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General Category => Equipment and Software => Topic started by: denny on February 15, 2010, 08:11:52 PM

Title: pH meter questions
Post by: denny on February 15, 2010, 08:11:52 PM
Due to the generosity of my wife and BIL, I've got bucks to burn at the LHBS (well, gift certificates, anyway).  I'm totally stocked up on brewing supplies, so I think I'm gonna pick up a pH meter.  The one he sells is the Milwaukee pH51.  Anybody have any experience with this brand?  And any tips you can give me for using it?  I assume I'll want to pull a sample and cool it down as opposed to just sticking the meter in the mash?
Title: Re: pH meter questions
Post by: Kaiser on February 15, 2010, 09:05:33 PM
This seems to be the Milwaukee equivalent to the Hanna pHep meters we discussed here: http://www.homebrewersassociation.org/forum/index.php?topic=1266.0

Kai
Title: Re: pH meter questions
Post by: denny on February 15, 2010, 09:09:37 PM
Thanks, Kai.  I just noticed that thread and posted some questions there.
Title: Re: pH meter questions
Post by: toastedman on February 16, 2010, 04:36:52 AM
    i just saw the milwaukee ph51 on e-bay for 49.50, the better one is the ph56 it has accuracy of + - 0.01 and auto temp for 64.95 + ship 5.99
Title: Re: pH meter questions
Post by: denny on February 16, 2010, 05:06:54 PM
Thanks....I know I can get it a lot cheaper on the internet, but I've got beaucoup gift certificates for the LHBS.  I'm just gonna get what he's got.
Title: Re: pH meter questions
Post by: tfries on February 17, 2010, 09:07:04 PM
Hey Denny,

I have a Milwaukee ph meter, different model number though.  You are right that you do not want to just stick the meter into the hot mash.  Pull out a sample and let it cool down.

You will also want to buy bottles of the calibration solution and storage solution.

Title: Re: pH meter questions
Post by: pjj2ba on February 18, 2010, 05:32:34 AM
Also, get yourself a squirt bottle.  I finally got a home pH meter and thought for a minute that, hey I need something to rinse off the electrode.  I often use one at work and it is just second nature that the squirt bottle is always there for electrode rinsing.  I got mine conveniently on campus and filled it with RO water from the lab.  A squirt bottle (ketchup, mustard, etc. ) from a cooking/restaurant supply store would be a good substitute
Title: Re: pH meter questions
Post by: euge on February 18, 2010, 07:07:02 AM
That's a good idea with the bottle. I rinse mine in the sink and use an old soft toothbrush to gently clean the electrode. I also auto-calibrate once it shows a variance of 0.10 pH in clean storage solution. Gets used all the time, so when I have to calibrate it too often then a cleaning is certainly needed.

Title: Re: pH meter questions
Post by: Kaiser on February 18, 2010, 02:18:53 PM
I just fill a cup with R/O water from the tap to rinse the electrode before and after testing a sample.

Kai
Title: Re: pH meter questions
Post by: denny on February 18, 2010, 05:08:08 PM
Hey Denny,

I have a Milwaukee ph meter, different model number though.  You are right that you do not want to just stick the meter into the hot mash.  Pull out a sample and let it cool down.

You will also want to buy bottles of the calibration solution and storage solution.



Thanks, Tom.  I got the calibration and storage solutions when I bought the mer from Jim.
Title: Re: pH meter questions
Post by: bluesman on February 18, 2010, 05:39:12 PM
All this talk about pH meters has me adding it to my wish list. Nothing like good QA during the brewing process to assure better beer.
Title: Re: pH meter questions
Post by: euge on November 19, 2010, 07:10:26 AM
I've dusted off my pH meter. Has been in storage solution for the last 7 or so months. A couple weeks ago I pulled it out to check and a bunch of slime was growing in the cap. I cleaned and tested the meter with new 7.0 solution. Read 7.4 so it got calibrated. Fine. Just checked it again and more slime. Read 7.8 but I briefly soak the cap and probe in everclear and recalibrate.

Tested it against a known solution and it is accurate.

What is this slime? I don't see anything in the bottle of storage solution which looks as clean as the day I bought it.
Title: Re: pH meter questions
Post by: jaybeerman on November 19, 2010, 05:51:41 PM
Denny, I used a Milwaukee ph51 nearly every day for about 6 months, a while back.  Its build is good and it's accurate enough for most brewers.  I actually know two brewpubs that use that exact ph meter (and always Milwaukee meters).  I recently upgraded to a Milwaukee SM101 and I've been impressed with this meter as well.  Enjoy
Title: Re: pH meter questions
Post by: denny on November 19, 2010, 06:11:28 PM
Jay, thanks so much for the personal data point.  I've been really happy with mine so far.  Like you say, the resolution is plenty good enough for my uses.
Title: Re: pH meter questions
Post by: euge on November 19, 2010, 06:17:56 PM
What? No one have any ideas about the slime?
Title: Re: pH meter questions
Post by: denny on November 19, 2010, 06:40:36 PM
What? No one have any ideas about the slime?

Wasn't that a bad horror movie?  ;)
Title: Re: pH meter questions
Post by: euge on November 19, 2010, 06:43:57 PM
LOL.

