When and how should mash pH be measured?

[guypettigrew]

Should it be measured once the mash temperature has stabilised, part way through the mash or at the end?

And should my pH meter be waggled about in the mash or should some wort be run off, cooled to 20C, then measured?

Thanks.

Guy

[Kev888]

Normal practice is about 10min-15mins from mashing in. The wort (edit: a sample removed from the mash) should be cooled to about 20c - partly because room temperature is the standard assumption, partly because most meter's automatic temperature compensation (if they have one) isn't very reliable, and partly because its kinder on the probe.

The same wort at different temperatures gives a different reading, so automated processes that measure warm wort 'live' can't be directly compared with traditional room-temperature readings. I believe lack of distinction over this in some literature may be one reason for disagreements as to the ideal PH range.

[guypettigrew]

Thanks Kev

So, does this mean I should run some wort out of the tun and cool it?

Guy

[Dennis King]

Like Kev I go for 10-15 mins into mash. Poor of a small amount and crash cool, very quick as it's a small sample.

[john luc]

Once I have the mash settled I take a sample of wort in an eggcup and cool it down to 20C then put my PH meter into it and leave it rest for a few minutes. I good practice is to also measure the PH of your last sparge runnings and not let it go above 6.0 PH.

[sonicated]

What kind of meter do you use? Does it need to be calibrated regularly?

[john luc]

I use a pen type. I also do recalibrate regularly

[orlando]

Once I have the mash settled I take a sample of wort in an eggcup and cool it down to 20C then put my PH meter into it and leave it rest for a few minutes. I good practice is to also measure the PH of your last sparge runnings and not let it go above 6.0 PH.

This. After 10 minutes cooled to 20-25c (because this is how the original measurements were taken and is now the standard reporting method, and the benefits Kev mentioned) and always after calibrating as mine drifts. If you treat your sparge water to an alkalinity of 20-25 your last runnings shouldn't be over pH 6 or something has gone badly wrong.

[guypettigrew]

Many thanks everyone.

I've had a pen type pH meter for ages but never known the best way of using it.

It's brewday tomorrow, hopefully, so I'll calibrate the pH meter before getting the mash going (I've got two buffer solutions) then take a series of measurements as suggested.

Guy

[orlando]

Many thanks everyone.

I've had a pen type pH meter for ages but never known the best way of using it.

It's brewday tomorrow, hopefully, so I'll calibrate the pH meter before getting the mash going (I've got two buffer solutions) then take a series of measurements as suggested.

Guy

If you get the mash pH in the right range and your sparge water alkalinity right for the style, what you should see is a gradual fall in pH right through to packaging.

[Kev888]

Would I be correct in thinking that the initial change in mash PH is relatively slow - enough that the varying time taken for different brewers to mash in (i.e. get all the grain warm, wet and contributing) won't cause a significant difference in the initial mash PH measurement?

[john luc]

I find that the PH meter reads the sample but can often adjust 0.1 or 0.2 over approx 10 minutes or so. Not always but sometimes. For me it is built in to my standard brew day as normal as crushing the grain.

[Kev888]

Excellent, thanks - thats more or less as I recalled. So when comparing with others (or preferred PH ranges), slight differences in mash-in rate or sample time aren't going to cause big discrepancies. Though yes, still worth being consistent within one's own process.

[orlando]

Excellent, thanks - thats more or less as I recalled. So when comparing with others (or preferred PH ranges), slight differences in mash-in rate or sample time aren't going to cause big discrepancies. Though yes, still worth being consistent within one's own process.

As I said, do your normal mash in, shut down the hatches and wait 10-15 minutes. I take this time to calibrate the meter, then get the sample and cool to circa 20c, Aleman puts a shot glass in the freezer puts the sample in that and it is almost instantly ready to be read. Leave dunked in for 5 minutes to allow the reading to settle. My next reading is the last runnings, just want to know the pH is below 6. Final brew day reading is of the finished wort, again looking for a further lowering of the pH hoping to get 5-5.2. Final pH in the finished beer should be under 4.4, better still under 4 but the yeast choice plays a significant part here. A pH meter gives you an insight to how your process is doing and can be a guide as to what change in your practices/choices might be required. If you get the mash pH right and reduce alkalinity in your sparge to the correct levels most of this should look after itself. Just nice to know.

[guypettigrew]

Thanks for all the tips. Brewing today and so far the readings have been; 15 minutes into the mash, pH 5.3; end of mash, before beginning the sparge, pH 5.2; final runnings at the end of the sparge, pH 5.6.

I'll take another reading of the finished wort--I'd wondered if that would be worthwhile. I'll also go and check the pH of the beers I've got on tap. The thought of checking the beer pH hadn't even crossed my mind!

Guy