Spike Brewing 12.5 Conical Fermenter Giveaway!

Home Brew Forums > Home Brewing Beer > Brew Science > Proper use of PH test strips?

Reply
 
LinkBack Thread Tools
Old 11-19-2010, 05:08 PM   #1
Homercidal
Moderator
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
Homercidal's Avatar
Recipes 
 
Join Date: Feb 2008
Location: Reed City, MI
Posts: 23,236
Liked 2021 Times on 1453 Posts
Likes Given: 1108

Default Proper use of PH test strips?

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.

__________________
Homercidal is offline
 
Reply With Quote Quick reply to this message
Old 11-19-2010, 05:11 PM   #2
the_bird
10th-Level Beer Nerd
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
the_bird's Avatar
Recipes 
 
Join Date: May 2006
Location: Adams, MA
Posts: 20,487
Liked 361 Times on 297 Posts
Likes Given: 95

Default

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).

__________________
Come join Yankee Ingenuity!

"I'm kind of toasted. But I looked at my watch and it's only 6:30 so I can't stop drinking yet." - Yooper's Bob
"Brown eye finally recovered after the abuse it endured in Ptown last weekend, but it took almost a full week." - Paulie
"no, he just doesn't speak 'stupid'. i, however, am fluent...." - motobrewer
"... I'll go both ways." - Melana

That'll do, Pigley. That'll do.
the_bird is offline
 
Reply With Quote Quick reply to this message
Old 11-19-2010, 05:13 PM   #3
smakudwn
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
smakudwn's Avatar
Recipes 
 
Join Date: Mar 2009
Location: St.Charles, MO
Posts: 1,001
Liked 46 Times on 35 Posts
Likes Given: 6

Default

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.

__________________
smakudwn is offline
 
Reply With Quote Quick reply to this message
Old 11-19-2010, 06:14 PM   #4
Homercidal
Moderator
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
Homercidal's Avatar
Recipes 
 
Join Date: Feb 2008
Location: Reed City, MI
Posts: 23,236
Liked 2021 Times on 1453 Posts
Likes Given: 1108

Default

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.

__________________
Homercidal is offline
 
Reply With Quote Quick reply to this message
Old 11-20-2010, 02:55 AM   #5
Paddle_Head
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2009
Location: Hudson Valley of NY
Posts: 112
Liked 1 Times on 1 Posts

Default

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.

__________________
Paddle_Head is offline
 
Reply With Quote Quick reply to this message
Old 11-20-2010, 07:52 PM   #6
-TH-
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2008
Location: Zeeland, Michigan
Posts: 975
Liked 59 Times on 35 Posts
Likes Given: 2

Default

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.

__________________
TH

Builds, etc: E-Brewery | Pneumatic Bottle Capper | Fermentation Chamber | Stirplate | Bottle Cabinet
Water Spreadsheet: www.EZWaterCalculator.com
-TH- is offline
 
Reply With Quote Quick reply to this message
Old 11-20-2010, 08:51 PM   #7
ajdelange
Senior Member
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: McLean/Ogden, Virginia/Quebec
Posts: 5,803
Liked 563 Times on 464 Posts
Likes Given: 15

Default

Quote:
Originally Posted by -TH- View Post
I'm not sure what's wrong with them (or us).
Well, the probability that one or the other of you is color blind is 9.5% but the probability that you both are is 0.25% so I guess that's probably not it.
__________________
ajdelange is offline
AnthonyD Likes This 
Reply With Quote Quick reply to this message
Old 05-29-2011, 04:47 PM   #8
samc
Feedback Score: 1 reviews
Recipes 
 
Join Date: Aug 2008
Location: Portland OR
Posts: 5,420
Liked 54 Times on 51 Posts
Likes Given: 29

Default

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.

__________________
samc is offline
 
Reply With Quote Quick reply to this message
Old 05-29-2011, 07:55 PM   #9
ajdelange
Senior Member
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: McLean/Ogden, Virginia/Quebec
Posts: 5,803
Liked 563 Times on 464 Posts
Likes Given: 15

Default

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.

__________________
ajdelange is offline
 
Reply With Quote Quick reply to this message
Old 05-29-2011, 08:24 PM   #10
coryforsenate
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jul 2009
Location: College Station, TX
Posts: 327
Liked 4 Times on 4 Posts
Likes Given: 2

Default

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.

__________________
Bottled
Merlot Barrel Russian Imperial Stout
Vanilla Belgian Stout
Hefeweizen
Hard Cider
Tripel w/wine tannins
Weizenbock


Primary
Dark Strong
Tripel
coryforsenate is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Proper use of a pH meter EvilBrewer Brew Science 18 12-21-2010 06:01 PM
Can labs test for chloramine or perchlorate? wuertele Brew Science 8 09-29-2010 05:19 AM
Water Test Results stigs Brew Science 2 09-21-2010 05:55 PM
Force Test on Wort ipscman Brew Science 8 01-28-2010 02:37 AM
Wort stability test Piotr Brew Science 2 07-01-2009 04:46 PM