Proper use of PH test strips?

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Homercidal

Homercidal

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So I bought a tube of test strips and after trying them out twice in my mash, I find that they do nothing.

Yep, the color pad looks like a wet pad. No change in color that I can detect. To me this can mean 3 things:

1. I am stupid and don't know how to use the strips.
2. My PH is off the charts.
3. The strips don't work.

All of the colors on the comparison chart are in the range for beer and they are all different enough from the plain strip to make me believe that if the strips were working, and the mash was anywhere near the proper acidity, I'd see a change.
 
Did you buy the cheap ones or the good ones? I bought the good ones from a lab-supply store ($20 instead of $40), and they clearly change color - BUT - and this is a big but - as per a pretty accurate pH meter, their reading is off by a decent amount (about 0.2, maybe 0.4).
 
Mine change color and my mash usually falls in the 5.2-5.6 range according to color, as far as how accurate they are? i would have no idea.
 
I think I bought them at Siciliano's Market in Grand Rapids. I bought them and forgot to use them that batch, then didn't brew for a while and forgot I had them. Got them out for the last batch and was disappointed to see nothing happen. Then tried again with some starsan solution thinking that surely I'd see SOMETHING change, even if it wasn't in the range of the strip.
 
Usually only one end of the strip will actually register a reading, the rest is a just a heavy paper. Make sure you are dipping the correct end in the mash.
 
Last year I bought those exact same strips from the exact same LHBS (sicilianos) and got the exact same results you did. I'm not sure what's wrong with them (or us). I have a pH meter now.
 
Instead of starting a new thread I'll go with this. I bought the colorphast PH 4.0 - 7.0 strips. If I dip them in lemon juice or beer the color will drop to the 4.0 scale which is fine. If I dip them in Portland tap water I don't see a perceptible change in color. As far as I know Portland adds sodium hydroxide to try and maintain 7.8-8.0 ph in the water. So I should see the color at the 7.0 scale. The last time I brewed I used them and did not notice much of any color change.

Am I doing something wrong? Do you think they are defective or the wrong strips in the box or should I just toss them out and buy yet another device?


edit - dunked a strip in Ammonia and it immediately hit the 7.0 color so the strips work on the extremes but not very well in range.
 
Strips aren't of much use in brewing. Do a search and you will find innumerable references to their shortcomings (including in this thread). I'd venture the hypothesis that strips have done more harm to home brewers than good.

The accompanying good news is that the prices of pH meters have gone way down while their performance has gone way up.
 
Lab grade pH test strips are reasonably accurate. Keep in mind that error will be introduced from you trying to determine if the color changed to elf hat blue vs rose blue vs Na'vi blue.
 
See #7. The probability that I am color blind is 100%. I don't do elf hat blue or rose blue. I'm lucky if I can tell it's blue. I'm relying, therefore, I what I see reported. Kai Troester did some extensive testing on these things. You'd have to refer to his website to see about the grade of strips he used. He asked several people to assist him in assessing his results and he did this by photographing strips exposed to various levels of pH next to the scales printed on the bottles, e-mailing these to us and asking us to read them. I couldn't do that, of course, but what I could do was analyze the colors in the photos, construct a calibration curve from the scale and "measure" the pH of the individual strips from that. They were way off RE pH meter readings Kai made.

If you know of strips that do compare favorably to pH meter readings of mash please let the other 95% (i.e. normal color vision) of the readership know what they are.
 
ajdelange said:
See #7. The probability that I am color blind is 100%. I don't do elf hat blue or rose blue. I'm lucky if I can tell it's blue. I'm relying, therefore, I what I see reported. Kai Troester did some extensive testing on these things. You'd have to refer to his website to see about the grade of strips he used. He asked several people to assist him in assessing his results and he did this by photographing strips exposed to various levels of pH next to the scales printed on the bottles, e-mailing these to us and asking us to read them. I couldn't do that, of course, but what I could do was analyze the colors in the photos, construct a calibration curve from the scale and "measure" the pH of the individual strips from that. They were way off RE pH meter readings Kai made.

If you know of strips that do compare favorably to pH meter readings of mash please let the other 95% (i.e. normal color vision) of the readership know what they are.
Click to expand...

Kai's testing was on EMD Colorphast strips which are commonly sold by homebrew shops as high precision strips. At least they don't call them high accuracy.
 
I was going to give it another go on the last brewday, but forgot. At this point I'm going to shoot for a digital tester, but I might try the strips out again before I get it. Maybe the next brew day I will not be pushed for time and will be better prepared to use the strips.

I do not have the colorphast, which I suspect will be better than the generic brand I have. The price of colorphast strips is a good portion of the price of a lower-end digital pH meter.
 
Homercidal said:
I do not have the colorphast, which I suspect will be better than the generic brand I have. The price of colorphast strips is a good portion of the price of a lower-end digital pH meter.
Click to expand...

The generic ones are pretty much worthless IME; all they can tell you is the color of the wort. The ColorpHast strips (based on the survey Kai did, and in which I participated) can be read with reasonable precision, and are fairly accurate once the appropriate offset (+0.3 pH) is applied. This would appear to be some peculiarity of mash chemistry rather than a flaw in the strips' manufacture, since they are accurate in buffer solutions.

