Monitoring mash Ph

[maplemontbrew]

Will be using a Hanna ph meter with temperature compensation to monitor my mash ph, however I have a couple of questions about the procedure for doing this. First, I have seen some posts that say the sample needs to be measured at room temp despite the use of a temp compensating meter. Second, when during the mash do I take the reading - beginning, middle, end or all three?

 

[ajdelange]

Will be using a Hanna ph meter with temperature compensation to monitor my mash ph, however I have a couple of questions about the procedure for doing this. First, I have seen some posts that say the sample needs to be measured at room temp despite the use of a temp compensating meter.

That's correct. See https://www.homebrewtalk.com/f128/ph-meter-calibration-302256/

Second, when during the mash do I take the reading - beginning, middle, end or all three?

Yes, by which I mean take lots of readings and that includes kettle wort, before and after the boil (all cooled to room temp), wort in the fermenter, finished beer etc. until you see what is going on and thereafter as often as you find pH checking is useful to you.

 

[maplemontbrew]

That's correct. See https://www.homebrewtalk.com/f128/ph-meter-calibration-302256/ Yes, by which I mean take lots of readings and that includes kettle wort, before and after the boil (all cooled to room temp), wort in the fermenter, finished beer etc. until you see what is going on and thereafter as often as you find pH checking is useful to you.

Great info. Thanks!!!

 

[maplemontbrew]

That's correct. See https://www.homebrewtalk.com/f128/ph-meter-calibration-302256/ Yes, by which I mean take lots of readings and that includes kettle wort, before and after the boil (all cooled to room temp), wort in the fermenter, finished beer etc. until you see what is going on and thereafter as often as you find pH checking is useful to you.

One follow up. I understand that I need to monitor the Ph and gravity of the end runnings of my mash into the boil kettle. Do I need to take a sample from the wort in the kettle or from the hose between the mash tun and kettle? At what point do the readings tell me to stop sparging?

 

[ajdelange]

You would take it from the hose. The general rule is to stop collecting wort when the runoff pH starts to approach or exceed 6. If your water is of models alkalinity you will generally find that you don't get to 6 until runoff gravity is 4 °P or less and that's fine. If your water is highly alkaline then 6 can be reached at higher gravity. You can insure, in either case, that 6 will never be reached by acidifying your water to a pH slightly below 6. Use the pH meter to do that.

 

[maplemontbrew]

You would take it from the hose. The general rule is to stop collecting wort when the runoff pH starts to approach or exceed 6. If your water is of models alkalinity you will generally find that you don't get to 6 until runoff gravity is 4 °P or less and that's fine. If your water is highly alkaline then 6 can be reached at higher gravity. You can insure, in either case, that 6 will never be reached by acidifying your water to a pH slightly below 6. Use the pH meter to do that.

Does 4 °P mean 4 brix?

 

[ajdelange]

Yes, about 1.016 SG. Expressing things in °P was habitual and not to be interpreted as a recommendation that a refractometer be used though this is one of the few places where refractometers work well in brewing.

 

[ianw58]

Brix and Plato are roughly equivalent in the ranges used by brewers.

4°P is about 1.015 SG

 

[mabrungard]

+1 on stopping runoff at an elevated Brix or Plato reading. I suffered a few slightly tannic brews because I allowed the final runnings to fall to 2 Plato. Of course, my sparging water was RO and had very low alkalinity. But that apparently means little. Oversparging will elicit the tannins. AJ's recommendation of 4 Plato should be quite safe. I've been stopping at 3 Plato and have not had the tannin monster rear its head any more. I'll have to bump that up to 4 and see if there is a significant difference in results.

 

[maplemontbrew]

Ok. Tks!

 

[TrickyDick]

Anyone have any clever ways to cool off the wort specimens rapidly?

TD

 

[mabrungard]

I use a chilled shot glass from the freezer that holds about 10 to 15 ml of wort. It chills the sample fairly quickly. This option only works for probes with regular diameter. The integrated probe/meter units typically have larger diameter and may require a larger container and larger sample volume.

 

[slarkin712]

I use multiple freezer-chilled coffee mugs. Pour between the 2 mugs and the sample is cool in 10-20 seconds.

 

[maplemontbrew]

Excellent suggestions!

 

[SpeedYellow]

I keep a small bowl of ice water on the counter, then put the sample in a shot glass and set it in the ice water bath. I used to set the samples in the freezer, but found it took about 6 minutes to cool them.

 

[RoadKing]

To cool a sample I use the bottom of a small Stainless cocktail shaker and put it into a measuring cup full of ice and swirl it around.
The stainless transfers the heat like crazy. I can take a sample from boiling to 70 in under a minute.

 

[mchrispen]

I have taken to two small stainless bowls, nested - the bottom with ice. I put the sample into the upper bowl and give it a swirl, then decant into a shot glass for the reading.

Hasn't been mentioned yet, but even with ATC features, I would note and log the sample's temperature.