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GENERAL CHEESE MAKING BOARDS (Specific Cheese Making in Boards above) => EQUIPMENT - Making Cheese => Topic started by: Cartierusm on February 16, 2009, 09:08:35 PM

Title: pH Meters - Important Info!
Post by: Cartierusm on February 16, 2009, 09:08:35 PM
Ok, I've said this a few times in other posts but thought I would start a new thread to make sure people understand.

YOU HAVE TO TAKE A SAMPLE. You can't put the meter directly in the milk. I just got off the phone with Hanna Instruments for the second time and this guy knew what he was talking about. The electrode PH meters use leak electrolites into the sample. He said it's a very minute amount but shouldn't be used in the actual batch. You have to take a sample out, test it and then throw the sample away.

Just for a little more info, although I have a really expensive PH meter it doesn't go down to .01 decimal places, so I was going to get the one Wayne and Dave have, but the guy at Hanna said it doesn't have temperature correct. This means if the sample is anything other than 69.8 the PH will be off a little. Here is the temperature correction chart.

If your sample is 86F subtract .01, so if it reads 7.01 on the meter it is really 7.00.
86 = -.01
95 = -.02
104 = -.03
113 = -.03
122 = -.03
131 = -.03

Title: Re: pH Meters - Important Info!
Post by: Likesspace on February 17, 2009, 02:15:54 AM
Carter, this is great information but also not GOOD information for me!
For one, I was dipping my meter into the milk and curd the entire way. Do you think this could have contaminated my cheese?
Also, when you say "If the sample is anything other than 69.8" are you talking about the fresh milk reading?
Now you've given me something to worry about.
I really appreciate the information (and especially the temperature correction chart) but this concerns me.

Dave
Title: Re: pH Meters - Important Info!
Post by: homeacremom on February 17, 2009, 02:20:31 AM
I think that would mean if the sample is anything other than 69.8 degrees F.... That particular meter is calibrated for 69.8 degrees and doesn't automatically adjust for temperature.
Title: Re: pH Meters - Important Info!
Post by: Likesspace on February 17, 2009, 02:29:13 AM
Okay, that makes sense. Sheesh I can be dense at times.
Tanks H.A.M.
I appreciate it.
Sounds as if it will be a bit of a pain using my meter in the future but I guess not overly so.
To me the temperature correction will not be nearly as big of a pain as having to remove a sample before each test.


Dave
Title: Re: pH Meters - Important Info!
Post by: Cartierusm on February 17, 2009, 03:36:12 AM
Dave the guy at Hanna said it's a minute amount and should be avoided but probably won't hurt. He said definately don't do it in the future, always take a sample. Ham is right you're meter is calibrated for room temp. You should always take the reference sample when the milk has come up to temp 86F or so, because sometimes mine changed without adding starter. Starts out at 6.9 and then goes to 6.7 before adding starter.
Title: Re: pH Meters - Important Info!
Post by: chilipepper on February 17, 2009, 11:30:09 PM
I ordered one of these pH electrodes (http://www.extech.com/instruments/product.asp?catid=73&prodid=470) last week and they insist it will be fine for direct contact with both the raw milk and the cheese at all phases of production.  The really nice thing about it is that it is a flat surface electrode and will not need to necessarily be submerged to take a reading.  The other bonus is that it is also not made of glass for the risk of breaking and ruining a batch of cheese.

Quote
Hello Ryan,
The 601100 electrode should not leak electrolytes into your sample. You can place the electrode in your vat, just don’t place more than the white shaft in the liquid, and be sure to wipe the electrode before and after measurements.

Thanks,

Best Regards
Jamie Cohen
EXTECH Technical Support

Title: Re: pH Meters - Important Info!
Post by: wharris on February 17, 2009, 11:33:21 PM
what unit does it connect to?
Title: Re: pH Meters - Important Info!
Post by: Cartierusm on February 17, 2009, 11:54:54 PM
hee hee you said unit.

Wayne I think it is a universal BNC and will work with any hand held such as http://morebeer.com/view_product/18715//Milwaukee_pH_Meter_w_ATC (http://morebeer.com/view_product/18715//Milwaukee_pH_Meter_w_ATC)

But wayne if you're going to follow in my footsteps and use TA then you have to take a sample anyway. If I only had to do PH then maybe I'd consider it.

