Minimum chlorine levels for noticeable phenol/band aid flavours?

[stuartf]

Does anyone have any info on what levels chlorine can start to create bamd aid flavour? Im trying to determine whether i have a problem with wild yeast or chlorine in my brew water. I'm beginning to suspect (and hope) it is the chlorine as i dont have any gushing from the bottled beer and there are no other off flavours i can detect. Looking at my local water supplier's report the level of chlorine (added as Cl gas) has roughly doubled in the last year from mean value of 6 to 10 mg/l. I thought this was still a pretty low concentration but would this be enough to cause noticable band aid flavour? The last 2 beers ive made (both pilsners) have had a strong band aid flavour. For good measure I've done a good caustic clean of my fermenters and ferm fridge but really do t want to waste another beer trying to figure out where the problem is if i can avoid it.

 

[MHB]

Generally the flavour threshold is a fairly broad range, something like 3-40ppm. Some people are very sensitive to chlorophenols some less so, even when less than noticeable as a discrete flavour they can detract from the overall enjoyment of the beer at extremely low concentrations.
Been a couple of threads on getting rid of Chlorine and Chloramines, its pretty easy and well worth doing.
MArk

 

[stuartf]

Hi mark, yeah ive read all the threads i could find so pretty happy i can deal with the issue if thats whats causing it. Hadnt been able to find any info on what levels could cause issues though. From the range you suggest my Cl level could be high enough and as its roughly doubled since last year it does seem likely that i am now detecting it when i couldnt before. Thanks for the info

 

[Lyrebird_Cycles]

Generally the flavour threshold is a fairly broad range, something like 3-40ppm. Some people are very sensitive to chlorophenols some less so, even when less than noticeable as a discrete flavour they can detract from the overall enjoyment of the beer at extremely low concentrations.
Been a couple of threads on getting rid of Chlorine and Chloramines, its pretty easy and well worth doing.
MArk

The more commonly accepted lower bound for threshold of chlorophenol in beer is ten times lower than your lowest level, 300 ng/l = 0.3 ppb, see for instance. http://www.aroxa.com/beer/beer-flavour-standard/2-6-dichlorophenol/

It is reasonably commonplace to have a 100 fold difference in threshold between the first and ninth decile of population.

 

[Jack of all biers]

Does anyone have any info on what levels chlorine can start to create bamd aid flavour? Im trying to determine whether i have a problem with wild yeast or chlorine in my brew water. I'm beginning to suspect (and hope) it is the chlorine as i dont have any gushing from the bottled beer and there are no other off flavours i can detect. Looking at my local water supplier's report the level of chlorine (added as Cl gas) has roughly doubled in the last year from mean value of 6 to 10 mg/l. I thought this was still a pretty low concentration but would this be enough to cause noticable band aid flavour? The last 2 beers ive made (both pilsners) have had a strong band aid flavour. For good measure I've done a good caustic clean of my fermenters and ferm fridge but really do t want to waste another beer trying to figure out where the problem is if i can avoid it.

Sorry I'm late on the uptake on this thread. Are you sure your water report is 6-10 mg/L of free chlorine residual and not 0.6-1 mg/L. The NHMRC health guidelines puts the upper limit of 5 mg/L. If it is you should report your local water supplier. Also if it is that high then the chlorophenols will kick you in the face, so that may be why your brews have suddenly began to have that band aid flavour. I feel for you. My local water ranges from 2 mg/L to 0.1 mg/L with the average of 0.3 mg/L and I can sometimes detect a slight flavour if I don't treat it.

 

[BKBrews]

I bought a grainfather and have done two tippable bathes to kick things off, which I've pretty much put down to chlorophenols from dodgey water. One was an IPA that is REAL bad and the other is a SMaSH that is bordering on drinkable.

