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kerklein2

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I'm in the market for a good pH meter and have been searching around. Found what appears to be an awesome choice from Omega today and wanted to post it and get some thoughts on it. It appears it could be the best model around for brewing, when price is considered.

Here are the specs:


And it's $95, comes with a plastic carrying case, as well as calibration solutions, a lanyard, and batteries. It'as also IP67 waterproof.

Is this a great find or am I missing something?

http://www.omega.com/ppt/pptsc.asp?ref=PHH-7000&Nav=grebb02
 

brewmaster101

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following your post let me know how it turns out I'm interested in this as well
 

DSmith

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Specs look good for 0.01 pH resolution/accuracy.

The link to the Hanna pHep5 below is a popular pH meter at about the same cost. I own this one and do not regret the purchase and have no experience with the Omega one. The Hanna doesn't come with a lot of solution so you'd need storage, cleaning, 4.01 buffer & 7.01 buffer solutions. I'd budget an extra $50 no matter what brand you choose to get the solutions.

http://www.eseasongear.com/hahi98waphtt.html

http://www.hannainst.com/usa/prods2.cfm?id=040003&ProdCode=HI 98128
 
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kerklein2

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The reason I think this one is superior to the Hanna is the temperature range. Hanna can only auto-temp correct up to 140F which is below the range of all mashes. This one goes up to 176F which covers all mash temps and even a sparge. Gives you a lot more flexibility to measure pH right in your mash tun without cooling a sample.

Not to mention it's more accurate. And it comes with a carrying case. The IP67 rating is also reassuring over just "waterproof".
 

DSmith

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A lot of the mash pH guidelines now are based on room temperature measurements, not that you can't adjust for that. I just think you unnecessarily risk damaging your pH meter probe at mash temperature. I store some ceramic mini cups I bought at a thrift shop in the freezer to collect a sample - it's cooled to 80F before the meter is calibrated. I calibrate the pH meter before every reading.

The accurace specs aren't significantly different. Accuracy better than 0.1 pH is the goal. The Omega meter does look nice, just wanted to point out the Hanna option too.
 
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kerklein2

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I guess I don't understand how you are risking damaging the probe if it's rated to beyond mash temps? And the accuracy is 5X better, which I know isn't that important for us, but it's always good to get better accuracy for the same money right?
 

DSmith

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I can’t say anything to discount the temperature rating of the probe.

The pH meter is ideally isoelectric at pH 7 (pHi). ATC works best around pHi and your mash pH is not 7. The most accurate measurements will be made at temperature consistent with your calibration solutions and the ATC error will be insignificant.
 
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kerklein2

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So reading a little more, it sounds like the main issue is true pH drift over temperature and that most mash pH guidelines are given at room temp. Given that piece of information, it seems like directly measuring mash temps isn't a great idea as the pH change with temperature doesn't appear to be mathematically predictable. It would be handy if there was a trusted source that discussed pH change at temperature and reported suggested values at mash temp. I guess you run in to the ATC errors you mention above though.

I still think it looks like a great meter as it's the same price as the Hanna but has an improved feature set. And the case is nice.
 

DSmith

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So reading a little more, it sounds like the main issue is true pH drift over temperature and that most mash pH guidelines are given at room temp. Given that piece of information, it seems like directly measuring mash temps isn't a great idea as the pH change with temperature doesn't appear to be mathematically predictable. It would be handy if there was a trusted source that discussed pH change at temperature and reported suggested values at mash temp. I guess you run in to the ATC errors you mention above though.

I still think it looks like a great meter as it's the same price as the Hanna but has an improved feature set. And the case is nice.
Exactly.

pH meter accuracy is related to the calibration solution (0.01 pH typically for fresh solution - never reuse solution after a brewing day, rinse the pH meter with distilled water to prevent cross contamination). So as long as you have 2 decimal place resolution they are going to be about the same. The inexpensive meters drift out of calibration with time so the work-around is to calibrate often.

The case is nice, but, pH meters should be stored upright with the tip submerged in storage solution. The Omega one has a "soaking cap" with soaking solution - probably would keep the solution in the cap longer standing up.
 
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