You're right that they are a little pricey; by the time you use 300 ColorpHast strips you could have bought a mid-grade pH meter. I would submit that for a home brewer the strips are a practical alternative. At work where I brew 2-3 times a week I maintain a pH meter, but at home where I brew 10-15 times per year I don't personally think it's worth it.
 
Yeah, I am still debating with myself over the cost. At least with a pH meter, I can get better resolution and higher accuracy than with the strips. And I can test my starting water rather than relying on the lab report, which may not be accurate at any given season. Plus, it's one more cool toy to own.

But there is expense beyond just the purchase of the meter, like buffer solution and calibration solution. And I've heard that they can just suddenly "go bad", which would suck.
 
Homercidal said:
But there is expense beyond just the purchase of the meter, like buffer solution and calibration solution. And I've heard that they can just suddenly "go bad", which would suck.
Click to expand...

Stop whining and man up, ph meters are cool! Who want's to guess the color of some cheesy ph strips when you can see an actual lcd readout telling you how awesome you are.

If you can get in on some "bulk" grain buys, I got a crapload of calibration solutions for real cheap. The buffer and cleaning solution I bought will last nearly a lifetime, so it's a onetime expense.



_
 
Here's a pic of my strips after being dipped in wort which read 5.6 on my calibrated digital pH meter.
pHstrip.jpg
 
wildwest450 said:
Stop whining and man up, ph meters are cool! Who want's to guess the color of some cheesy ph strips when you can see an actual lcd readout telling you how awesome you are.

If you can get in on some "bulk" grain buys, I got a crapload of calibration solutions for real cheap. The buffer and cleaning solution I bought will last nearly a lifetime, so it's a onetime expense.



_
Click to expand...
WEST
What Ph meter do you have? Ive been looking for a cheap but good one.
 
I realize this is an old thread, but mabey someone has some new info on ph strips, no one mentions testing the water before the boil! I have read that your water should test at 5.4 for ales and 6.5-7 for darker beers. Is this correct? I have some spring water from 2 different sources and want to test it. Going to wal-mart to see if they sell generic strips.
 
It is, in general, true that if you treat your water with acid to the point that it reaches mash pH (5.4 - 5.6 at room temperature) that you have automatically taken care of the alkalinity of the water. It does not mean that you have taken care of the alkalinity or acidity of the grist. In most cases some additional acid will be needed to prevent the grain from hauling the mash pH back up but in some cases (darker beers though not all dark beers will require it) alkali is needed to neutralize the acidity of the grain. The best bet, of course, is to arrange things so that the pH of the mash (water and grist combined) is correct.
 
RCCOLA said:
Here's a pic of my strips after being dipped in wort which read 5.6 on my calibrated digital pH meter.
pHstrip.jpg
Click to expand...

That's all i freaking got tonight when I brewed. I'm not sure these strips change color. I kept adding 5.2 stabilizer salts and nothing happened. probably put in an extra half tablespoon that didn't need to be there. OG of my triple was supposed to be 1.077 and I got 1.070. After three brews of freaking frustrating strips. I've just about convinced myself to buy a digital PH meter. screw the strips!
 
I ended up buying a Hanna Digital pocket meter and it's been ok. It does tend to drift slightly, but it's stable enough for homebrewing IMO. I don't use it on every batch, I sometimes forget or just don't want to mess with it. If I'm prepared well ahead of time it is quick and easy to use. I just calibrate it as soon as I mash in, then pull a small stainless or glass cup (shot glass) out of the fridge and pour some wort into it. Just a moment after that the sample is down to proper temp and I take a reading. I'm usually testing at about 10 minutes after mashing in. Maybe slightly more depending on how fast the thing decides to accept the calibration solutions. Sometimes it takes it a minute or two.
 
GlassCornbread said:
That's all i freaking got tonight when I brewed. I'm not sure these strips change color. I kept adding 5.2 stabilizer salts and nothing happened. probably put in an extra half tablespoon that didn't need to be there. OG of my triple was supposed to be 1.077 and I got 1.070. After three brews of freaking frustrating strips. I've just about convinced myself to buy a digital PH meter. screw the strips!
Click to expand...

I bought those same strips a couple of years ago and had the same issue. If they did change, the wort discolored the tabs and made them impossible to read. You can check to see if the strips change via pH by A) try dipping in vinegar and/or B) make a solution of 1 tsb baking soda in water and dipping then. Those should get you extremes on each side. I found that the strips for my hot tub worked better than these did... and quickly moved over to a pH meter.

As for the 5.2 buffer, like the strips, I tossed it out. Spend any time here on HBT and you will see hundreds of comments negative to 5.2 stabilizer. It just doesn't work... and I used it until I watched it NOT work with my pH meter, because I am stubborn like that.

I suggest reading the Brew Water Chemistry sticky, and follow the recommendations.
 
Yeah, I just wasted money on these strips as well. Does anyone know if they will work to test if my Starsan solution is still good at least? I hate getting sucked into a bad deal, even if it was just for a few bucks. Maybe one day I will find a use for them.
 
I have found that paper strips are truly unreliable. While I concur that there are plenty of unreliable or short-lived pH meters out there, most will provide a reasonable assessment of pH after they have been calibrated and have proven their stability with the trials that AJ recommends.

Just because you obtained a result with paper strips, it doesn't mean its accurate or reliable.
 

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