pH Meter - Correct Use

[iratherfly]

Hi All,
OK, getting more serious about the harder cheeses I figured it would be essential to use a pH meter. I got Hanna Checker 1 but not quite sure how to use it. Some of the questions below may seem utterly dumb to you, but I just can't figure this out - never used one of these.
The meter came with a 7.01pH buffer solution to calibrate but instructions say I need additional 10.1pH or 4.01pH buffer solution to complete calibration so it seems that I have a useless unit until I purchase this other solution. It also seems that once opened and used the buffer solution I need to throw it away and buy another one.

• Should I just get giant bottles of these solutions so that I can reuse in small quantities each time I buffer? What does everyone here do?
• Can one calibrate using the 7.01pH solution only? Is buffer solution temperature very important for accuracy?
• The electrode tip has this smudge of crystals of who-knows-what on it. If I put it in water (or milk), these wash off onto the liquid and some residue floats on it. I am afraid of cheese contamination from this residue. I am also weary of similar contamination from buffer solutions. Do I need to wash the electrode thoroughly in water after I buffer and before each use?
• It seems that to take measurement, I must take of the cap and dip the tip 1" in the milk until I get a stable number. Is that correct? If so, how am I suppose to take measurements from a firm molded cheese? I can't possibly puncture 1" holes in the cheese with the electrode. What do you do?
• Am I suppose to take the electrode off in between uses and store it in water or solution?

[swh]

iraterfly,

Having just gone through my first purchase of a ph meter, where the first one was defective, I learned a lot talking to techs and the great folks in the forum. I also failed to get 4.0 and 10. buffer and depending on the unit your accuracy will drift the further away from 7.0 if you only do a one point calibration. I believe it depends on the units. I'm using a ExTech PH110 and it will do one point calibration but is not accurate out of the 7.0 bound if only calibrated there.

You can either buy bottles of buffer and have then for the long haul, get it in one shot packets or powder and mix your own.  I'm to lazy to mix my own. The Science Company http://secure.sciencecompany.com/pH-Buffer-Solution-701-20ml-P6399C703.aspx has them. It's a cost vs convenience thing.

Don't worry about the crystals I believe they are put there to protect the electrode by the manufacturer. My unit recommended soaking the tip in 4.0 for 10 minutes prior to calibration. Some recommend distilled water.

You don't want to use the meter directly in the whey but pull some out with a pipet (or the stand in turkey baster) and sample from a clean container. You said your unit needs to be immersed an inch in the sample. My electrode is fine with  under 1/4 inch or so. I'd check the unit

In terms of direct sampling of cheese, you really want to be sampling whey in the majority of situations. There has been a thread on how to take a curd sample and turn it into a mush (emulsify?).

Hope this helps, good luck

Cheers, Steve

[iratherfly]

Thanks Steve, this is very helpful!
So from now on I will take samples to test the ripening milk and fresh curd.
I wonder however if a reading taken from whey of a cheese after it drained overnight will be similar to the pH level of the cheese from which it drained. I have a feeling it won't. - what do you think?

I will buy some calibration solution now - thanks!

[Lennie]

I bought a Hanna pH meter myself not long ago.  As an analytical chemist I knew what to buy.  I bought a bottle of the storage solution, this is indispensible for maintaining the probe as long as possible.  I also bought some of the packets of buffer.  I put one each of pH 7.0 and 4.0 in their own small bottles with a tight lid.  They'll stay good for quite awhile this way.

I conditioned my probe for two hours in the pH 7.0 buffer the first time I used it, this is what my directions said.  Then I calibrated with 7.0, then 4.0.  It seems to hold the cal pretty well, before I use the meter I check it against both pH buffers.

After I use it (I stick the thing directly in the pot) I rinse it under the sink to remove the gunk, then I dab it on a soft towel (don't twist, you don't want to scratch the bulb) then I dip it in distiller water before putting it back in the bottle with the storage buffer.  I actually made a bottle with storage buffer too, rather than using the stock bottle.  This keeps the main bottle from getting contaminated.  Sometimes a little something will grow in a buffer solution.

Good luck, Imy pH meter has already paid dividends with a couple of good balls of mozzarella.

[iratherfly]

Thanks! Very helpful!
I am still having issues figuring out how to measure hard cheese the morning after without making a hole in it. Hmmm...
Will get the other solutions and extra storage bottles for them and for the probe too. Thanks for the advise!

