Author Topic: pH Meters - Important Info!  (Read 4518 times)

Offline chilipepper

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Re: pH Meters - Important Info!
« Reply #15 on: March 04, 2009, 05:15:26 PM »
I really have nothing but good to say about the Extech one I posted above.  I think if I were to not have found the deal I did on that one I would have gotten one of these: Extech ExStick Ph100.

The flat surface electrode is really slick as it can be used in a solution, on a surface, in soil, etc.  I'm not sure of this particular one but they insist you can use directly in the solution, cheese etc. without the worries of leaking electrolytes on the one I have.  You will also be able cut a cheese open and test the pH directly, etc.  Anyway, that is my opinion. Take it for what it is worth!

Ryan


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Offline Cartierusm

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Re: pH Meters - Important Info!
« Reply #16 on: March 04, 2009, 05:28:24 PM »
Two recommendations. First the one I bought is at the high end 98128 by hanna. But since your's 'broke' I would go for a probe style such as Ryan has so you can test the cheese once it's in a wheel. If you can wait buy a handheld off ebay and then a new probe made for food.
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Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #17 on: March 05, 2009, 08:18:16 AM »
Thanks all,  After much internal debate, I have made a decision.
Here is a breakdown of what I considered

I REALLY REALLY wanted to go with the Vernier LabPro and associated pH probe.


Details:
  • Probe type: Sealed, gel-filled, epoxy body, Ag/AgCl internal reference, 12 mm OD
  • cost: approximately $270-$300
  • Response time: 90% of full reading in 1 second
  • Temperature range: 5 to 80 deg C
  • Accuracy: 0.005 pH units
  • No Automatic Temperature Compensation

My Thoughts:  While the thought of exporting data automatically to a laptop and combining it with temperature data really appeals to me, the extravagant nature of this, combined with the fact that this pH meter does not automatically compensate for temperature made me dismiss this.


Then I looked at Ryan's model. The Heavy Duty pH/Temp Kit. All i can say is; Wow.....

  • Dual display for pH or mV and Temperature (°C/°F)
  • Large 1.4" (36mm) LCD display
  • Easy 2 point Cal (pH 7) and Slope (pH 4 or pH 10) adjustments
  • Manual and Auto Temperature Compensation using temperature probe
  • Low Battery Indicator
  • Min/Max/Avg, Auto off and Data Hold
  • Built-in RS-232 PC interface with
  • optional 407001 Data Acquisition Software and 380340 Datalogger
  • Includes meter, mini pH electrode (60120B) with 39" (1m) cable, temperature probe (850188), protective holster with stand, and case.
  • Temperature 32 to 149°F (0 to 65°C)
  • Basic Accuracy ±0.03pH, ±0.5%mV, ±1.8ºF/1ºC
  • Cost: ~$289 (depends on where you go and who you know.....)

My thoughts:
This pH meter is the mack-daddy of all pH meters that I looked at.  This really is a nice rig.  I have not nothing bad to say of it except that I just cannot afford it.  I blew all my discretionary cheese money on Kadova moulds.



So Then I looked at the  Extech ExStick Ph100

  • Built-in Smart chip offers advanced functions and features to a stick style pH meter not found anywhere else
  • RENEW feature that tells you when it's time to replace your pH electrode
  • CAL feature that tells you when it's time to recalibrate your meter
  • Flat Surface pH electrode that is completely waterproof and rugged enough to withstand harsh environments
  • Analog bargraph originates at neutral point (pH 7.00) to conveniently view trends in acidity or alkalinity
  • Temperature measurements with Automatic Temperature Compensation
  • 1, 2 or 3 point calibration
  • Temperature 23 to 194°F (-5 to 90°C)
  • Accuracy ±0.01pH, ±1.8°F/±1°C
  • Cost: ~$89
My Thoughts:

This is a very nice pH probe that does much of what I would like.  The only downside is the large size of the probe.  It looks to be just a bit awkward getting that thing into a small sample cup.
I really like the fact that it self-monitors the state of the probe and the calibration.


What did I go with?

I ended up going with the PH110: ExStik® Refillable pH Meter

  • Refillable pH electrode that can be reused by refilling the reference solution once it depletes
  • Obtains continuous high accuracy using fresh reference solution
  • Fast and easy steps to refill your electrode
  • Eliminates the concern of electrode shelf life
  • Cost: ~$99

This is basically the same pH meter as the PH110, but with an updated pH Electrode

This is what I went with.  I bought from amazon.com

Wayne A. Harris - in vino veritas

Offline chilipepper

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Re: pH Meters - Important Info!
« Reply #18 on: March 05, 2009, 08:40:05 AM »
I sink you choose wisely young grasshopper! :) 

I wonder if Extech will still stand by the fact you can use that directly in the vat if necessary? The refillable reference solution is my only clue there that it must be going somewhere?

