OK - since I just ordered the meter, I also went back and ordered the buffers. They come with instructions, so maybe I can get on with my new "making wine education" - thanks anyway.

Since I'm presently in between batches, I can't tell you yet what their significance is, but as soon as I become expert, will share with you - that is, if you really want to know.

Bejay

I see that this is a slow forum, but this is a good question for some that was never answered. A pH meter doesn't actually read acidity, it just reads a voltage or a current that is generated between two probes placed in a liquid. Usually, these two probes are combined into one unit. Less sensitive/accurate probes may have some plastic protective casings but some are Very breakable And expensive!

The situation is slightly like trying to read a glass tube thermometer that has slipped in its housing or where the markings have rubbed off. You need the pH buffers, they are usually called 'standards', as reference points to tell you (or the meter) what the voltage represents in pH units. You need at least two different buffers to tell the meter what two voltages refer to. For example you could set the probe in a pH 4.0 buffer and adjust the meter to 4 and then set the probe in a pH 7.0 buffer and adjust the slope; the rate of change in reading, so that the meter now reads 7. You then assume that the probe responds linearly between 4 and 7 which is probably true for a decent probe.

The standards are called buffers because they contain a set of chemicals that will maintain its pH even if small amounts of different pH stuff gets mixed in; air containing carbon dioxide which will make carbonic acid when dissolved in the liquid, for example.

You continue to need the buffers because the probe may or will get clogged up some or a lot, and its response will change. The settings will need to be adjusted. And finally, the buffers will eventually change too and depending on accuracy needed, require replacement.

I'm sorry to be so late in replying to your nice msg. It is appreciated, I assure you.

I'm a novice wine maker - and now have made 3 batches of lime wine (a tree that produces abundantly in the winter months here in California).

Your answer helps to clear up the questions I have. Since lime juice is very acidic, it was necessary for me to learn more about the use of the meter. I hope I read your post OK. I note also, that I need to be very careful in the use of the different buffers, so they don't become contaminated.

Incidentally, I'm doing quite well with "Skeeter's Pee" as it is referred to. I found the recipe on the "net" and have learned a lot, especially because we have so much fruit.

I have planted some Chardonnay grapes, and they are looking great. Hopefully, in time I will be able to get some of my favorite wine - made at home.

bejay

Hi bejay: I hope things are working out for you. I don't recall why I looked at the Wine forum and saw your post. As you can now see, I don't browse here. Thanks for your actually very quick response. Sounds like you have things under control. I doubt that wine requires really accurate pH readings, but yes, you shouldn't contaminate the buffer solutions with the wine or the other buffer solution. Normally, you would keep a squirt bottle of water next to the pH meter to rinse the probes into a spare beaker or bowl or sink etc, before changing from one buffer or wine sample to another.

You need to store the pH meter "wet". Storage solution is used for this as allowing the probe to dry out can compromise the unit.