Testing Mash pH

[Senior Monkey]

I have a pH meter left over from wine-making days. For this next brew (our 3rd) we want to test the mash pH 20 minutes into the mash. (This is the time I'm seeing in several posts and Mr. Palmer's book.) My noobe question is: Do I just draw off some liquid from the bottom of the mash tun? I know we need to cool it to near room temperature before taking the reading.

 

[balrog]

My suggestion is to stir the mash before sampling or you'll risk sampling stratified mash. You want to sample a homogenous bulk. And yes, cool to room temp, ideally the calibration temp of the meter (you *DO* calibrate first, yes?).

 

[dmtaylor]

Yes, you can drain out of the bottom. Although...

Personally, I dunk the thing straight into the top of the mash at ~150 F, and simply add 0.25 to the hot value to get the room temperature value. This 0.25 is based on experimentation of my own and of many others (Palmer, Strong, Troester, etc.), as well as the fact that I’ve been doing this for a couple of years and the probe is NOT damaged as far as I can tell, despite what all the naysayers will tell you. But I’m only using a $15 probe. If I had a $100 model then admittedly, I might not be quite so bold… maybe.

 

[TheHopfather]

I'm pretty sure I saw AJ and Martin talking about how 30 minutes is the better length of time to wait to sample these days.

I recirculate my mash so everything is all mixed up already. I just dip a shot glass into the wort, put the shot glass in a bowl of ice water to cool it quickly. Make sure you calibrate the meter right before using it. That's about all there is to it.

 

[cire]

Mash pH will change with time. It has been historic practice to report mash pH measured at knock-out, i.e. that of the first runnings at the end of mash. I measure mash pH no earlier than 30 minutes and also take readings when sparging to ensure pH remains low to avoid extraction of undesirables.

Heavy gauge glasses are held in the freezer until a sample is required, when wort in the mash is gently recycled before taking a small sample. It is swirled in the glass until it cools to 20C, is then transferred to a small plastic container at ambient temperature to measure pH.

 

[balrog]

50ml Syringe
Stir mash
Suck up sample in syringe
Set aside

Simple, very alliterative, method.

 

[Senior Monkey]

50ml Syringe
Stir mash
Suck up sample in syringe
Set aside

Simple, very alliterative, method.

Once again, I thank all of you for your quick, helpful, non-judgmental advice. I think we're ready for our next brew.