Posts: 2,631
Liked 174 Times on 152 Posts
Likes Given: 24

Default

Quote:
Originally Posted by maplemontbrew View Post
Is it best then that you wait a while, say 15 minutes or so, to test ph after the acid addition?
Well, that might help. But that is a long time to allow the pH to be off target.

My experience is that we add a little acid and check pH, and again and again. Since we are concerned about overshooting the acid addition, the additions were small and the pH did not shift very much due to the alkalinity effect. Then you increase the addition amount after a couple of trys and end up overshooting anyhow.

Waiting and measuring is OK when you have a decent idea of the total acid amount needed and you are then just fine tuning with a bit more. But the hunt and peck method can be a frustrating approach.

Math and science are nice tools most of the time.
__________________

Martin B
Carmel, IN
BJCP National
Foam Blowers of Indiana (FBI)

Brewing Water Information at:
https://sites.google.com/site/brunwater/

Like Bru'n Water on Facebook for occasional discussions on brewing water and Bru'n Water

mabrungard is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2014, 01:18 PM   #26
ajdelange
Senior Member
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: McLean/Ogden, Virginia/Quebec
Posts: 5,581
Liked 516 Times on 423 Posts
Likes Given: 14

Default

I think we are confusing water and mash. When treating just the water the reaction should be complete and a pH meter reading settled in a couple of minutes. In a mash it is a different matter and you may have to wait some time before the effects of an acid addition are seen.

__________________
ajdelange is offline
 
Reply With Quote Quick reply to this message
Old 01-09-2014, 02:09 PM   #27
cervid
Registered User
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2013
Posts: 215
Liked 8 Times on 7 Posts
Likes Given: 4

Default

Quote:
Originally Posted by maplemontbrew View Post
Have you tried any other spreadsheets with which to compare Bru'nWater. I looked at this and sounds pretty good.
Bru'n is the best I've used or messed with. All the others lack something. It may take a day to get familiar with it, but everything is there.

I used Martin calculations on his site that I originally overlooked and he was nice enough to point out regarding boiling water to reduce HCO3 and Ca. I just used his sheet and did a 'save as' for tap water and boiled tap water.

For each new style you do, you can play with both files, get the numbers right, then do another 'save as' for something like 'style x tap water boiled', etc.

You really can't beat his sheet.
__________________
cervid is offline
mchrispen Likes This 
Reply With Quote Quick reply to this message
Old 01-20-2014, 02:05 PM   #28
maplemontbrew
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2013
Posts: 84
Default Mini mash

Quote:
Originally Posted by ajdelange View Post
I think we are confusing water and mash. When treating just the water the reaction should be complete and a pH meter reading settled in a couple of minutes. In a mash it is a different matter and you may have to wait some time before the effects of an acid addition are seen.
I am planning to do a 1/8 scale min mash where I would bring my water to the proper Ph using lactic acid then add the scaled down grain bill to measure its effect on the base water Ph. Does that sound like a pretty good process?
__________________

Kentucky Ebrewer. Hefeweizen is my first love!

maplemontbrew is offline
 
Reply With Quote Quick reply to this message
Old 01-20-2014, 04:08 PM   #29
mchrispen
accidentalis.com
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
mchrispen's Avatar
Recipes 
 
Join Date: Feb 2010
Location: Bastrop, Texas
Posts: 421
Liked 46 Times on 37 Posts
Likes Given: 45

Default

If you are planning to go below the proper pH, as the malt bill will tend to add acid, then yes. You may then need to add alkalinity, since you cannot take back the acid addition, to counter the net lower mash pH. If you could estimate the acid contribution of the grist (see Bru'n Water or AJ's spreadsheet), then you could calculate backwards to a strike water pH (assuming alkalinity has been removed). So if the grist contribution is equal to X meq/L, and the acid required to lower the liquor to 5.4 is Y - then you would titrate your liquor to Y-X and minimize the need to add alkalinity that would otherwise not be needed. I am happy to be corrected, but this seems logical to me.

A test mash, at least for me, serves to test my recipe, mineral additions, and track mash pH. That said - it is VERY hard to get dry milligram measurements correct, at least liquid acid can be added with CC scaled syringes. Consider concentrated solutions for gypsum and calcium chloride. I generally only make a single adjustment (if required) with a pre-calculated amount of acid or base in a test mash. This gives me excellent data on what will happen at scale in my brew house... and I can make any adjustments necessary before - while verifying pH during the mash. Added bonus - boil the test mash wort for a starter!

Acidifying the strike liquor to the target mash pH seems confusing (to me) as you will most likely overshoot the mash pH when introducing the liquor to the malt phosphates (usually a net acid scenario), especially with crystal or dark roasts. Maybe if you were simply removing alkalinity - easier to calc meq/L acid to counter meq/L bicarbonate for example... but then why not traditional slaking, boil/decant and/or dilution with RO or DI?

__________________
Matt Chrispen
Bastrop, Texas
www.accidentalis.com - blogging from the garage brewery
Bru'n Water Walkthrough
mchrispen is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Numbers and process Clementine All Grain & Partial Mash Brewing 5 08-27-2011 01:58 AM
recipe kit OG numbers vs. beer calculus numbers borealis Beginners Beer Brewing Forum 3 02-11-2010 08:56 PM
Can I adjust My SG? Jlenigk17 General Techniques 4 10-15-2008 06:31 PM
How do you adjust for old hops? stever General Techniques 5 04-02-2008 09:53 PM
Numbers numbers everywhere! My efficiency is??? Zymurgrafi All Grain & Partial Mash Brewing 40 12-14-2007 12:22 AM