Chlorine Removal - Time Versus Temp?

[1974Alby]

Chlorine removal by aeration at various temperatures was not effective. Free chlorine
concentrations in sample #3 (S3) slightly decreased from 1.66 to 1.41 mg/L in open bottle
on a dark shelf (26C) and from 1.67 to 1.43 mg/L in open bottle in a refrigerator (5C)
for 3 days. Also, for chlorine removal in water by freezing (-20C) and melting (5C),
free chlorine concentration slightly decreased from 1.68 to 1.56 mg/L in open bottle for 3
days. In an additional analysis after 1 month, however, almost the same concentration of
free chlorine as that shown on the third day was detected (1.35 mg/L in open bottle on a
dark shelf), which indicates the long residual effect of chlorine.​

this doesnt seem to reconcile with common advice in relation to chlorine in aquarium water...standard practice (other than de-chlorination with chemicals) is to let tap water stand for 48 hours to de-chlorinate it prior to introducing fish ...the results above suggest this does bugger all. I wonder if the fish know this?

 

[manticle]

Some of the above tests were done at 5 deg C ad the highest (if I read correctly) were done at 26.. The graph MHB posted earlier suggests around 20 is where chlorine will start to come out of solution so that may explain the supposed discrepancy.

 

[Steve@PMF82]

Its like going to a hydrotherapy pool or a spa water can be around 30 - 32degrees, you can smell the chlorine gassing off, it upsets my partners asthma so that she cant even enter the establishment.

 

[szopen]

Its like going to a hydrotherapy pool or a spa water can be around 30 - 32degrees, you can smell the chlorine gassing off, it upsets my partners asthma so that she cant even enter the establishment.

In pools/spas there is a chlorination system that keeps adding (in may possible ways) chlorine when the free available chlorine level drops below set point (3-5ppm from memory).

This is different from a container of tap water that had much lower level of FAC to start with (0.5ppm) and keeps losing free chlorine with time passing and temperature raising.

 

[manticle]

Just ressurecting this so I don't pollute another thread.

Feldon - if you read this, do you know of any other papers looking at removing chlorine at different temperatures (so along the lines of the graph posted earlier? The paper you posted has bottles at a max of 26 degrees showing very little dissolution - curious about other vessels and temp stages.

Main reason i'm trying to find out is so I know whether I need to edit the info in to the article I wrote on water chem.

I'll check the databases I have access to as well.

 

[Feldon]

Just ressurecting this so I don't pollute another thread.

Feldon - if you read this, do you know of any other papers looking at removing chlorine at different temperatures (so along the lines of the graph posted earlier? The paper you posted has bottles at a max of 26 degrees showing very little dissolution - curious about other vessels and temp stages.

Main reason i'm trying to find out is so I know whether I need to edit the info in to the article I wrote on water chem.

I'll check the databases I have access to as well.

That's the only one I found, Manticle. When I get a moment I'll have a quick trawl and see if there are others available on the internet. I recall a lot of the research papers I found were more interested in keeping the chlorine in the water rather than getting it out.

Reason I was looking it up at the time was that I've long had a suspicion that residual chlorine is a main contributor to homebrew twang in kit beer. From time to time a thread comes up here about the dreaded twang and the debate starts up again. The usual causes claimed are poorly made/stored malt extract, inferior supplied kit yeast, high ferm temps etc - but never a definitive consensus on the cause, but an almost universal cry of "go All Grain" and you'll never suffer the twang again).

Then there have been posters who claim they never get the kit twang in their beers (and are promptly flamed as a result for having lousy beer palates). But it got me thinking. I'd read that chlorine can react with hop oils to produce an off 'medicinal' flavour to beer. It occurred to me that a main difference between kit brewers and all grain brewers is that the former add tap water to hopped extract to produce their wort for fermentation. All grain brewers on the other hand have already boiled the water component of their wort in the kettle (which removes residual chlorine) before any hops are added. So bingo, no twang.

 

[manticle]

Interesting hypothesis but have you ever tasted medicinal chlorephenol flavour from residual chlorine in brewing? I have and find it very distinctive and different from my experience of 'kit twang' - both when I brewed kits and when I have tried others kit beers.

Nonetheless it might be worth some kind of experiment. Levels of chlorine might also be a factor and the one brew that had band aid from unrinsed bleach in the cube (an AG brew) might have had elevated levels.

 

[Feldon]

No I haven't. But if you have access to it maybe try mixing some with me beer and see if the complex reminds you of kit twang (just don't go poisoning yourself I the process!). Be interested to know.
Its just a speculation that residual chlorine is the culprit. But I haven't heard any definitive cause for the twang. Lots of ideas though. So many variables (extract, yeast, temp etc) that I went hunting for constants. The different treatment of the brewing water (kits vs all grain) combined with the different waters brewers use at different localities (and at different times of year per locality) raised my suspicion that chlorinated water was the constant. Not enough evidence to convict, but would be good to apprehend the bugger. Home brew twang remains one of the mysteries of the craft, although I also suspect that the big kit makers would know a lot about it, but keep mum for commercial reasons.