Bru'n Water Using 100% Dilution

[kcbeersnob]

For the heck of it I decided to brew a batch with 100% distilled water and build the water profile from scratch using the water adjustment tab in Bru’nWater. Instead of editing the water profile, I just set the dilution level to 100%. My predicted mash pH was 5.35. Actual pH was 5.02.

This is the first time my pH has been off by that much. Perhaps I used the wrong approach by setting the dilution ratio to 100% instead of configuring the water profile?

My pH meter is calibrated and I’m confident in all of my measurements.

Any thoughts?

[mabrungard]

That is the way I do it when I’m testing things out. Just dial up the dilution to 100%. That ratios the ion content to the selected water RO or distilled. If using distilled water, the Diluted Water profile should read zeros all the way across.

Are you sure that there wasn’t some other acid source in the mix? To drop the pH as low as you recorded, there would have to be a decent amount of darker crystal or roast malt in the grist, or the amount of calcium added would have to be high.

I’m surprised that the actual result was lower than the prediction. Both Kai and AJ say that there is no way that Bru’n Water is correct since it predicts a LOWER pH than their models. This result is therefore opposite of the trend that Bru’n Water typically provides. There has to be some difference between the modeled conditions and the actual conditions.

[silentknyght]

[quote=“mabrungard”]

I’m surprised that the actual result was lower than the prediction. Both Kai and AJ say that there is no way that Bru’n Water is correct since it predicts a LOWER pH than their models. [/quote]

I have a lot of anecdotal evidence (data?) which supports this; good to hear it isn’t a fluke.

To the OP: the only thing I can think of is a bad calibration on the pH probe. I’d verify your meter’s calibration/accuracy using clean reference solution.

[hades]

Does Bru’n Water factor distilled water pH as 7.0? I have been curious about this myself, as I’ve read that distilled water pH will likely be below 7.0 due to carbon dioxide being introduced from the atmosphere, making most grocery store distilled water somewhere between 5.0 and 7.0? That said, I’m no chemist and this is just something I’ve read a few times on the net.

[mabrungard]

Water pH is almost meaningless in mash chemistry. It is the alkalinity of the water that matters. The pH of RO or distilled water is likely to be less than 7 when its in contact with air. It still doesn’t affect mash pH.

[kcbeersnob]

[quote=“mabrungard”]That is the way I do it when I’m testing things out. Just dial up the dilution to 100%. That ratios the ion content to the selected water RO or distilled. If using distilled water, the Diluted Water profile should read zeros all the way across.

Are you sure that there wasn’t some other acid source in the mix? To drop the pH as low as you recorded, there would have to be a decent amount of darker crystal or roast malt in the grist, or the amount of calcium added would have to be high.

I’m surprised that the actual result was lower than the prediction. Both Kai and AJ say that there is no way that Bru’n Water is correct since it predicts a LOWER pH than their models. This result is therefore opposite of the trend that Bru’n Water typically provides. There has to be some difference between the modeled conditions and the actual conditions.[/quote]
Thanks Martin! Glad to hear I used the right approach. Calcium and dark grains were both somewhat modest.

The water amendments (3.55 gal mash volume):
Gypsum: .7g
Epsom salt: .9g
Salt: .4g
Cal. Chloride: 1.6g

Grist for 3.5 gal batch:
MO: 7 lb 2.3 oz
C40: 3.8 oz (3% of grist)
C120: 5 oz (4%)
Roasted barley: 2 oz (1.6%)

I did not acidify the mash. I’ve played around with the calcium and dark grain variables to see if I could create a model condition with a pH ~5.0 (and determine if I made an error in my measurements). Even if I double all of the key variables, the predicted pH is 5.11. So it’s unlikely I made a meaningful measurement error.

I’m using the supporters version 2.12. Out of curiosity I downloaded the current free version and plugged the original variables in. The predicted pH was 5.2.

[kcbeersnob]

[quote=“Silentknyght”]
To the OP: the only thing I can think of is a bad calibration on the pH probe. I’d verify your meter’s calibration/accuracy using clean reference solution.[/quote]
Thanks. As noted above, the pH meter had been calibrated prior to measuring the sample. It’s reading the reference solutions at 6.99 and 4.00. I always use fresh/clean solutions for calibration.

[kcbeersnob]

Just mashed in an all base malt batch (2 row and wheat) using 100% distilled. Target 5.35 pH. Actual pH 5.32. I used slightly less acid than recommend.
It is possible that I forgot to swirl the probe when measuring yesterday. That makes a difference sometimes.

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