I brewed on Saturday, with the plan to 100% determine whether the water is my issue. So I've done another Maris Otter SMaSH, just using a slightly different hop schedule as I didn't have the same hops on hand. I filled the grainfather to the brim (31 - 32L) the night before, chucked in a vitamin C tablet and then boiled it for 2 or so hours (I actually planned on just boiling for say half an hour but I went out after filling it and didn't realise that I'd left it on!). When I got home I topped it up to 31 - 32L while still hot (as some boiled off), put the lid on and left it until the next morning. When I was ready to brew I just put took water out and put it into my sparge vessel until I had my mash water amount in the GF and chucked in a tablespoon of Gypsum for good measure. This actually worked out really well because my water was already at about 45 - 50 degrees when I was ready to brew!

The SG wort definitely tastes sweeter and smoother than my previous batches (albeit a slightly lower IBU) and I actually think the fermentation looks cleaner as well. It kicked off after about 18 hours (re-hydrated dry yeast) and the krausen was a silky looking foam that slowly rose evenly. I could just be willing it to be better, but all signs so far point to a better brew. I will take a hydro reading next Saturday to see where we're at and I can't wait to taste it!

EDIT: I should also add that my first two batches were filled from the garden hose and stupid me forgot to run a few litres of water through it first and dump it - straight into the GF it went - which will have to have contributed to my off flavours. This time the GF was filled directly from the tap.

 

[Jack of all biers]

Your Ascorbic Acid treatment and the 2 hour boil would have gotten rid of a huge proportion of residual chlorine so I would be surprise if it didn't taste better. I have always had better brews with a simple boil of the mains water before hand. Here's hoping it turns out a cracker for you. :chug:

 

[Lyrebird_Cycles]

I filled the grainfather to the brim (31 - 32L) the night before, chucked in a vitamin C tablet and then boiled it for 2 or so hours (I actually planned on just boiling for say half an hour but I went out after filling it and didn't realise that I'd left it on!). When I got home I topped it up to 31 - 32L while still hot (as some boiled off), put the lid on and left it until the next morning.

I would recommend that you add the ascorbate after boiling the water, not before. Ascorbate is moderately heat labile.

 

[Jack of all biers]

I would recommend that you add the ascorbate after boiling the water, not before. Ascorbate is moderately heat labile.

plus one to above. Although if you add it before and give it a couple of hours before boiling it would also be ok, as I don't believe the reaction time for ascorbic acid is too long. The benefit of boiling after is that you denature any residual Ascorbic acid prior to adding it to the mash.

 

[good4whatAlesU]

Does anyone have any info on what levels chlorine can start to create bamd aid flavour? Im trying to determine whether i have a problem with wild yeast or chlorine in my brew water. I'm beginning to suspect (and hope) it is the chlorine as i dont have any gushing from the bottled beer and there are no other off flavours i can detect. Looking at my local water supplier's report the level of chlorine (added as Cl gas) has roughly doubled in the last year from mean value of 6 to 10 mg/l. I thought this was still a pretty low concentration but would this be enough to cause noticable band aid flavour? The last 2 beers ive made (both pilsners) have had a strong band aid flavour. For good measure I've done a good caustic clean of my fermenters and ferm fridge but really do t want to waste another beer trying to figure out where the problem is if i can avoid it.

We've got you covered there, 13 mg/L up in Ballina (13ppm). Currently in the process of reading existing threads to ameliorate this problem.

 

[Lyrebird_Cycles]

The benefit of boiling after is that you denature any residual Ascorbic acid prior to adding it to the mash.

Yes, but....

If ascobate residues are going to be a problem, it's the denatured resultant of breakdown (dehydroascorbic acid) that will cause the problem.

 

[BKBrews]

I would recommend that you add the ascorbate after boiling the water, not before. Ascorbate is moderately heat labile.

Thanks for that. Considering I chucked the vit c tablet in prior to the boil, what issues could I potentially encounter? Keeping in mind, once the boil was switched off (around 9pm), it sat there until 11am the next day when I commenced the mash in.

