Bad pH strips?

[CrazyP]

I bought a vial of 4.6 - 6.2 range pH strips from my LHBS about a year ago but just got around to using them yesterday. I did an all-grain batch and wanted to test the pH of my mash, so I took out a test strip, dipped it for about a second, and then tried to take a reading... The trouble is, nothing happened! These strips go from yellowish-white @ 4.6 to dark brown @ 6.2. There was nothing exotic about my grains or my water... just 2-row with a little bit of crystal 40 and a carapils. The Bru'n Water spreadsheet gave me a pH estimate of 5.3.

The "no color change" result seems to indicate the mash pH is less than 4.6 which I don't believe! Curious, I tried a test strip in pure water, thinking it would turn dark brown, and again I got nothing. I'm wondering if the strips are bad, somehow? I've always kept them in a cool, dark place, but I don't know what they were exposed to before I bought them.

 

[HuskerBrewer]

I had the same thing on my last brew day, but my strips were a lot newer even. Almost no color change in the mash so I tested several of them in tap water where they should turn pretty quick and obviously, but only got a little tinge of purple around the edges. My strips were also stored in my basement brew closet where it's cool, dark, and relatively low humidity. Not sure what happened but I chucked the rest and I suppose I'll have to invest in an electronic pH meter soon.

 

[CrazyP]

Wow, and I was even reading a website saying that the indicator chemicals used are very stable and that's why there is no special sealing or date codes on the package! Sounds like a con job.

 

[Conan]

Try putting them in vinegar, orange juice, or a baking soda/ water mix. The first two are acids, the final is basic. If they don't turn from that they're probably toast. I'm no chemist, though. Kyle

 

[CrazyP]

I'm actually married to a chemist

She spent some time last night doing calculations to figure out how to make a buffered solution in the 4.6 - 6.2 range... The trouble is that most household items like OJ, vinegar, and baking soda are either too acidic or too basic to be anywhere close to the range of the paper... She was going to take them into work today to see if they responded to some pH standards at her place of work, but forgot to bring them.

 

[Wynne-R]

Any chance you have them upside down? It sounds stupid, but it happened to me. The thick part looks like it should be the handle, but it’s the business end.

 

[CrazyP]

Any chance you have them upside down? It sounds stupid, but it happened to me. The thick part looks like it should be the handle, but it’s the business end.

I wish it was that easy, but nope, I was using them the right way.

 

[hophop]

A ph tester is $15 on amazon. It has stayed spot on for months since I calibrated it. Might be cheaper in the long run (And more accurate)

 

[masonsjax]

A $15 meter that has suitable resolution and is reliable enough for brewing? Got a link?

 

[HuskerBrewer]

Any chance you have them upside down? It sounds stupid, but it happened to me. The thick part looks like it should be the handle, but it’s the business end.

That's what I told the SWMBO on our honeymoon...Ba-dum-ching!

Couldn't resist.

 

[mabrungard]

Are they paper strips or plastic? The paper strips are notorious for unreliability and a very finite life.

 

[CrazyP]

Are they paper strips or plastic? The paper strips are notorious for unreliability and a very finite life.

They are plastic actually, and the packaging itself looks relatively new.

 

[tootal]

Double check the instructions. The latest batch we got required you hold it under the liquid for a minute before taking a reading. They seem to work well as we can follow our water treatment as we add a little phosphoric acid at a time.

 

[CrazyP]

Double check the instructions. The latest batch we got required you hold it under the liquid for a minute before taking a reading. They seem to work well as we can follow our water treatment as we add a little phosphoric acid at a time.

It's worth a shot before I toss'em... The instructions actually say to dip for 1-2 seconds and then read after 15 seconds, waiting no longer than a minute to get a reading.

 

[hophop]

A $15 meter that has suitable resolution and is reliable enough for brewing? Got a link?

This is the one I bought. Reads perfect every time when I check the calibration.
Etekcity® PH-009 IA High Quality Digital Pocket Pen Type PH Meter & Digital Tester Hydro New
http://amzn.com/B00CH3QZSE

 

[CrazyP]

$13 right now... For that price there isn't much to lose. Looks a lot like the pH meters I used in high school chemistry labs many moons ago.

 

[masonsjax]

The resolution is pretty low and I don't think I'd entirely trust it for making on the fly adjustments, but for that price, it might be nice for confirming effects of calculated additions.