I have no personal experience here but Vito recommends a Kegland pH Meter which is $54.99 at MoreBeer. Cheers!
Do you want accuracy and reliability? If so, I'd recommend Milwaukee MW101 or MW102. I've seen too many examples of the cheap pen-type meters where they just don't work well or for long. Or you could just buy the meter recommended by the vendor that sells it.
MW101 or 102. One thing that often fails to get mentioned when buying a pH meter is maintaining the meter is incredibly important. The probe needs to be stored in the storage solution and they ideally need to be calibrated every time you use them. Also it’s best to not leave the probe in RO water throughout the day while you’re using it. We calibrate our meter every day just to be safe. And don’t forget to replace the probes once/year or every two years depending on use. They’re an invaluable tool but require a bit of maintenance.
Good point. I've asked professional chemists (not home brewers) about calibration and received conflicting advice. Some advocate a three point calibration, others say a two point calibration is sufficient. Also difference in order of calibration, I.e. low - high or high - low. Could you enlighten on what works best for you?
2 point calibration 7.0 -> 4.0 That’s the method that the MW102 dictates. Guess I don’t know any different as that’s all I’ve ever done. Don’t really see a need to calibrate to 10.0 as you’d pretty much never see anything that high. We’re always using RO water so never checking pH of water which is the only thing that would be that far out of the 4->7 range.
If you run out of storage solution the pH 4 buffer will work in a pinch. The most important thing is to limit exposure to low ionic content water (RO or DI). When I worked in environmental labs the EPA procedures called for a calibration every 2 hours - and that is for very expensive benchtop meters. On the other hand I have pulled my cheapo Milwaukee home meters out of 3 month hibernation and found that they retained their last calibration pretty well. Every day you use it is probably the best method. The Milwaukee meters are cheap enough to just replace when they start going bad. But the only time I totally f'd one was when I dropped it on the concrete floor.
Thanks for the details. What I don't see discussed is temp compensation. Some have it, some don't. I've been told to both never use it and conversely to always trust it. If waiting for a wort sample to naturally cool you're talking about a significant time at beginning of mash. What do you find works best in the real world brewhouse?
high temps ruin the probe faster than anything. Always use coolish wort. Cut the top off a 12oz can, put hot wort in 12 oz can. Swirl around in ice bath for 20 seconds and it should be plenty cool.
I think cooling it down to 25C is best. Temperature compensation is only partially effective. There are two parts to pH and temperature. First, high (or low) temperatures will change the response of the probe. I think that this what most temperature compensation corrects for. The second part is that the actual pH changes with temperature. Your mash actually does have a lower pH at 70C than at 25C because the higher temperature means that the activity of the hydrogen ions is higher. This is hard to do a generic correction for because the buffering capacity of different solutions vary so much (and also vary with temperature). The brewing literature is not always clear about temperature when measuring mash pH. My assumption is that measuring the wort at roughly room temperature is the best procedure. And your probe will live longer if you don't expose it to a lot of thermal shocks. That said, close is probably good enough. I got into a mild argument about this with a highly respected (and rightly so) commercial brewer after he stuck his probe right into the mash tun. "But it's temperature compensated". Ballpark is good enough to make some of the best beer in the world.
I use ph meters constantly at work. https://bluelab.com/usa/bluelab-combo-meter I've used the meter for years (it's about 40% cheaper at my local store, maybe $180) and it's incredibly resilient to abuse by untrained and careless users.
As @skivtjerry alluded, pH meter temperature compensation isn't what most people think. I don't know of any meter that compensates for the temperature driven pH change of the solution. I can't even picture a valid formula that would do that. A freezer speeds up the cooling of small wort samples. But I'll just add that by the time the pH of a mash stabilizes enough to give a meaningful measurement (say 15 minutes into the mash), any subsequent pH corrections are of (IMO) limited value. So I recommend measuring pH and learning from it for subsequent batches of the same recipe. Otherwise, trust whatever mash calculator seems to agree with your results the most often.
Exactly. I don't always even measure pH when repeating a recipe. I know what's going to happen. But if I change malts or mess with my water I'll measure a lot.
Amen brother . . . although I'd like to have seen that probe in a mash tun I guess I've adopted this approach by default. For several years I'd faithfully measure a mash sample and it was always PDC to what the software predicted . . . never needed a correction to the mash. Then when my ph meter "died" I lacked the motivation to replace it, just let the software do its thing. This pretty much confirms my suspicion that while pH of the mash is important there's a pretty big window of acceptable results.
The pH of the mash isn’t all that critical. Anywhere between 5.2 and 5.6 will most likely yield the same “resul”t especially at the homebrew level. But what’s much more important is how the pH evolves from there. Final runnings, kettle full, and knock out pH are honestly more important measurements to know and manipulate depending on what your goal is for the beer. Usually a “correct” mash pH will lead to acceptable results from there on out but not always. We take pH and gravity readings 3 times during the mash, as many as four times during the lauter and three times during the boil as well as every day the beer is in the FV with different targets for each measurement and often adjustments with acids or salts along the way.
