PH meter buffering solution

[Kev R]

Hi
Instructions for calibrating my meter call for solutions of 4.01 , 7 and 10.01.
I have solutions of 4,7 and 10. how important are the .01s.
thanks
Kev

 

[Mardoo]

If you have a shit-hot testing-lab-grade bench pH meter, maaaaaaaaybe. Otherwise it's not going to affect your life as a homebrewer.

 

[MHB]

For brewing the 7 & 4pH is all you need.
Ideally you calibrate across the range you will be working over, or in that direction so for brewing which is on the acid side from Neutral (7pH) to Acid (4pH).
The 0.01's are going to be temperature dependant.
The solutions I use says pH 4.00 +/- 0.02 at 25oC and they have a table on them that shows how temperature affects the pH.
On the table at 5oC pH is 4.00, at 50oC pH is 4.06
So if you have quality standards and are working at or around 25oC, don't worry about the 0.01's
Mark

PS I buy mine at Australian Scientific at Kotara, They sell 0.5 & 1L bottles and the prices are pretty reasonable with my 1L bottle being just under 1/2 full after a couple of years.
M

 

[Kev R]

Thanks
So even though the instructions say to use 3 solutions it's ok to only use 2

 

[Danscraftbeer]

Mine has the option to use one of, or both 4 and 7. Using both is to be more precise but often I just use the 4.

 

[MHB]

Thanks
So even though the instructions say to use 3 solutions it's ok to only use 2

I would be using the 7 and 10 if I were measuring alkaline solutions, I strongly suspect that if you read the instructions that came with the pH meter they will say you need to have all three, but to use the two that are appropriate to the range you are working in.
I have never seen a pH meter where all three standards would be used as a matter of course. Could be but do reread the instructions.
Mark

 

[damoninja]

For brewing the 7 & 4pH is all you need.

Unless you're talking sours.

 

[MHB]

Unless you're talking sours.

Never seen a standard for calibration lower than 4pH, you would still be working in the Acid range and using the same 7/4pH buffers.
Or are you just making random observations?
Mark

 

[damoninja]

Never seen a standard for calibration lower than 4pH, you would still be working in the Acid range and using the same 7/4pH buffers.
Or are you just making random observations?
Mark

Ah for calibration? I thought you meant you'd never need to measure something below 4.

 

[MHB]

Strange as it might seem, the lowest pH's if find are in Cider (mid to high 2's) knocking that down to around 4-4.2pH makes a big difference to the flavour, Potassium Bicarbonate is the go.
Mark

 

[damoninja]

Strange as it might seem, the lowest pH's if find are in Cider (mid to high 2's) knocking that down to around 4-4.2pH makes a big difference to the flavour, Potassium Bicarbonate is the go.
Mark

Last cider I did I measured pH of 3.5, compared to some lemons I'd just juiced which were 2.5 that's pretty bloody sour.

 

[MHB]

Getting the pH right gives a much fuller flavoured Cider, its well worth trying, even if you just test it in a glass.
You can get away with using Sodium Bicarbonate (baking soda) but the Potassium salt works a lot better.
Mark

 

[peteru]

Unless your taste buds have an increased sensitivity to potassium salts. I find that it gives me a metallic/soapy flavours. It's particularly bad when used as a meat brine (for reduced sodium claims), but it taints beverages too.

 

[LiquidGold]

Strange as it might seem, the lowest pH's if find are in Cider (mid to high 2's) knocking that down to around 4-4.2pH makes a big difference to the flavour, Potassium Bicarbonate is the go.
Mark

Interesting... I use potassium bicarbonate in my aquaponics to add potassium and raise pH. I'll be keeping that in mind and testing pH next time I make a cider.

I actually cheat to calibrate my pH meter I simply check it against my water test kit and make sure it reads the same. Probably not the most accurate or scientific method but seems to do the trick.

 

[Danscraftbeer]

Interesting... I use potassium bicarbonate in my aquaponics to add potassium and raise pH. I'll be keeping that in mind and testing pH next time I make a cider.

I actually cheat to calibrate my pH meter I simply check it against my water test kit and make sure it reads the same. Probably not the most accurate or scientific method but seems to do the trick.

Actually I've been dumbfounded at the variance of pH testing the water of my Aquaponics.
API pH water test compared to the AD11 probe. I cant make sense of the variances but I will consider the AD11 calibrated properly over the API test kit.
The AD11 probe reads a lower pH more often than reading the same as the API color test.

I think the water colour testing is variable to other things.

 

[LiquidGold]

Yeah you're right, water temperature being the most obvious one but I wouldn't be surprised if there are other variables.

Guess I'd be better off using a buffering solution after all, mind you I'm only using a cheap pH meter.

 

[Danscraftbeer]

Yeah you get what you pay for.
If your more concerned about getting better accuracy on pH then inevitably you have to pay more for better equipment.
I payed ~ $200 to get to know my brewing/mash techniques over 16 months of brewing. That pH meter has now past its usable time but I learned the right chemistry. I want another test probe now but its a luxury expense to confirm what I already know etc.

 

[fungrel]

PS I buy mine at Australian Scientific at Kotara, They sell 0.5 & 1L bottles and the prices are pretty reasonable with my 1L bottle being just under 1/2 full after a couple of years.
M

Nice tip, i buy 250ml bottles and was looking for something cheaper.

From memory my cheap meter seems to want 4.01 etc as well, and they can be bought in the dry packets from ebay.

The more expensive version that i bought only asks for whole numbers.

I don't think it would matter on the homebrew level. 0.01 isn't much of an issue.

 

[Bonenose]

The 4.01 and 7.01 are standard buffers traceable to NIST standards I think it is. Not really an issue unless you are calibrating process or lab instruments. What you need to watch is temp of your buffer keep at 25 degrees if possible then pH of 4 should cal at 4 etc. Also rinse your probe with good distilled water or the buffer you are about to use, ideally with both if you can. Don't be scared to cal two or three times if still out when you check your meter against a buffer and it is out.

 

[Bonenose]

Thanks
So even though the instructions say to use 3 solutions it's ok to only use 2

Ideally a three point cal will give better accuracy across the full range of the meter but if only measuring around 4 to 7 then two point with them will work fine.