lockwom

Recipes 

I double-checked with color pHast strips. Not the most reliable, but they validated my measurement when accounting for bias.

The water had plenty of calcium. And I did make measurements within the unstable period you mentioned.

BW estimated my protein rest pH to be 5.3 (fine for proteolytic enzyme range) and mash pH as 5.5.

I could have:
- mismeasured salts
- faulty protein rest pH measurement
- bad sensor

I don't have enough recorded data to challenge the model, nor enough evidence that it was not my fault. But I just wanted to mention the worthiness of having lime on hand, since properly estimating pH for the different malts is hard.

My original suspicion was that the model underestimated the crystal contribution.

mabrungard

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I haven't seen crystal malts that contribute more acidity than what the model predicts, but I have seen base malts that contribute more acidity than expected. Rahr malts seem to have this tendency. I assume they slightly acidify their malts and most brewers appreciate that since many have excess alkalinity they have to deal with.

Since this was a No-Sparge brewing case, I would have assumed that the pH value would have biased a little high and not low. I'm still scratching my head on this one.

__________________
Martin Brungard, P.E. D.WRE
Carmel, IN
BJCP National
Foam Blowers of Indiana (FBI)

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

Kaiser

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What was the calcium content and/or RA of the water you added?

Kai

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BrauKaiser.com - brewing science blog - Twitter - water and mash chemistry calculator

Hermit

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I have wondered if they have a specific large client that they cater to in this regard.

lockwom

Recipes 

Calcium was 51 ppm, and Mg was 5 ppm. I calculate the water had RA of -6, seemed fine for an ambery beer.

Here is what I suspect went wrong: I added the pickling lime for that batch to the mash liquor before heating it. I'm sure it was readily dissolved, but perhaps some of the pickling lime content precipitated when heated combined with some calcium content (that is, not sure it was HCO3 at the higher grain-less pH, but I still bet it it left the solution).

I've since added pickling lime to a batch with acidic grains directly after adding grains with very reliable results. But I'm not ruling out some form of mismeasurement. I'm planning on brewing a porter tomorrow, so I will try to verify my process. How long should I wait to measure pH after adding the pickling lime?

Does my explanation above sound plausible?

(Also, there was some Rahr 2-row and Weyermann Munich I in there, it could have had more acid than the "Base Malt" model in BrunWater). This year, I bought CMC 2-row to see how it compares to last year's Rahr.

lockwom

Recipes 

Even with 0.6 lbs of roasted malts, Kai and Martin's spreadsheets predicted the mash pH. Lesson learned, add the pickling lime to the mash after adding the grains.