Chlorophenol SMaSH Experiment

[KiterNick]

Agree on the triangle tests...I remember in high school a project where each group had to come up with a sensory test. One group said they were going to try to investigate the effect of vision on taste, so they blindfolded us and had us drink different pop and guess what each was. They dyed 7-up green and made sure we could peek a little bit though the blindfold and almost everyone labled it as mountain dew...including me...

In case you don't know what the triangle test is, you randomly give each member 3 samples, 2 of one type and 1 of the other type. You ask them to select the one that is different. After you have the results you can apply basic statistics to determine if there was a discernable notice...

 

[dennis0]

Check out this article for tips on setting up a good taste study:
http://mindyourdecisions.com/blog/2...st-that-can-help-you-save-money/#.Uo4UVaDnYtA

 

[dysphoria]

Looking forward to the outcome of this also - that being said, I recently had a chlorophenol mystery on my hands when 2-3 batches came out with some pretty severe band-aid flavor.

I went through all sorts of different variables(AC filter change, campden, moving to a different water source, etc).. turns out, that I forgot one variable late in the game. I was making up my batch priming solution with tap water but not running it through my carbon filter or treating with campden.. doh! Felt pretty stupid to miss something so obvious, but all batches since then have been band-aid free.

Moral of the story.. priming water is not an exception

 

[FreddyMar3]

Thanks for the input everyone. I am going to shoot to do the triangle test. One week away...

 

[ballsy]

Update? How'd the testing go?!?

 

[FreddyMar3]

Sorry for the delay! I did do the blind triangle test and the results were encouraging. Unfortunately I only got to test 15 ppl (small turnout this month) but 7 of the 15 chose correctly. I definitely want to test more people as I still have a decent amount of samples left.

I will mention that the difference in taste is minute. Another member and I were reflecting in beers we have created without treating for chlorine/chloramine (back in my n00b days) and we agreed that we noticed higher levels of chlorophenols than what we thought we perceived in the test. The led us to theorize that perhaps a beer with a higher grain and, more likely, higher hop content would create more chlorphenols since there would be a higher concentration of phenols available in the wort.

I will continue to test more people and post results here.

 

[PDX_T]

Sorry for the delay! I did do the blind triangle test and the results were encouraging. Unfortunately I only got to test 15 ppl (small turnout this month) but 7 of the 15 chose correctly.

I don't have a triangle table in front of me, but is this really a significant difference? The chances of picking it at random are 1/3. 7/15 does not seem significantly different.

I can't seem to remember if you wanted a difference or not!

 

[SpeedYellow]

^^ that was my thought too... 7/15 is pretty close to random guessing.

Can the OP summarize the experiment; I can't figure it out. So you made 2 batches of the same recipe, using filtered tap water, except one of them was treated with campden and the other was not? Since it's not a split batch, there could potentially be other differences in the beer due to process variation, correct?

By the way, what's your level of (a) chlorine and (b) chloramine in your tap water?

 

[KiterNick]

There is chart here:

http://www.mikromarkt.eu/pdfs/uk_modul_9_t4.pdf

with 15 the thershold for 95% confidence is 9, so the hypothesis failed at the 95% confidence level...

 

[FreddyMar3]

Sorry it is taking so long for me to get back to this. New job and house have consumed much of my HBT time.

I couldn't do this experiment as a split batch since the ingredient I was altering is the brewing water (prior to brewing). I made two, 1.5 gallon batches of beer with 2-row and cascade. I did them simultaneously on my stove and used grain socks as a mini BIAB. I did my best to keep everything the same except that the tap water I used was treated with campden in one batch and nothing in the other batch. Neither batch of water was run through a filter of any sort.

The level of total chlorine (which is nearly all chloramine) is about 1.3 ppm.

I agree that, for this recipe of beer, it seems the campden addition didn't create a noticeable difference. I have more samples of the experiment so i am hoping to do some more testing since 15 results is not many.