Mash pH confusion

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guypettigrew
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Mash pH confusion

Post by guypettigrew » Sat Feb 09, 2019 12:05 pm

Getting the right pH for my mashes seems to be no more than a matter of luck.

Data from the last 4 brews is given below.

Alkalinity reduced using CRS for all brews and measured using a Salifert kit. Alkalinity given as ppm CaCO3. pH measured at 15-20 minutes into the mash using a Voltcraft PH-100ATC. Wort temperature reduced to 20°C for measurement. pH meter calibrated before use with pH 7 and pH 4 buffer solutions.
  • Liquor alkalinity 45, pale malt 74.8%, Vienna malt 18.7%, Crystal malt 4.7%, Chocolate malt 1.9%. pH 5.4
  • Liquor alkalinity 16, pale malt 83.1%, Vienna malt 12.2%, Biscuit malt 4.6%. pH 5.4
  • Liquor alkalinity 30, Pale malt 90.6%, Crystal malt 5%, Chocolate malt 1.3%, Flaked oats 3%. pH 5.2
  • Liquor alkalinity 18, Pale malt 89.6%, pale Crystal malt 6.8%, flaked oats 3.6%. pH 5.6
The first three are within an acceptable range (pH 5.2-5.5), with just one being at the bottom end of the range. Today's brew, the last one, is above the top of the range.

Any thoughts on what's going on would be appreciated, together with ideas on how to get the pH routinely dpwn to the bottom of the acceptable range.

The beers all taste ok, by the way!!

Thanks.

Guy


guypettigrew
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Re: Mash pH confusion

Post by guypettigrew » Sat Feb 09, 2019 2:27 pm

Aleman wrote:
Sat Feb 09, 2019 1:55 pm
Calcium levels ??
102 ppm. Wallybrew analysis. No salts added to the liquor or the grain.

Guy

Saintkel
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Re: Mash pH confusion

Post by Saintkel » Sun Feb 10, 2019 5:00 pm

Have you tested your alkalinity and pH of your mash water after you have treated it? Or just 20 minutes into he mash?

guypettigrew
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Re: Mash pH confusion

Post by guypettigrew » Sun Feb 10, 2019 5:26 pm

Alkalinity as in the first post. This is the value in the HLT after using AMS/CRS. Not bothered with testing the liquor pH as I don't think it matters.

Guy

Saintkel
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Re: Mash pH confusion

Post by Saintkel » Sun Feb 10, 2019 8:07 pm

Ah got you, yes, last one 18ppm alkalinity and it still came in at 5.6 after 20 minutes. Mine was 5.5ph today and that started at 175 ppm and knocked it down to 30 ppm with CRS

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Aleman
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Re: Mash pH confusion

Post by Aleman » Mon Feb 11, 2019 10:46 am

I actually don't think 5.6 is out of an acceptable range ... I normally accept anything within 5.2 to 5.8, which is where pH tends to fall anyway even if you do nothing :D One of the issues here is different 'author'ites quoting different acceptable ranges, and they are getting narrower and lower as time goes on.

What we are trying to do, is to get the pH in the most favourable spot for the various enzymes that are involved in the process, unfortunately these vary wildly so we are not going to please all of them. The proteases and Lipases are happier at the lower end, the amylases are happier at the higher end ... given properly processed malt, it's the amylases that are the most critical aspect oif this so I tend to be happy with 5.4 to 5.7 ... The 5.7 for 'bigger' beers as that is favouring beta amylase

killer
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Re: Mash pH confusion

Post by killer » Mon Feb 11, 2019 11:45 am

I’d be happy with a pH range of 5.2 – 5.6.

As long as your sparge liquor is low enough in alkalinity and has a decent amount of Calcium.
If you are looking for the source of “error” or discrepancy there are a couple… The alkalinity is not an exact figure – It could be plus or minus 10 ppm – given the error in the plastic syringes and when the real end point actually occurs. Then there is the precision of the pH meter – I have the same and the manual says 0.07 units, but I’ve also read 0.2 units elsewhere online. That means that even calibrated, a pH 5.40 mash could be 5.33 or 5.47. Remember precision is not resolution – while the meter boasts 0.01 unit resolution and so can determine the difference between 5.00 and 5.01 it may actually report values of 5.07 and 5.08.

As long as the beer is good I wouldn’t get too hung up on it.

guypettigrew
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Re: Mash pH confusion

Post by guypettigrew » Mon Feb 11, 2019 3:57 pm

Thanks all. Feel much happier now about the pH readings I'm getting. I'd thought 5.2-5.5 was the 'only' range, and the closer to 5.2 the better.

From what you've said, Aleman, my usual readings of 5.4, with variances to 5.2 or 5.6, are absolutely fine. Good to know.

And yes, killer, I think I have been getting a bit OCD about hitting a repeatable figure! Your points about the meter are well made and much appreciated.

Thanks again.

Guy

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