[DeejayDebi]

Very hard with a general purpose probe or all in one unit. They make special probes with pencil like tips for chese and meats or other things that need poking. I posted some close ups of different probes

Here

[iratherfly]

Thanks! That's cool. I suppose I can connect the Jenco JE175P Spear Tip pH Probe to the Henna because it's BNC? Where do you get those probe savers?
I have to say that thus far the whole thing still seems kind of improportionally tedious. Lots of work to keep this, maintain this calibrate over and over, make sure the solution temp is right when calibrating, figuring out if the milk temp had affected the pH reading, ordering liquids, throwing away old liquids, finding some storage for the probes that would suspend them in liquid, not spill yet not cover them and mess up the connectors. This is like owing another pet. Is it really worth it?

[linuxboy]

It is worth it if you want to be serious about cheesemaking and not waste milk experimenting. It is also worth it when you don't have a mentor who can guide you and tell you the specific points in the milk where you should take the next step, such as heating, or whey drain. It is also worth it if you want to make multiple cheese styles, because going from a cheddar to a brie is a drastic change, and you need to build experiential memory for when to take action in the cheesemake. pH is not magic... it's just a tool that has precision. Great cheese has been made without meters, and will continue to be made without them, but in most of those cases, apprentices were taught with hands-on knowledge and make a specific cheese style, or two. This is one area where a home cheesemaker can take some shortcuts to the traditional knowledge apprentices learned... and with less gruntwork

[iratherfly]

Thanks Linuxboy. As modern home cheese makers we have the privilege of gaining enough knowledge to do Alpine, Greek, Mexican and Dutch cheeses in a single day - unprecedented in 3000 years of cheesemaking history. We can watch videos and photos online, help each other out instantly, obtain proper equipment and get lab quality cultures - not to mention instant-read instruments. In the old days, a 7th generation Greek Feta maker didn't have a first clue or instincts about Gouda making. The fact that we have access to this enormous cross knowledge is amazing, but yes - it also means that we have to develop different sets of instincts for different cheeses, and sometimes instrumentation does the work.

I suppose I have to look at pH readings as my training wheels for harder cheese. That's a good thing. (I am growing quite comfortable with my softer/younger cheese instincts). My only issue is ...must I fall off a bike with the training wheels on it before I learn how to use the training wheels?

2 weeks ago, my Tomme got that .2 pH drop but couldn't get a clean break on time. I then missed the curd draining because I waited for the pH reading to stabilize for 10 long minutes, I then jabbed a small hole in my cheese with the probe to test it the next morning, and for the first time in cheesemaking history, I actually got a brine wrong because of a wrong pH reading. All of that was because I relied on a pH meter and not my instincts (which I admit are still poor).  Perhaps I anticipated this would be as easy as an instant-read thermometer, but it's obviously not. I do however realize that without pH readings there is no guarantee that this cheese would turn out okay 3 months down the road so I do want to learn to do it right. I just don't want to rely on instruments that are more laborious, pesky and questionable than my curd... does that make sense?

[DeejayDebi]

I think the meter and such are a nice visual key to what's going on but I fly by instinct 99.9999% of the time. The pH meter is more for curiousity for me than anything. I think of all the cheeses I've done over the years I've use the pH meter 4 times. Just not in the habit of using it for cheese. I find when I am ready to move to the next step I've used it  check to see if the meter agrees with me or I use it when someone is looking for more information.

I would think you could use the probes with your Hanna. Mine stated any BNC type probe would work unless specidically designed for an particular meter. I got the probes Here

The general purpose probes aren't to bad but the spear tipped are pricey. They are made for cheese and meat.

I posted some more info on pH meters and stuff in the library. Got A few more when I find them.

Oh and the probe savers come with the probes - but you have to buy the test solutions.

[iratherfly]

Thanks Debi, wow - that is a lot of money spent on instruments that you don't really use much. You and I talked about meat curing before. Are you using them in any connection to that at all?

[Lennie]

It is also worth it when you don't have a mentor who can guide you and tell you the specific points in the milk where you should take the next step, such as heating, or whey drain.

You and the others here are excellent mentors.

[DeejayDebi]

I actually started using the pH meters when I started making fermented sausages and beer. Never used them for cheese until this year when I found Johns forum. Actually had no idea what the ranges would be with cheeses. The books I had merely mentioned pH readings never what they were. Most were from the early 70's. I just have to get in the habit of using them for cheese as well - old habits die hard!