Possible Chlorine/Chloramine related issue

So we are 5 batches in on this whole thing and the first 2 batches were fantastic. Definitely some things I would have adjusted technique-wise but flavour was there. Had a ferm temp issue with the 2nd batch that caused an off flavour but it had all but dissipated with some time in bottle.

Since the 2nd batch we have switched to RO water exclusively. On the first 2 batches we used a mix of RO and tap water and treated with campden tablets. The past 3 batches have all had a very distinct off flavour. I asked someone else and he couldn't point it out. On the 4th batch, it ruined my lager completely. The last batch was an IPA and the hops cover it up on the nose, but as soon as you drink it and belch (I know, gross, sorry) the off flavour fills your mouth and nostrils. It's chemical-y for sure, however I haven't been able to pin it down.....until now.

I believe it's possibly related to chlorine or chloramine. The only difference with the last 3 is that we haven't treated with campden. Is it possible that the tap water we use for cleaning our equipment is leaving residual chlorine/chloramine on the equipment and invading the batch? If so, how do people clean their FV's? I'm really frustrated because I had to dump the lager batch because it was so pervasive and if it sticks around in the IPA I'll have to likely dump that too, though it's better than the lager for certain. What are the other possible sources of this?

Ferm temps are controlled, so I know it's not that either.

Do you produce your own RO Water or buy it from the store? If the former do you have a chlorine filter stage? Usually the store bought RO is good, but this also depends on how used the filtration system is and how frequently the change the filters.

Even if heavily chlorinated I doubt residual chlorine/chloramine from rinse water will produce the adverse affects you are experiencing. If your tap water is that chlorinated you would smell it and you would likely have very dry skin.

What are you using to clean your equipment? Are you using the cleaning agents in the recommended dilutions and rinsing thoroughly with hot water? If using bleach, be careful of the solution being used. There are many links on HBT on proper bleach solutions.

Fermentation temp control is also important. I had one bad experience (Band-aid aroma and flavor) that I determined was caused by a combination of chloramine and a very vigorous early fermentation. I now start my fermentation on the low end of the temp range and ramp up. I also used campden in by brews before installed a 4-Stage RO.

While products like Star-San produce no off flavors if used correctly, make sure there is not a puddle of liquid at the bottom before adding wort. Some feel products like Star-san affect head retention. If your beers lack head retention perhaps is too much sanitizer.

My recommendations is to review your process and products used. Try a different source for RO water or add a Chlorine stage to your set up. You can also simply fill your tuns the day before with the RO water. Leave the lids off and any chlorine or chloramine should dissipate overnight. There is also still no harm in continuing to use campden until you find a reliable source of chlorine free water. At the very least it will help you to troubleshoot the cause of the off flavor for the next couple of brews.

Good luck.

There are so many types of off flavors, so I wouldn't get stuck on chlorine/chloramine. I don't think that tap water used for your sanitization would affect a beer that much. Can you describe the flavor/smell any further? RO shouldn't need Campden, but it does need slats/minerals/etc. I haven't ventured there, but others here will recommend reading the Bru'n webpage. I think the water chemistry might be the trickiest part of home brewing, before any grains, hops or yeast even enter the picture.

I clean my conicals and kegs with regular tap water, PBW and star San. I've never had an off flavor from the small amount of chlorine in the cleaning water.

I use RO water with salt/ mineral additions based on style and grain bill. Are you sure your water is treated with chloramine? it's not supper common in the winter time In cold regions. Regardless with the slow rate of filtration in a RO set up the activated charcoal filter will remove chlorine. They sell chloramine specific filter at buckeye hydro ( I use them) and I have not had any issues. Prior to that I just used Chicago tap water with campden tablets and never had an issue.

What is the taste of the off flavor? Chlorine will combine with malt phenols to create chlorophenols. They have a medicinal taste according to White and Jamil.

As mentioned above where are you getting your RO from?
What are you using to ferment in and how are you controlling temps?
How are you adjusting ph with the RO water?
Are you reusing yeast?
Are you making starters?

I suspect it's something else in your process flow but its really hard to speculate without a good description of the off flavor.

Dcpcooks said:

I clean my conicals and kegs with regular tap water, PBW and star San. I've never had an off flavor from the small amount of chlorine in the cleaning water.

I use RO water with salt/ mineral additions based on style and grain bill. Are you sure your water is treated with chloramine? it's not supper common in the winter time In cold regions. Regardless with the slow rate of filtration in a RO set up the activated charcoal filter will remove chlorine. They sell chloramine specific filter at buckeye hydro ( I use them) and I have not had any issues. Prior to that I just used Chicago tap water with campden tablets and never had an issue.