I'm a bit concerned though. I don't like slime.
Title: Re: pH meter questions
Post by: denny on November 19, 2010, 07:03:45 PM
What about an Oxiclean/PBW soak for the cap?  Then some StarSan?  Don't know how it would effect the probe if you tried it on that, though.  It might work.
Title: Re: pH meter questions
Post by: euge on November 19, 2010, 07:07:55 PM
That's a pretty good idea. I'm thinking the little "wick" part of the probe might have a contamination of some sort.

Won't be sticking it in my fermenters or anything like that LOL. Never would any way but it's always something isn't it...

Makes life interesting. :P
Title: Re: pH meter questions
Post by: mabrungard on November 19, 2010, 09:13:16 PM
From all the indications on pH meter care, it appears that pH meter probes should be kept wet with a potassium chloride solution.  Apparently, Hanna's pH probe storage solution is KCl.  Hanna is one of the major inexpensive meter producers. 

You can purchase the probe storage solution commercially.  You can also make up your own solution by disolving about 22 grams of KCl in 100 ml of distilled water (I'd say that RO water is close enough to DI water). 

By the way, all pH probe manufacturers state that pH probes should not be stored in plain DI or RO water since you'll leach the ions out of the probe and kill it.  Got to have the KCl in there.

For probe cleaning, I use a strong lye (NaOH) solution to remove base soluble deposits.  I use the Red Devil drain cleaner for my lye.  Just remember its not food grade and you'll want to make sure its rinsed off well. 

Unfortunately, I don't have any strong acids at home such as nitric or hydrochloric, but a dip in either of those would help remove acid soluble deposits.  I suppose that high percentage phoshoric acid could be used, but all I have now is 88% lactic and its not a strong acid.  I suppose its better than nothing. The strong base and strong acid washes are typical cleaning regimens for the probes.
Title: Re: pH meter questions
Post by: denny on November 19, 2010, 09:42:15 PM
I suppose that high percentage phoshoric acid could be used

I wonder if undiluted StarSan might work.
Title: Re: pH meter questions
Post by: BrewArk on November 19, 2010, 09:55:44 PM
<snip>
Unfortunately, I don't have any strong acids at home such as nitric or hydrochloric, but a dip in either of those would help remove acid soluble deposits. 

Muriatic acid is available @pool supply outlets and many hardware stores.  It is just another name for hydrochloric.
Title: Re: pH meter questions
Post by: bluesman on November 19, 2010, 10:20:54 PM
I suppose that high percentage phoshoric acid could be used

I wonder if undiluted StarSan might work.

Denny,

Have you tried contacting the manufacturer?

They should be able to answer this question. Maybe they can also give some other options for probe storage.

Just a thought.
Title: Re: pH meter questions
Post by: denny on November 19, 2010, 10:56:09 PM
I suppose that high percentage phoshoric acid could be used

I wonder if undiluted StarSan might work.

Denny,

Have you tried contacting the manufacturer?

They should be able to answer this question. Maybe they can also give some other options for probe storage.

Just a thought.

I'm not having any problems (knock on wood!) with using storage solution.  My comment was in response to Martin mention phosphoric acid.
Title: Re: pH meter questions
Post by: James Lorden on November 26, 2010, 08:55:18 PM
I have had is meter for a long time.  I know the electrode needs to be replaced occasionally but mine seems to still work fine (over a year old).  What is the best indicator that a replacement is needed?
Title: Re: pH meter questions
Post by: punatic on November 26, 2010, 09:43:17 PM
Cleaning your pH probe with a strong acid or base or any kind of harsh cleaning solutions is a bad idea! 

What causes pH probes to slow down and fail is the buildup of scale on the bulb.

Mix up a dilute citric acid solution and soak the probe overnight in that.  Use 1/2 tsp of citric acid crystals dissolved in 50mL of DI water.  Citric acid crystals are available at your LHBS.

When I notice a pH probe taking longer than usual to settle on a value I will store the probe in a 4 pH buffer overnight.  If that doesn't work I will do a citric acid soak.

Also, do not "scrub" the bulb on your pH probe with anything even slightly abrasive.  Use a fine water jet, like the one delivered by a squeeze bottle, to do the mechanical cleaning of the bulb.  Then pat the bulb dry with a soft cloth or soft paper towel.

If your pH meter/probe has a cap to cover the probe end with, keep the cap filled with KCl probe storage solution.  If you store you probe in a beaker or flask you may prefer to store it in a 7 pH buffer solution.  A 7 pH buffer solution is almost as good as a KCl solution for storage.  If you use a KCl solution in an open container you will find the liquid evaporates and makes a big crystaline mess.

It is VERY important not to let your pH probe dry out. If you have no storage solution keep it wet with plain water.

I use a Hach HQ40d pH/Conductivity/LDO portable meter (http://www.hach.com/hc/search.product.configurator/PackagingCode=HQ40D_CONFIGURATOR/NewLinkLabel=HQ40d+Dual-Input+Multi-parameter+Meter%20Configurator/SESSIONID%7CB3lPVEE0TURZMk1qYzVOekVtWjNWbGMzUkJXQT09QWtkWFJURQ==%7C)

But I use it for more than just my hobbies.