Let us know how you like it! 
Ryan

Offline RRR

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Re: pH Meters - Important Info!
« Reply #19 on: March 06, 2009, 10:05:14 AM »
Wayne, thanks for researching this. Is there a reason you picked the 110 rather than the 100. The 100 has a replacable probe, the 110 uses solution. The solution is about 30.00 and the new probe is 50.00. How many times will a bottle of solution replenish the meter? Will there be any need to replace the probe on the 110?


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Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #20 on: March 06, 2009, 10:50:11 AM »
I guess first I should give a bit of background.
My existing Hanna went into Calibration hell.  I had to calibrate it, extensively, multiple times a day.  Perhaps the tip was degraded, perhaps I was doing something wrong, either way, I was frustrated by the whole process. I saw .5 errors in the same sample taken 10 min apart. (whey and wine).  I suspected the tip was the issue

So, when I saw the data sheet for the 110 model I like the part that said.

"Refillable pH electrode is easily serviced. Fresh reference
solution maintains high accuracy
. Eliminates concern with
shelf life"


It hit an understandable hotpoint with me.

I have no data on the lifespan of the solution.  The datasheets indicate the following:
"The supplied container includes 15ml of filling solution. There is enough solution for 4 to 5
refills. Use only the supplied solution for refilling the electrode."


So, when the meter says "renew" or "cal".  I'm all over it.

But this is just my needs.  You may not find that aspect particularly interesting.  And truthfully speaking, there are other, probably better pH probes for cheesemaking.
For example, Hanna makes various dairy-related pH electrodes to be used with their meters here. Some of the listed probes are specific to Cheese, some to milk, others cream/yogurt,  and still others semi-solid milk products.  These probes are are $100-$150 and are meant to be used in conjunction with a pH meter of some type.  For me, those were too specialized and too expensive from a probe replacement perspective.  I need to be able to use this pH meter for other than Cheese applications like wine.

So for me, the ex110 is a good quality (not great) utility-player pH meter/probe that satisfies my specific pH touchpoints and is versatile enough for other applications.

Anyway, sorry to ramble.  Good luck with your decision.



 
« Last Edit: March 07, 2009, 07:59:13 AM by Wayne Harris »
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Offline RRR

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Re: pH Meters - Important Info!
« Reply #21 on: March 07, 2009, 07:56:17 AM »
Thanks Wayne. I've been needing to get into PH but have hesitated because of expense and additional time needed to manage meters. I think I'll give the 110 a go.

Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #22 on: March 07, 2009, 07:58:35 AM »
I will let you all know when i get mine, how i like it.
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Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #23 on: March 10, 2009, 09:24:43 AM »
It came in the mail today!  Woohoo!
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Offline goat lady

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Re: pH Meters - Important Info!
« Reply #24 on: March 13, 2009, 11:45:46 AM »
Just curious do your cheese recipes give you the ph levels needed for each cheese???My books do not even mention ph levels, but they are all raw milk recipes.I' ve following the thread and found it really interesting.


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Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #25 on: March 13, 2009, 12:57:54 PM »
It really depends on the recipe. 

Some do, and some don't.  For example if what you are trying to accomplish during the standardization and acidification of your milk is achieve a pH of say....pH5.7, and that typically takes X number of minutes at a Y number of degrees, a recipe might just say "heat milk to Ydeg for X min"
-or-
It might say, "heat milk to Ydeg for Xmin, pH should be 5.7"
-or-
It might just say "heat milk to Ydeg until pH drops to 5.7"

It really just depends on the recipe.  But the thing to keep in mind is this.  In all cases you are doing the same thing. You are trying to hit a target acidity.  And knowing that, you can start to really play with your own versions of a recipe.


But In many cases a stopwatch will suffice; but over time, one can see how that might not be precise enough. 

I've used this metaphor here in the past; Using a stopwatch to measure acidity during cheesemaking is like trying to stop a car to an intersection that is exactly one mile down a road.  You know in your mind that you can drive 30mph for exactly 2 min and you should be there. But wouldn't it be nice to actually see the stop sign?


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Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #26 on: March 13, 2009, 06:08:49 PM »
An example of cheese made without a pH meter.
This cheese is bad.
Note the pH, the texture, and the taste.  (trust me it was tangy to the point of almost sour)
The pH for finished Cheddar should not be below 5.1
« Last Edit: March 13, 2009, 08:31:47 PM by Wayne Harris »
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Offline goat lady

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Re: pH Meters - Important Info!
« Reply #27 on: March 17, 2009, 10:50:17 AM »
never see cheddar do that looks pretty wet

Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #28 on: March 17, 2009, 11:50:34 AM »
Yep, and wet and nasty.
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