Contradictory pH results in Brewer's Friend Calculator

(That's water to the rest of us!) Beer is about 95% water, so if you want to discuss water treatment, filtering etc this is the place to do it!
Post Reply
MTW
Drunk as a Skunk
Posts: 895
Joined: Thu Feb 13, 2014 9:04 pm
Location: Just outside Scarbados

Contradictory pH results in Brewer's Friend Calculator

Post by MTW » Sat Mar 02, 2019 4:51 pm

Anyone familiar with the "Brewer's Friend "Mash Chemistry and Brewing Water Calculator" may be able to help with this. [If you've got a saved record on there, maybe even see if it does the same as mine.]

When I enter the grist info by the percentage of predicted beer colour that is calculated to come from the roasted grains, rather than entering each component of the grist more precisely, it yields a very different pH result for the same mash. It predicts 5.4 by roast colour only, and 5.6 with full grist info, for my recent stout. The stout prior to that gets a result of 5.2 by roast colour and 5.4 by full grist info, with the salt additions I had entered. They're quite big differences. I only have maltmiller narrow range pH strips to test with on the day, not a meter, and if I were to believe the test I did (10 mins in, cooled sample), then my recent stout was closer to the colour-only prediction (actually, perhaps lower still than the 5.4 predicted; certainly not the 5.6 predicted by the full grist input).

You'd think that giving BF more information, with the full grist, would yield a more accurate prediction, though that's not backed up by what I may have found. The fact there is such a difference in the two predictions anyway seems odd. I entered the grist as accurately as I could, though I had to count oats as a base malt, due to the limitations of the options on that section. I don't imagine that affects it much. With the roast-colour input, I noted the predicted beer colour in my software, zeroed the roasted grains, and calculated the percentage the roasted grains must have contributed to the colour from the difference.

Anyone use this calculator and tests the actual mash?
Busy in the Summer House Brewery

Silver_Is_Money
Steady Drinker
Posts: 47
Joined: Thu Sep 13, 2018 2:35 pm
Location: N/E Ohio, USA

Re: Contradictory pH results in Brewer's Friend Calculator

Post by Silver_Is_Money » Sun Mar 03, 2019 1:02 am

pH strips are simply not known to be very accurate at all. And particularly more so in media which contributes its own color. That said, I agree with you that the (now relatively aged) Kai Troester (Braukaiser) based color only section of Brewers Friend seems to offer lower mash pH predictions than the more modern grist component method that it employs (and for which I do not know who's math model methods are being utilized). I also agree that the lower pH predictions of Kai's older method seem (based upon my mash pH measurements) to be more accurate. Unless there have been changes to the Brewers Friend website that I'm not aware of, the "color only" mash pH predicting section of Brewers Friend is based directly upon Kai's original calculator known as the "Kaiser Water Calculator", which is still available (or was last time I checked) as a free download on the internet, and which runs within a spreadsheet.

But as the developer of 'Mash Made Easy' I must admit that I'm fully biased toward thinking that my own spreadsheet (particularly its latest version 5.60 release) based mash pH assistant tool is quite accurate in its own right. Mash Made Easy is free and complete, and is available as an internet download.

MTW
Drunk as a Skunk
Posts: 895
Joined: Thu Feb 13, 2014 9:04 pm
Location: Just outside Scarbados

Re: Contradictory pH results in Brewer's Friend Calculator

Post by MTW » Sun Mar 03, 2019 4:26 pm

Very grateful for that info.

I ran the recipe through your MME calculator. It would seem to concur with the lower prediction for my recent stout, ie the one generated by putting the roast colour only into the BF calc. To hit a mash pH of 5.4 with the salts I added, MME generates a requirement of 0.52g baking soda; I added 1g, which I assume is near enough to be within tolerance limits. [If I increase the alkalinity of the source water by 10ppm, it switches to requiring a touch of acid, so it must be very close.]

The higher prediction (from entering full grist into BF] certainly didn't seem right to me; it required me to add enough acid to reach a level of CACO3 that I would consider normal for a far paler beer, for a 5.4 mash.
Busy in the Summer House Brewery

Post Reply