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Old 01-12-2014, 11:24 PM   #1
monkeyman1000
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Default Could use some advice, please

I brewed a Scottish Ale today. I'm using RO water and Bru'n water. This is my second brew using the above and my pH meter. I was trying to hit about 5.5 each time but come up with 5.3. I measured at 20' and got 5.31 at 70.3 degrees. Again at 30' with pH 5.33 at 73 degrees and again at 40' with pH 5.29 at 73 degrees. This was about the same results with my amber ale. I guess I just shoot for a pH of 5.7 on Bru'n water next time to hit 5.5.
Also, I noticed a 4 degree difference in temp from my pH meter and my Thermapen. I calibrated my Thermapen about 3 months ago and it was spot on. I will redo it tomorrow. Is this a big deal if the pH meter is off on temp? Thanks for the help.
Oh, one more question. I calibrated my pH meter about 30 minutes before my first reading. It stabilized at 7.01 in buffer 7.0 at 69 degrees and in the 4.01 buffer it stabilized at 4.06 at 71 degrees. I waited about 7 minutes for each buffer. Do I need to add/subtract anything from the mash pH numbers I got above? Thanks again.

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Old 01-13-2014, 04:52 AM   #2
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I brewed a Scottish Ale today. I'm using RO water and Bru'n water. This is my second brew using the above and my pH meter. I was trying to hit about 5.5 each time but come up with 5.3. I measured at 20' and got 5.31 at 70.3 degrees. Again at 30' with pH 5.33 at 73 degrees and again at 40' with pH 5.29 at 73 degrees. This was about the same results with my amber ale. I guess I just shoot for a pH of 5.7 on Bru'n water next time to hit 5.5.
It's reasonable to expect differences between predicted and observed pH of this magnitude. Brun't water doesn't know anything about your malts except perhaps their color. Tell us about your water (alkalinity, hardness and pH) and the amounts of each malt and what it is (type, color) and the amount of mash water and we can look at individual proton deficits which may give some insight as to why what you see and what you expect differ. Note that I won't know anything more about your malts than what you tell me so any prediction I do is equally iffy but the model is robust and sometimes yields clues.

You can't assume that if you take shoot for 5.7 in the model that the observed pH will go up by that same amount. Part of the problem is in getting buffering capacities wrong and they have to be about right for your idea to work.


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Also, I noticed a 4 degree difference in temp from my pH meter and my Thermapen. I calibrated my Thermapen about 3 months ago and it was spot on. I will redo it tomorrow. Is this a big deal if the pH meter is off on temp? Thanks for the help.
Thermapens use Type K thermocouples - not known for high accuracy. Thermapens are great for barbequing - not so great for mashing beer. The pH meter has, presumably, an RTD as they are appreciably more accurate but they are not perfect either. Until you check them both against a lab grade thermometer I'd trust the pH meter more than the Thermapen.

To answer your question: small errors on the part of the pH meter temperature measurement won't make much difference but larger ones will. The spec on your meter implies that it has to measure temperature to 0.5 °C or better.


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Oh, one more question. I calibrated my pH meter about 30 minutes before my first reading. It stabilized at 7.01 in buffer 7.0 at 69 degrees and in the 4.01 buffer it stabilized at 4.06 at 71 degrees. I waited about 7 minutes for each buffer. Do I need to add/subtract anything from the mash pH numbers I got above? Thanks again.
I'm not entirely clear on what you did here but it doesn't matter if during calibration the indicated pH of a buffer is off by as much as 0.06. The electrode does drift over time and that is why you do calibration. If, OTOH, you do a calibration and then check the buffer pH and it is off by that much then you have a problem. The calibration was not successful or the meter is very unstable.

You don't really have to do a calibration. You can check the buffer pH's at 7 and 4, determine the errors at those 2 pH values and apply the average to any subsequent readings (as mash pH is about half way between 4 and 7) but all readings must be done at the same temperature. The reason for having calibration features is so that you don't have to do that.
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Old 01-13-2014, 06:00 AM   #3
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Thanks for the reply Ajdelange, I will try to be more in depth in the future.
For the Scottish 80 I brewed today (from Zainasheff and Palmer's book) the grain bill was
Marris Otter 3.14 pounds - 4.5 Lovibond
Munich 10 .17 pounds - 10 Lovibond
Crystal 40 .33 pounds - 40 Lovibond
Honey Malt .17 pounds - 18 Lovibond
Crystal 120 .08 pounds - 120 Lovibond
Chocolate Malt .06 pounds - 350 Lovibond
I am using RO water from the local food COOP but haven't had it tested. I used the default RO profile in Bru'n Water and added 1.2 grams of Gypsum, 1.7 grams of CaCl2 to 3.45 gallons of water.
Bru'n water calculated the following
Ca 58.5
Mg 0
Na 8
Sulfate 52.6
Cl 67.8
Bicarb 16
Total Hardness 146
Alk 13
RA -29
Mash pH 5.50
I use BIAB with no sparging.
That sucks about the Thermapen, that is what I am using to check my mash temps. I don't suppose a lab grade thermometer is cheap?
My question regarding the calibration was based on another post I saw you answer. I have the Hach Pro+ and have done a stability test on it which you were nice enough to verify for me as being stable. I wasn't sure if I was supposed to take the average of the +.05 with the 4.01 buffer ( 4.06 is what my meter stabilized at in the 4.01 buffer) and the +.01 ( my meter stabilized at 7.01 in the 7.0 buffer ) which would be [(+.05 plus +.01 )/2] and add or subtract that back to my mash pH readings. I used the automatic calibration mode when doing the calibration step. Wasn't sure if I needed to doing anything else after that.
Thanks again for the help.