 

[Jack of all biers]

Thanks for pointing that out. From my understanding after researching this, that this would be the case though no matter when the ascorbic acid is denatured right? So boiling/heating it before or after would still result in dehydroascorbic acid (DHA) ending up in the mash, then the wort and in the final beer. This would then lead to the potential for DHA to create Hydrogen peroxide that would then release oxygen therefore oxidizing the beer. I got that from this book (page 236).

https://books.google.com.au/books?id=0os_gIvG_ccC&pg=PA236&lpg=PA236&dq=problems+with+dehydroascorbic+acid+in+beer&source=bl&ots=W3yMmYWZoq&sig=g1ke-6GWwnMl2ERVqNiC2ZC5rN8&hl=en&sa=X&ved=0ahUKEwinpbu07oTQAhWEGpQKHfQ7CdYQ6AEIGzAA#v=onepage&q=problems%20with%20dehydroascorbic%20acid%20in%20beer&f=false

So it may not be such a brilliant idea using Ascorbic acid to remove chlorine at all?

 

[BKBrews]

Tell me it isn't so. My confidence can't take a 3rd failed brew in a row.

EDIT: Is there not a chance that the created oxygen would be taken up by the yeast?

 

[Lyrebird_Cycles]

Thanks for that. Considering I chucked the vit c tablet in prior to the boil, what issues could I potentially encounter?

Simply that you are relying on residual heat to drive off the chlorine in the make up water, whereas if you add the ascorbic after boiling it will mop up any remaining chlorine.

Thanks for pointing that out. From my understanding after researching this, that this would be the case though no matter when the ascorbic acid is denatured right?

Yes, but in practice DHAA does not appear to be a problem when small amounts of it are present in the water used for brewing.

I presume* that this is because it reacts with the organics present in the boil and has no discernable effect. I use about 15 mg/l ascorbic acid to treat Melbourne water after having a couple of brews that had a faint edge of an aroma that could have been a chlorophenol. IMO the beers made after I started adding the ascorbate are better than those made before. My son, who seems to share my ridiculous level of sensitivity** to phenols of all kinds, agrees


*Caveat: I have not done enough research to find any support for, or evidence against, this idea.

** I once spent a day scanning wine samples from an export load of casks that had been rejected for phenol taints. Several (Swedish) customers had complained but none of the wnemakers from the company involved could detect the problem. It turned out to be a rare halophenol that had diffused into the packaged wine from the floor of the container.

Weirdly, I could by tell by blind tasting which level each sample was from. The cue I used was how much they reminded me of my first wife when she came home from operating theatre.

 

[BKBrews]

Simply that you are relying on residual heat to drive off the chlorine in the make up water, whereas if you add the ascorbic after boiling it will mop up any remaining chlorine.


Yes, but in practice DHAA does not appear to be a problem when small amounts of it are present in the water used for brewing.

I presume* that this is because it reacts with the organics present in the boil and has no discernable effect.



*Caveat: I have not done enough research to find any support for, or evidence against, this idea.

OK cool. So realistically when should I put it in? The water was still at about 45-50 degrees over 12 hours later (sitting in the GF with the lid on). And do I need to be careful about how much I use? I put a full 500mg vit c tablet in.

 

[Lyrebird_Cycles]

A 500 mg tablet for 30 odd litres of water is very similar to the levels I'm using (I said 15 mg/l above, it's actually around 20).

I add mine with the water amelioration salts, all the evidence is that the reaction between chlorine / chloramines and ascorbate is very fast.

 

[BKBrews]

Another quick question - do I really need to be careful with the water I use to make my sanitising solution as well? I use a phosphoric acid no rinse sanitiser from national homebrew - is this likely to neutralise any of the chlorine present? Do I even need to really worry considering it will mainly only be used to rinse kegs and bottles post fermentation? I sanitised my fermenter using the water I had boiled and added ascorbic acid too, so not worried about pre-fermentation here.

 

[Lyrebird_Cycles]

In order:

I don't think so.

No.

I don't think so.

 

[Jack of all biers]

No. No need to worry as there would only be miniscule amounts of chlorine in the sanitizer solution and if there is residual amounts of sanitizer on your fermenter/equipment when it contacts your brew then it would be the residual of miniscule.... If your really worried about it you could take your sanitizer water from your de-chlorinated brew water.