21 replies to this topic

[Big Nake]

I saw this on Northern Brewer and big ups to Denny for posting THIS of a conversation that started with Martin Brungard. It suggests that ColorpHast strips cannot just be "dipped" into the mash for a second or two and then read. It needs to be submerged for much longer than that to get an accurate reading. Never, ever heard that before. Thoughts?

Edited by KenLenard, 12 January 2013 - 12:44 PM.

[denny]

My only thought is that if Martin says it, I believe it.

[Big Nake]

My only thought is that if Martin says it, I believe it.

I wouldn't have posted it otherwise. In Martin we trust.

[MyaCullen]

I wouldn't have posted it otherwise. In Martin we trust.

my strips ( adifferent brand) instruct 1 minute of immersion

[Brauer]

I've used colorpHast strips for probably 20 years or more and I believe the instructions have always said that they should be immersed for a minute or more. I was concerned about this, so I tested a few immersion times from ~10 seconds to ~2 minutes. I did this in the lab with a range of inorganic buffers from pH 5.0-6.0, comparing the results to a high quality, fully calibrated pH meter, then I repeated it on two different brew days with a pale and a dark wort and I measured identical pH no matter how long I submerged the strip.I decided that I wouldn't worry about how long I submerged the strips, though I do count to 10 for good luck. I'd be curious to hear other brewers' results from any similar test.

[Big Nake]

I've used colorpHast strips for probably 20 years or more and I believe the instructions have always said that they should be immersed for a minute or more. I was concerned about this, so I tested a few immersion times from ~10 seconds to ~2 minutes. I did this in the lab with a range of inorganic buffers from pH 5.0-6.0, comparing the results to a high quality, fully calibrated pH meter, then I repeated it on two different brew days with a pale and a dark wort and I measured identical pH no matter how long I submerged the strip.I decided that I wouldn't worry about how long I submerged the strips, though I do count to 10 for good luck. I'd be curious to hear other brewers' results from any similar test.

Interesting. What I have seen is this... one dip for a couple seconds and maybe a high pH. So maybe ½ ml of lactic acid, stir, measure again with a quick 1-2 second dip of another ColorpHast strip. You can clearly see that the second strip is "lighter" showing a lower pH. This is not scientific, clearly but they do seem to work & show consistent results on a quick dip.

[SchwanzBrewer]

I forget which brand I have, but it says 2 seconds dip. I found that doing that the color never really changes. Longer dip time is required.

[positiveContact]

I've used colorpHast strips for probably 20 years or more and I believe the instructions have always said that they should be immersed for a minute or more. I was concerned about this, so I tested a few immersion times from ~10 seconds to ~2 minutes. I did this in the lab with a range of inorganic buffers from pH 5.0-6.0, comparing the results to a high quality, fully calibrated pH meter, then I repeated it on two different brew days with a pale and a dark wort and I measured identical pH no matter how long I submerged the strip.I decided that I wouldn't worry about how long I submerged the strips, though I do count to 10 for good luck. I'd be curious to hear other brewers' results from any similar test.

I do about 30 seconds. I just let it sit there while I take temp readings at various locations in the cooler. Since I always seem to hit my target pH I figure they are working.

Edited by StudsTerkel, 13 January 2013 - 07:02 AM.

[zymot]

I have to wonder the how important time is in creating an accurate color against how accurate we are at comparing the strip to the color chart.Maybe the exact perfect and correct period of time (what that turns out to be) will produce a more accurate color, but you still hold the strip up against a handful of color squares and say, "Yep, it looks like it is between 5 and 6."

[Big Nake]

I have to wonder the how important time is in creating an accurate color against how accurate we are at comparing the strip to the color chart.Maybe the exact perfect and correct period of time (what that turns out to be) will produce a more accurate color, but you still hold the strip up against a handful of color squares and say, "Yep, it looks like it is between 5 and 6."

Also true. On the version of the strips that go from 4 to 7, there is a pretty good key that goes in increments of .3 and comparing them is pretty easy. But I would agree that it comes down to the brewer's estimation and ability to determine where the pH falls according to the color. When I got into a heavy conversation about strips vs. meters (where quite a few people said that ALL of the strips are unreliable), many, many good brewers said that for our purposes, good strips (like ColorpHast) are all that you need. When I was peeved about my ability to accurately measure mash pH and thought about getting a meter, many of those people said that getting a meter was fine but just not necessary to determine the pH of a mash. I have a relatively new box of ColorpHast strips and will contibue to use them. Next time I'll do a "longer dip". Cheers.