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Old 01-13-2014, 02:01 PM   #4
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In a grist like this where the base malt comprises 80% of the total it is the base malt that drives mash pH. The only other player with anything like equal influence is the large calcium concentration which is enough to change the mash pH by 0.13 (IOW if you took out half the calcium the pH would go up by about 0.065). I have, as I said, to make a lot of assumptions about the malts you used based on their broad characteristics. For example, you used Maris Otter. There are several maltsters that produce malt from that strain and I haven't measured any of them. If I assume that MO behaves like Weyermanns Pils (which has a DI pH of 5.622 - reports on MO are about the same) and that the chocolate malt you used behaves like a chocolate malt I measured and that the other malts you used have linear buffering with values that are the same as the average values measured by Kai Troester I estimate 5.414 for the pH of the mash you describe. This is about half way between what Bru'n predicts and what you observe. My prediction is within 0.1 of what you observe and, given all the problems with predictions, has to be considered a pretty good one.

You mustn't conclude from this that AJ's spreadsheet is better than Bru'n water even though it may be better in this case. You should conclude it is different. It might be illuminating to try some of the other spreadsheets. You will get different answers from them too. They also use different models. The AJ model is very robust when fed good malt data but a good data set on a single malt takes me a couple of days in the lab. When I have to say 'MO is about like Weyermann's Pils because I've seen people post that MO's DI mash pH is about the same' then all that robustness flies out the window.

Nevertheless it can show us some things. Lets assume that the MO you used has a DI pH of 5.600 (as opposed to 5.622) but that it's buffering characteristics are the same as weyermann's. That shifts the pH prediction to 5.396. A change in base malt DI mash pH of 0.022 leads to a change in predicted mash pH of 0.018. This is why we say the base malt is in charge here.

I'm still not clear on exactly what you are doing with the cal. You should rinse and blot and place the electrode in pH 7 buffer. The meter will, at this point, read some number close to but not necssarily equal to 7. That number may shift a bit as the bulb gets wetted with the buffer and the glass comes to equilibrium with it. That number should settle after a minute or two so it is a good idea to wait a few minutes at which time the button is pressed and the cal reading accepted. This is confirmed by the reading flashing three times. Now rinse and blot and put in the 4 buffer. The same thing should happen but it usually takes longer to equilibrate at 4 as you are coming from 7. When the 4 reading is stable, press the button again to accept that reading (again confirmed by the flahing) and then press and hold to end the cal. Now the cap is still filled with 4 buffer and the meter had better read 4 or close to it with the actual value depending on the temperature. Assuming the temperature is such that the buffer is actually at pH 4 the meter should read 3.99, 4.00 or 4.01, IOW the least significant digit will probably toggle. It should not read 3.95 or 4.06. It is OK for it to read 4.06 in 4 buffer before calibration. It is not OK for it to read 4.06 after calibration. You do the calibration to take out the 0.06 error which is a result of electrode drift between uses. As your stability test showed the readings in 4 buffer will eventually wander off and when they do it is time to recalibrate. This is why the meter shows you the cal reminder annunciator after 3 hours.

If you have a Hanna meter, for example, which grabs the cal reading before it is at equilibrium, you will not be able to get a good cal and the meter will read something off 4 and something off 7 in both buffers. In that case you can compensate by removing the average error from sample readings. You should not have to do that with the Hach meter. If you cannot get a good cal on it when it is this new you should seek warranty relief.

I should probably point out that it is normal for a new user to encounter things that don't quite seem right with an instrument he has not used before. You can't expect to pick up a Strad and play the Partitas right off. The pH meter isn't quite so demanding but there is a learning curve.

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Old 01-13-2014, 04:09 PM   #5
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Thanks for the reply Ajdelange, very helpful. I am doing the calibration like you describe and the readings I listed are what I got before I accepted the numbers. I wait a good 7 minutes. But now that you mention it, I never look at the number after I accept the value. It does flash 3 times but I never looked at the value it gives after that. DUUUUHHHH!! Chalk that up to learning.

The mash pH I got was at least in an acceptable range so I will be happy with that. It is also fermenting away nicely this morning so beer is being made.

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Old 01-13-2014, 04:31 PM   #6
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Ajdelange

What is the best calculator to use in your opinion? for mash and water ?