Incidently I figured out a way to measure down to 20th of 1 ml, I use an eyedropper and measured it's water drops and I get 20 for 1 ml. So I can get real accurate.
Title: Re: pH Meters - Important Info!
Post by: chilipepper on February 18, 2009, 12:15:01 AM
I actually scored one of these:

(http://www.extech.com/instruments/resources/images/407228.jpg)

Heavy Duty pH/Temp Kit (http://www.extech.com/instruments/product.asp?catid=40&prodid=447)

Which is really cool because along with my score it has the software that will log both temp and pH to an Access database.  Plus it has cool little on screen gauges and graphs, etc. The electrode was not included, hence the reason I ordered the one above.  Should be pretty cool and stay tuned for graphs of pH over time included with my cheesemaking posts! :)
Title: Re: pH Meters - Important Info!
Post by: Cartierusm on February 18, 2009, 01:30:09 AM
Dammm we've created a monster. Now all you need chili is an automatic titration station for measureing Titratable Acids from Hanna.

Wayne, uhhh, I hate to tell you this but Chili beat you to the punch for that idea we were talking about the other day. He's in ND maybe you can borough it... :D
Title: Re: pH Meters - Important Info!
Post by: wharris on February 18, 2009, 01:33:16 AM

Its not the size of the probe that counts, its how you use it.

;)

Title: Re: pH Meters - Important Info!
Post by: Cartierusm on February 18, 2009, 01:35:51 AM
Well Wayne kind of went there, and I probably shouldn't so I won't I'll be good.
Title: Re: pH Meters - Important Info!
Post by: LadyLiberty on February 18, 2009, 09:11:16 AM
I will resist as well.

But you know, when I was reading this thread, I realized: We are a bunch of true nerds!
Title: Re: pH Meters - Important Info!
Post by: Cartierusm on February 18, 2009, 10:43:34 PM
Speak for yourself Oh Hyperborean Wanderer.
Title: Re: pH Meters - Important Info!
Post by: wharris on March 04, 2009, 07:14:46 PM
Well, my little Hanna pH meter just crapped out. 

So, this batch (yet unposted) will yeild zero pH data. 

Damn.

Thoughts?  I am really ready to get a NICE one.  (well, lets not go too crazy), but I am open to sugestions.

Title: Re: pH Meters - Important Info!
Post by: chilipepper on March 04, 2009, 11:15:26 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 (http://www.extech.com/instruments/product.asp?catid=40&prodid=430).

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
Title: Re: pH Meters - Important Info!
Post by: Cartierusm on March 04, 2009, 11:28:24 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.
Title: Re: pH Meters - Important Info!
Post by: wharris on March 05, 2009, 02:18:16 PM
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 (http://www.vernier.com/mbl/labpro.html) and associated pH probe (http://www.vernier.com/probes/ph-bta.html).
(http://engineering.vernier.com/images/interfaces/labpro.jpg)
(http://chariot.vernier.com/images/products/ph-bta_web.jpg)
Details:

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 (http://www.extech.com/instruments/product.asp?catid=40&prodid=447). All i can say is; Wow.....
(http://www.extech.com/instruments/resources/images/407228.jpg)

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 (http://www.extech.com/instruments/product.asp?catid=40&prodid=430)
(http://instrumentation2000.com/ProductImages/extech/ph100.jpg)
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 (http://www.extech.com/instruments/product.asp?catid=40&prodid=431)


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 (http://www.amazon.com/Extech-EXSTIK-WATERPROOF-REFILLABLE-Product/dp/B0012W2NWS/ref=pd_bbs_sr_1?ie=UTF8&s=hi&qid=1236262287&sr=8-1)

Title: Re: pH Meters - Important Info!
Post by: chilipepper on March 05, 2009, 02:40:05 PM
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
Title: Re: pH Meters - Important Info!
Post by: RRR on March 06, 2009, 04:05:14 PM
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?
Title: Re: pH Meters - Important Info!
Post by: wharris on March 06, 2009, 04:50:11 PM
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 (http://www.hannainst.com/usa/prods2.cfm?id=002005). 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.



 
Title: Re: pH Meters - Important Info!
Post by: RRR on March 07, 2009, 01:56:17 PM
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.
Title: Re: pH Meters - Important Info!
Post by: wharris on March 07, 2009, 01:58:35 PM
I will let you all know when i get mine, how i like it.
Title: Re: pH Meters - Important Info!
Post by: wharris on March 10, 2009, 02:24:43 PM
It came in the mail today!  Woohoo!
Title: Re: pH Meters - Important Info!
Post by: goat lady on March 13, 2009, 04:45:46 PM
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.
Title: Re: pH Meters - Important Info!
Post by: wharris on March 13, 2009, 05:57:54 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?


Title: Re: pH Meters - Important Info!
Post by: wharris on March 13, 2009, 11:08:49 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
Title: Re: pH Meters - Important Info!
Post by: goat lady on March 17, 2009, 03:50:17 PM
never see cheddar do that looks pretty wet
Title: Re: pH Meters - Important Info!
Post by: wharris on March 17, 2009, 04:50:34 PM
Yep, and wet and nasty.