Edited by KenLenard, 13 January 2013 - 09:54 AM.

[pizzaman]

Meters are great but they are kind of a hassle to keep calibrated and in good working condition. Then the probe will go out on you. the strips work well enough for a lot less effort. Same with pool testing. They make strips that will give you all most all the information you need compared to mixing chemicals to test. Maybe not quite as accurate but they work well and tel you when you might have a problem. The instructions on those say 15 second dip and wait 30 seconds to read.

[Big Nake]

This morning I'm making a blonde ale. I got the water and additions set up and saw that the water would be good for beers in the 8-13 SRm range. The blonde comes in at 5. This is not unusual as I might just lower the pH of the mash down the rest of the way with lactic acid. As I put the ColorpHast strip into the mash, I remembered this thread and left it in there for 60 seconds. It was quite a bit darker than usual and darker than I expected. It required a little more lactic acid to get the pH into the 5.2 - 5.3 range. Not sure if this is just fooferall but I now wonder if the "quick dip" was not accurate and if I have been mashing at higher-than-optimal pH. I know Brauer said that he did some nice research and found little change in the strip based on time submerged but he also said that he counts to ten which is about 9 seconds longer than I had been doing it. I would literally just dip and remove... I'll bet I wasn't getting an accurate reading.

[positiveContact]

yeah - I think more than 1 second is required. I don't know the minimum but 10 seconds is probably fine as well.

[Big Nake]

Oh, and I now see that I stated Northern Brewer for Denny's thread when it was actually Homebrewersassociation.org. My apologies.

yeah - I think more than 1 second is required. I don't know the minimum but 10 seconds is probably fine as well.

I'm going to be keeping an eye on this. Over the past few years I have been using ColorpHast strips and have gotten to know where a lot of my beers come in as far as pH is concerned. What I expected on this Blonde Ale was a pH that showed that I was very close and just needed a few drops of lactic acid in the mash. It was quite a bit higher than that. If that trend continues through the next 10 batches or whatever, I will assume that I have been mashing & boiling at a pH that is higher than ideal. It's always something.

[Big Nake]

More: Here's a weird one. I collected the runnings from my mash and then added my sparge water and took a pH reading (1 minute with the ColorpHast strip) and it was a little high (dark). So I added a small amount of lactic acid... probably less than ½ ml. I stirred and then took the reading again (1 minute) and pulled out the strip. It was yellow. Like 4.4 or so. WTF. My guess is that I should've waited a little longer or stirred it more or something. So I took another reading when all of my runnings were collected in the brewpot and before I started the boil. It lined up almost perfectly with 5.3 (actually 5.0 with the .3 correction factor) so I thought it looked pretty good at that point.

[zymot]

If somebody wanted to sacrifice a few strips, they can do an experiment.Submerse several strips at the same time. Pull one out after 1 second, pull the next out after 10 seconds, pull another after 30 seconds, pull the last out after 60 seconds. Compare the strips side by side. If they have different colors, we can see that time makes a difference.If they are different, we are then left figure out how to determine the optimum time of exposure.If they all produce the same reading, look at them over time and see if and how the reading(s) change over time.

[denny]

This may be helicats, but you can double the usage of ColorpHast strips by cutting them in half lengthwise.

[positiveContact]

This may be helicats, but you can double the usage of ColorpHast strips by cutting them in half lengthwise.

it is a little bit but it's always nice to post it for those that missed it.do you have to keep straight in your head what board specific terms to use? I would guess if you said helicats anywhere else people would have no idea what you are talking about.

[denny]

it is a little bit but it's always nice to post it for those that missed it.do you have to keep straight in your head what board specific terms to use? I would guess if you said helicats anywhere else people would have no idea what you are talking about.

This is pretty much the only board of all the ones I frequent that has its own lexicon...one of the reasons I love this place! I have occasionally used memes from one board on another and had them picked up there. One that I'd like to see used more frequently is "dickchimp"....got that from Rat Chat and it deserves to be everywhere!

Edited by denny, 17 January 2013 - 12:02 PM.

[Big Nake]

This is pretty much the only board of all the ones I frequent that has its own lexicon...one of the reasons I love this place! I have occasionally used memes from one board on another and had them picked up there. One that I'd like to see used more frequently is "dickchimp"....got that from Rat Chat and it deserves to be everywhere!

You got it... StudsTerkel, stop being a dickchimp!Happy now Denny?