I use Bru’n Water to predict my mash pH, in conjunction with actually taking pH readings using ColorpHast strips. As long as I use +.3 pH correction with the strips, they support Bru’n Water’s predicted mash pH 90+% of the time.
Today, I took a pH sample from my IPA mash and the strips indicated a pH of 5.6-5.7 (I almost always shoot for 5.3-5.4). I was sort of skeptical of this reading, so I tried a second strip. It ended up reading the same thing. Out of curiosity, I took a sample of the first runnings and it was dead on at 5.4. With my limited tech/science knowledge, I can’t explain the discrepancy here. Can someone explain why the sample from the mash might have been higher than the that of the first runnings? Which one should I trust as an indicator of mash pH? At this point, I’m more inclined to trust the pH of the runnings sample since it supports Bru’n Water’s mash pH prediction. But maybe the pH of the first runnings should be less than the mash pH? ???
edit: One more thing – I brewed almost this same IPA recipe a few months ago with 1% acid malt. The mash pH was dead on at 5.4. The only things I changed for today’s beer was using a slightly darker English cara malt (approximately 17L darker), and 4% aromatic. According to Bru’n Water, those changes resulted in a .1 pH drop, so I didn’t use any acid malt this time (I use the acid malt ROT that each 1% drops pH by .1).
edit 2: Edited post to clarify that I’m referring to mash pH.
Depending on the particular mash and water combination, the pH can change over the course of the mash. They’re both probably right, it probably just took longer for the pH to equalize due to the dark malts than it did with the lactic acid on the acidulated malt. It sounds like you’re in the right range, though.
If you are interested in getting accurate readings down to the tenth as I am, then I recommend buying a pH meter with resolution in that range. I have a Milwaukee MW101 that can be calibrated and is fairly accurate down to the +/- 0.1 range. You will be able to count on your readings whereas pH strips can be a little subjective in their results.
That meter has been on my wish list for a while. But I just bought a thermapen and I need to wait a little while before I make another gadget purchase.
How are you guys taking mash pH samples anyway? I just take a tablespoon of wort off the top of the grainbed at the end of the mash. Is there a better method?
I think I spent $60-70 on my bench meter. well worth the investments. Those colorpHast strips are trash IMO. I keep some “just in case” something goes wrong with my meter but the color never looks the same as the color key and I just hate 'em.
edit: I just looked at those thermapens. Personally I think your money would have been better spent on a pH meter.
I’ve found that the Colorphast strips read within around .1 of my MW101 (after applying the +.3 correction factor).
When I use the strips, I just dip them in the mash for a few seconds. When I use my meter, I dip a small tasting glass in the mash and stick it in the freezer for a few minutes until it comes down to an acceptable temperature.
I dip a tall shot glass into the mash, trying to pull a sample with mostly liquid to the extent possible. Then I chill it down in a 1 qt pyrex measuring cup filled with ice and water. Just a minute or two of swirling the glass in the ice bath brings the temp right down. I’m using an MW101.
My $7 lab thermometer is quick enough and 100% accurate - I use it to calibrtate all my installed dial thermometers regularly. I check ph all the time and I am surprised at how often it doesn’t check out. YMMV. IN fact I brewed a side batch recently and checked the pH and noticed it was only off a little and the beer never did have a good hot break and the final batch ended up tasting alright but had a stubborn haze. I guess the mash temp checked out at least.
well, I have two of them and if they are both off they are both off the same. I don’t have any issues with FG so I feel confident they are fine. I calibrate often, probably not as often as I should. Regardless, I’d rather be off a couple of degrees than have my pH reading off. I give myself a 2 degree leeway on temp anyway just for sanity’s sake.
I certainly don’t think pH is less important than temperature. They are both obviously important.
I think temperature and pH accuracy are equally important for different reasons. They can both create problems with your beer if they are far enough out of range. Calibration of both measuring devices is important for that reason. NIST traceable standards are the best way to go when calibrating your meter or thermometer. I use pH buffer solutions to calibrate my meter.
anyways this is what happens which i check mash pH… I’m just copying in notes from an Altbier batch about 2 wks ago: “calibrated meter to 7.01 and then 4.01 buffers. read pH of 5.46 @ 24.7C. then put meter in 4.01 buffer. it reads 3.79. now checked 7.01 buffer, it reads 7.03. now back into mash sample, it reads 5.63 at 21.6C.” (my brew room is about 55F this time of year so the sample keeps cooling as I’m checking it)
and from 1 month ago, a Boh Pils: “calibrated meter to 7.01 and then 4.01 buffers. read pH of 5.27 @ 28.9C. then put meter in 4.01 buffer. it reads 3.73. now checked 7.01 buffer, it reads 6.89. now back into mash sample, it reads 5.34 at 20.7C.”
now maybe this is all within the margin of error for this meter and probe, and it’s all “good enough” and I should RDWHAHB etc etc… although I am one who likes to know that what I am getting is really what’s there… or what are you other guys with Milwaukee meters seeing? I use the Hanna storage solution, and the Hanna 4.01 and 7.01 buffer packs from Amazon (I once called Milwaukee and they said it is OK to use Hanna products on their meters)
finally, if mash pH does change during the mash, when do you check it??? I asked this a bout a year ago on this forum, and it seems like most people take it about 5 or 10 minutes after dough-in? of course it takes 10-15 minutes for the sample to cool (I try to consistently read pH around 20-25C [68-77F] even though I have ATC). what are you guys doing about this?
They last about 18-24mos if kept clean and wet in the proper storage solution.
Anyway, I check the mash pH about 10 min into the mash and the sparge after stirring for 2 min. I always calirate with 4.01 and 7.0 prior to the mash and the sparge. I typically get readings within +/-.02 upon calibration, so you either have a failing probe or stray voltage in your system. I recommend contacting Milwaukee and talking to their tech support folks.
One other thing to consider is your sampling temp. I always chill the mash sample down to RT prior to taking a reading.
