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Old 09-03-2014, 12:54 PM   #21
ajdelange
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Originally Posted by CadiBrewer View Post
What I have is called Mrs. Wages Pickling Lime and the only ingredient listed is calcium hydroxide. I can only assume what I have is correct.
The fact that it fizzed says that there is a fair amount of calcium carbonate in there.

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I have more data and it isn't helping me figure out the problem. I figured my lime was bad, so I went forward with a rebrew on Sunday of the same beer, except I refigured my salts with baking soda instead of lime.
I'm not really sure you have a problem.



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I mashed in, stirred like crazy, and checked the pH at 5 minutes. Instead of 5.45 as predicted in Bru'n Water, it measured, wait for it, wait for it, 5.19!?!?!?! I'm totally lost now. I waited until minute 20, checked again, and it was 5.19. I added .9 grams of baking soda for kicks and giggles, and ended up at 5.23.


Tonight I checked the pH of my three malts in RO water. I used a coffee grinder to grind 40 grams of each of the malts, and mashed them in 100 ml of water for about 15 minutes. The Maris Otter came out at 5.54, the crystal 55l came out at 4.60, and the chocolate malt came out at 4.49.
If I take your DI mash pH's and assign buffering capacities at the low ends of what I have actually measured for similar malts I get a mash pH prediction of 5.22 which isn't that far off from what you observed. Furthermore, if I add the 0.9 gram of bicarbonate I get an estimate of 5.28 which is 0.06 higher and that compares more or less to your observed increase of 0.04.

Of course I can get any answer I want by jiggling the numbers that model the malts but at least the DI mash pH number is solid.

The 'problem' that you are experiencing is that Bru'n water doesn't model the malts you are actually using very well and it can't possibly as it has no place for you to enter the actual malt parameters. My spreadsheet doesn't model the actual malts you are using very well either because while it has a place for the actual malt parameters to be put in I don't have 3 of the four - only the DI mash pH - parameters required. To get these 3 you would have to do a much more extensive set of measurements on each of the malts. The procedure is spelled out at http://wetnewf.org/pdfs/estimating-mash-ph.html (you have to read down to the end) and if you check this out I think you will conclude that a test mash is a much easier way to go.


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Originally Posted by CadiBrewer View Post
I checked my meter in 4.01 calibration solution between each test and it hit 4.01 or 4.02 each time.
Good practice but by now you should have gained confidence in your meter.


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Can someone shed some light on where I might be going wrong?
I hope I have. In summary, I don't think you are going wrong other than in expecting a spreadsheet to come up with an accurate prediction. Often they do but sometimes they don't. People need to understand this.
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Old 09-03-2014, 12:54 PM   #22
mabrungard
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Another brewer recently performed a test of how well he could distribute water additions when they were added to the mash. He confirmed by collecting pH samples via a long pipette and temperature checks with a long stem thermometer that regardless of how well he stirred the mash, there were still variations.

This is one of the strongest reasons why I recommend that brewers add all of their minerals and acids to the mashing water BEFORE adding the grist. This enables the brewer to completely mix and distribute those components into the water COMPLETELY. Don't listen to anyone that says that minerals like gypsum or calcium chloride don't dissolve well in water and that you should add them to the mash. Wrong! Those minerals are COMPLETELY soluble in water at the typical concentrations we brewers use. It may just take a few minutes for them to fully dissolve. Keep stirring and they will dissolve!

The mineral that might be questionable for adding to the water before the grist, is lime. That is because of its ability to raise the pH very high and cause calcium in the water to precipitate out of solution as chalk. That is not a good thing. However, if you are starting with low alkalinity water, it probably also has little calcium. You might be able to get away with adding the lime (or a portion of it) to the water prior to adding the grist and having a better distribution of its ions in the mashing water.

I have to admit that I add my lime to my mash after adding my grist. However, I use a RIMS and the flow of wort through the grist is very effective at mixing and distributing the ions throughout the mash. For brewers using a static mash, one option is to vorlauf the wort through the mash for a few minutes to help distribute the ions more evenly. Doing that step in addition to mixing may help avoid incomplete distribution of the minerals.

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Old 09-03-2014, 03:37 PM   #23
CadiBrewer
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Thanks Martin and AJ for the patience and the help. Test mashes from here on out for new (to me) recipes.

One last question - Because I have been so confounded by this particular mash, I scoured my inputs on Martin's spreadsheets to make sure there wasn't a data entry error. When I was playing around with the water additions, I noticed that specifically for the sodium column, the amounts in the Water Additions area in ppm don't add up to what is above in the finished water profile ppm. The other mineral additions all add up. Is that correct or do I have a bug in the spreadsheet?

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