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Old 01-13-2014, 06:15 PM   #7
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What is the best calculator to use in your opinion? for mash and water ?
My own, of course!

Being a little more serious about it the first question is how do you define best? One answer might be the one that gives the closest predictions of mash pH. But how would we determine that? We'd have to do a collaborative experiment in which 1000 brewers used each of the candidate calculators on each of many styles of beer, collate and interpret the data and make a recommendation. This isn't going to happen.

I'll assert, without fear of contradiction, that my spreadsheet for mash pH uses an algorithm that is more robust than any of the others of which I am aware. But as I pointed out previously it has to be fed with accurate data and that data is very hard to get. If you have to guess at what malt properties are in order to use this spreadsheet you are probably really no better off using it than any of the less robust ones.

Turning now to my water spreadsheet - it is again very robust. It considers the effects of ionic strength, calculates the saturation indices for carbon dioxide and calcium carbonate, allows you do design phosphate (or other buffers), considers the change in equilibrium constants with temperature, calculates solubility for any of the three crystaline forms of chalk and facilitates mmse synthesis of an arbitrary ion profile from any water using salts and any dilution water. Do you care about any of those things? Are you willing to slog through a 55 page manual in order to learn to use it? It is elegant. Is it better?

IOW I can't answer your question and even if I could I wouldn't. Some pretty talented people have worked pretty hard to produce the calculators I am aware of and while they all have shortcomings there are no major ones. I think you will have to decide for yourself.

No calculator should be used in the place of actual measurements on the mash, beer and water. They are great for guiding you, letting you see what the effects of doubling the chocolate malt might be etc. but in the end you have to tweak and brew, tweak and brew, and tweak and brew again until you hit the sweet spot.
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Old 01-13-2014, 06:39 PM   #8
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Default Could use some advice, please

If I were to start with a basic one for water quality purposes is there a list or FAQ?

Where would I find yours?

One other basic question,
What metals do I not want on my water?

I assume Fe is a big no? Will an iron curtain (bubble column) remove too much of the good minerals? My well is an artesian here in Mid East WI (flows over near year around)

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Old 01-13-2014, 07:06 PM   #9
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If I were to start with a basic one for water quality purposes is there a list or FAQ?
Do searches on Bru'n Water, Brewer's Friend, EZ water...

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Where would I find yours?
www.wetnewf.org but you do not want to start out with my stuff.

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One other basic question,
What metals do I not want on my water?
Obviously things like mercury, lead, arsenic, cadmium... they represent health hazards but iron, manganese and copper are also potenitally problematic in terms of flavor.


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I assume Fe is a big no? Will an iron curtain (bubble column) remove too much of the good minerals?
Although the EPA aesthetic limit for iron is 0.3 mg/L most brewers would agree that 0.1 is the upper limit. An 'Iron Curtain' (clever choice of name) should take care of that but you would want to do a simple test to see. If the water out exceeds 0.1 mg/L then try increasing the air exposure time.
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Old 01-13-2014, 07:36 PM   #10
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If I were to start with a basic one for water quality purposes is there a list or FAQ?
A couple of additional places to start:
1.) Read through the sticky primer. It is really the best starting point as you learn the process (or art) of managing your mash pH with acid/base and a calibrated pH meter for a specific beer style. I cannot emphasize enough how important it is that you are comfortable with the measurement tools and calibration - and the primer process is safe enough for that for a few brews.
2.) The Palmer/Kandisnky Water book is an excellent introduction into water chemistry - and AJ there (as well as Martin) consulted on the book. AJ's thinking has advanced past some of the theory in the book - but again - good starting point if you are interested in advanced approaches.
3.) The Bru'n Water knowledge page is a great survey of the basics of water chemistry and application - https://sites.google.com/site/brunwater/water-knowledge
4.) The spreadsheets that AJ mentions are good - EZ water pH predictions tend to be hit and miss for me but very easy to use. I use and prefer Bru'n Water spreadsheet, and have learned a lot using it, and have found the predictions reliable. And there is Brewer's Friend tools if you prefer an online approach (I have used it once, and prefer the spreadsheet format). Your mileage may vary (likely based on the calibration and skill with a pH meter). All calculate their mash pH predictions differently - so expect some disagreement. AJ is spot on about predicting mash - so verify - verify - verify.

There are both very scientific/engineering approaches and application oriented approaches to water chemistry. You really don't NEED to understand chemistry to use it to your advantage, but in dealing with critical thinking scenarios it is very helpful, but the basics are necessary (proper weighing of salts, mash pH monitoring). If you are very good at math and chemistry (I am numerically challenged), there is a solution here. Otherwise, you can rely on the spreadsheets while verifying (please verify) in the brew house that what you wish to occur - is happening... which is to get the mash pH correct first and the flavorings correct.

Keep reading advice here from folks like AJ, Martin, etc. - they are a fonte (a pun for AJ) of knowledge and application, and responsible (IMO) for helping me address some major issues in my brewing.
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Last edited by mchrispen; 01-13-2014 at 07:38 PM. Reason: clarity
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