Different pH estimates with different calculators

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Matt in Birdham
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Different pH estimates with different calculators

Post by Matt in Birdham » Wed Sep 28, 2016 8:54 am

For a while now I have been using the EZ Water spreadsheet to calculate mineral and acid additions. I have noticed that the predicted result is *always* 0.1-0.2 pH above that which I actually measure in the mash (two-point calibrated pH meter, room temp, 10 mins into mash). Annoying, but I kind of got used to it and always aimed a little higher, with extra acid malt on hand to bring it down if required.

After missing yet again during yesterday's brew, I decided to try a few other calculators and see what results they gave. Quite different, as it happens..

For this brew I started with 100% RO water, which I entered as zero for everything (not quite true, I know). I then added salts to arrive at the following:

Ca ppm: 96, Mg ppm: 5, Na ppm: 23, Cl ppm:63, SO4 ppm: 220

Grist was 3kg pilsner, 2kg Golden Promise and 0.25kg Caramalt in 34 litre (full volume) mash. All salts added to mash water.
100g acidulated malt was also added, with more on hand if required (it wasn't).

pH predictions without acid malt and with 100 acid malt (in brackets):

EZ Water: 5.56 (5.48)
Brewers Friend: 5.43 (5.25)
Kaiser Water: 5.45 (5.31)

Measured: 5.2

It seems clear to me now that it is time to deep six the EZ water spreadsheet, as the results (for me) seem to be consistently wrong, but I am curious to know what other peoples' experiences are with this (and other) calculators and which gives the best results for you. The Brewers Friend one seems easy to use and simple enough, and the prediction for this brew was the best, so perhaps I'll stick with that for a while. I do find the range of predictions concerning though..

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Re: Different pH estimates with different calculators

Post by Jocky » Wed Sep 28, 2016 9:12 am

They're all estimates, so useful as a starting point if you have no idea, but beyond they're no replacement for proper process -measure, take notes and adjust what you do in future brews if the pH is off.
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Matt in Birdham
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Re: Different pH estimates with different calculators

Post by Matt in Birdham » Wed Sep 28, 2016 9:30 am

Jocky wrote:They're all estimates, so useful as a starting point if you have no idea, but beyond they're no replacement for proper process -measure, take notes and adjust what you do in future brews if the pH is off.
Yeah - certainly, I get that and I do measure and adjust. It just got to the point where I found the estimate was always off, and always over what I measured, so I was interested to see that a couple of other calculators out there seem to be more accurate - for this particular beer, at least. A full 2/10 of a pH point is quite a big difference though, for what is a fairly simple grist so I also wonder if there are calculators out there that people tend to find more accurate than others.

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Aleman
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Re: Different pH estimates with different calculators

Post by Aleman » Wed Sep 28, 2016 9:37 am

The predictions are just that predictions . . . I could be less charitable and call it complete guesswork, but that often offends :D. It's based on a small piece of work by Kohlbach that used very range of conditions, and the developers of these guestimators have extrapolated these results to apply to a completely different range of conditions.

Anywhere between 5.2 and 5.8 will produce acceptable or even damn good and as long as the alkalinity is right and you have sufficient calcium the pH will fall into that range, I've long since realised that there is very little point in worrying obsessively about it. with time and experience I have developed water treatments suitable to the grists and mineral levels I find appropriate for the styles I brew, and the pH falls where I expect it every time. I've been caught out recently with the change to FV mashing, but have made a few changes to the water treatment and I'm now bang on the money again.

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Re: Different pH estimates with different calculators

Post by BenB » Wed Sep 28, 2016 11:13 am

I find Brunwater gives me an eventual mash pH .2-.3 above estimated so I just aim lower on the calculated pH. Again two point calibrated pH meter.... measured at room temperature etc. Still not 100% sure about target pHs for different brews so doesn't matter too much! ph 5.2 for light beers and up to 5.4 for dark?

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Aleman
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Re: Different pH estimates with different calculators

Post by Aleman » Wed Sep 28, 2016 12:23 pm

BenB wrote:ph 5.2 for light beers and up to 5.4 for dark?
More like 5.3 to 5.5 for pales and 5.5 to 5.8 for Darks . . . if you want to be completely obsessive about it

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Re: Different pH estimates with different calculators

Post by Matt in Birdham » Wed Sep 28, 2016 12:54 pm

Aleman wrote:
BenB wrote:ph 5.2 for light beers and up to 5.4 for dark?
More like 5.3 to 5.5 for pales and 5.5 to 5.8 for Darks . . . if you want to be completely obsessive about it
I was reading a forum post the other day (somewhere else), where a poster claimed that Sierra Nevada targeted 5.2 (room temp) for its pale ale. I believe the brewery had confirmed it with him, and he also observed them taking a pH measurement during a brewery tour - so I think I believe it. Interesting, as it is indeed somewhat lower than the standard, current wisdom, but I would rate SN as a technically excellent brewery, and I plan on trying this myself (indeed, yesterday's brew was 5.2 or thereabouts, although not by design, so I guess I already have tried it..).

I once made a pale with a 5.0 mash pH (a cock up). For reasons unknown, I decided not to try and modify the pH and let it run. This didn't turn into a particularly good beer, but I don't know how much of this (if any) was due to the mash pH. One thing I do remember is that my cold break didn't floculate at all, despite the usual kettle finings - it remained as a fine suspension after chilling (IC), but the final beer clarity was not impacted.

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Re: Different pH estimates with different calculators

Post by Aleman » Wed Sep 28, 2016 1:26 pm

I'm not saying that pH 5.2 is bad, as it isn't that simple, it's just not that critical. Again it comes of looking at a experiment where you hold all the conditions you can constant and try and vary one, and then drawing conclusions from that result that you apply to the mash, where everything is changing all the time.

I've brewed a Russian Imperial stout with a mash pH of 4.85(*), and it's still a damn good beer and getting better with age ;)

Had no issues with the break, indeed the break occurs as the mash pH falls through the boil, so a lower starting pH should get an earlier break.

(*) It was one of those times when you look at the foil packet of treatment salts left with the remaining hops half way through the boil, and go "What's in there?"

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Re: Different pH estimates with different calculators

Post by simple one » Wed Sep 28, 2016 3:40 pm

What is the ideal pH for the break? Or is it the range of the fall which encourages it?
Hard to find the time.... But getting the occasional one in now and again.

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Re: Different pH estimates with different calculators

Post by Matt in Birdham » Wed Sep 28, 2016 3:44 pm

This page is a very good read on the effect of pH on brewing.

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Re: Different pH estimates with different calculators

Post by Aleman » Wed Sep 28, 2016 3:53 pm

Yep a very good explanation.

The issue is that a lot of the enzyme reaction experiments are using a purified extract of the enzyme, in a 'standard' substrate, held in a water bath at a constant temperature . . . and then you plot the rate, probably of production of product, vs pH . . . and note there is no scale quoted on the vertical axis ;). then you come to a conclusion that for those conditions pH has an effect (*). . . . Not that I was talking generally rather than that particular web page. The thing I took from that was that mash pH in the range 5.3 to 5.7 will produce acceptable beer. . . .Dropping to pH5.2 has significant benefits in a commercial environment, that does not necessarily apply at our volumes





(*) Directly comparable to a mash . . . I think not . . There are other factors that have a much more significant effect on rates of reactions within a mash other than pH

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simple one
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Re: Different pH estimates with different calculators

Post by simple one » Wed Sep 28, 2016 4:01 pm

Cheers. Interesting reading.
Hard to find the time.... But getting the occasional one in now and again.

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