What is the taste of the off flavor? Chlorine will combine with malt phenols to create chlorophenols. They have a medicinal taste according to White and Jamil.

As mentioned above where are you getting your RO from?
What are you using to ferment in and how are you controlling temps?
How are you adjusting ph with the RO water?
Are you reusing yeast?
Are you making starters?

I suspect it's something else in your process flow but its really hard to speculate without a good description of the off flavor.

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Thanks for all the responses.

The RO is purchased from a store, though they don't list the TDS.

I am fermenting in glass carboys controlled with a swamp cooler with the water level up to the wort level. It is monitored via a very accurate thermometer and adjusted with ice on a twice-a-day basis to hold temperatures.

The RO water is being adjusted with salts (predominantly Calcium Chloride, Epsom Salts and Gypsum) and the pH controlled with acid malt.

Yeast in first RO only batch was rehydrated S04 (2 packs), 2nd was rehydrated 34/70 (2 packs) and 3rd was rehydrated US-05.

Cleaning regimen is the same - Oxyclean Free, rinse two to three times, StarSan. All measured based on required amounts.

The off-flavour (if chloramines is certainly medicinal) is somewhere between solvent (acetone) and plastic/rubbery. That would remove the chloramine theory.

IF that is the case, then I would say that the only difference between those 3 and the first 2 was liquid yeast vs dry yeast re-hydration. I use carbon filtered tap water, microwaved and slightly cooled to re-hydrate the yeast.

I see two possibilities. Possible infection somewhere (the flavor was not there in the first batches, came on later) or your mineral adjustments (a change you made to your process.) What were the amount of mineral adjustments? I'm sure some brighter minds than mine could give you feed back on those.

Would band-aid describe it? If so that could be a phenolic flavor? Hefe, Belgian
And Brett yeasts most commonly display those flavors.
is it possible you have Brett in the house?
Does the yeast have trouble flocculating?


it sounds like your on point with water additions. Have you reviewed the water primer in the brew science section? I use anywhere between 0- 1.5-3% acid malt and just a few grams of those same salts per batch if any.

You can try a different water for a batch just to rule that out.

You have the same flavor in three different yeast. I don't see anything wrong with how your rehydrating. So I think you can step back from the yeast for now and see where else the flavor is coming from.

What about your bottling bucket, siphon hose or racking arm? Give this all a good overnight soak in oxy. Or change them out if you can.

Are you bottling or kegging? Again a good overnight soak might be in order. I have read that oxiclean in hard water can precipitate a compound that will bond with the containers. It think it's a form of beer stone which can offer a place for wild yeasts to hide. I doubt that is the case here but maybe you got some used old equipment?

A drawback to the swamp cooler set up is as the fermentation slows the temp of the fermenting beers temp can fall. Is it possible that your temp is falling at the end of fermentation and the yeast can't finish cleaning up after itself?

You can also take your beer to a brewery, club or look up a bjcp judge for feed back. You can also order an off flavors kit to see what they all taste like.

If I had to guess it's either fermentation temps or a wild yeast or bacteria getting in somewhere.

Thanks so much! I am careful to take my fermenters out of the swamp cooler once fermentation has slowed down and free ride to room temp which may not be high enough now that I think about it. However I may be leaning towards the bottling bucket. That's a distinct possibility. The beer doesn't really have that smell in the fermenter but once I add to bottling bucket, the smell is there. Hard to say. I will see if I can give a bottle to a brewer friend for further feedback on the specific off flavour.

BrewKaiser said:

My recommendations is to review your process and products used. Try a different source for RO water or add a Chlorine stage to your set up. You can also simply fill your tuns the day before with the RO water.

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Nearly all the residential RO systems on the market these days use what is called a TFC (thin film composite) style of RO membrane. Chlorine will ruin a TFC membrane, so these systems use a carbon prefilter. Carbon treats the chlorine.

Carbon will also address chloramine, but if your tapwater contains chloramines it's good practice to add a second carbon prefilter, and use a high quality, very fast acting type of carbon for one or both of the carbon stages - this is what Dcpcooks is referring to above.

Leave the lids off and any chlorine or chloramine should dissipate overnight.

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Chlorine will volatilize, especially if the water is aerated, but chloramine will not volatilize. That's one of the reasons a water utility may elect to use chloramine rather than plain ole' chlorine.

Bottom line: treat chlorine or chloramines before it reaches the RO membrane.