Minimum chlorine levels for noticeable phenol/band aid flavours?

[BKBrews]

In order:

I don't think so.

No.

I don't think so.

Thanks - didn't think so. I'm learning - I'd guess I don't need to worry because the chlorophenols are produced by the active yeast and not post ferm....

 

[BKBrews]

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.

Been doing that for my pre-fermentation sanitiser solution - was really only concerned about post fermentation when I've used all of that de-chlorinated brew water weeks prior. All good though, didn't think it would be an issue and sounds like it isn't Just paranoid now!

 

[MHB]

Thanks - didn't think so. I'm learning - I'd guess I don't need to worry because the chlorophenols are produced by the active yeast and not post ferm....

I would be very worried about that assumption, the Phenols that are getting Chlorinated are mostly extracted from the husks.
Note the s on the end of the phenols - there are lots of different phenols, tannins, polyphenols flavonoids... that are mostly extracted during mashing. Some also come from hops many of these are alcohols (have an -OH group) and can be halogenated.

Treat your water before mashing in, I would choose Metabisulphite over Vitamin C, I think it is going to be a much better and faster scavenger of Cl and am much less concerned about the effects of its breakdown products and the effect of any left over.
Mark

 

[Lyrebird_Cycles]

Mark, do you have any references for polyphenols being involved in chlorination reactions in wort or beer leading to flavour active compounds?

 

[Jack of all biers]

BK, have a look at this site for a few tips and tricks. It's not the be all and end all, but you could do a lot less researched than Martin's knowledge on the matter. https://sites.google.com/site/brunwater/water-knowledge I've read elsewhere the 1mg/L dosage rate for chloramine levels of 1 mg/L and Martin advocates 1.7 mg/L to remove up to 3 mg/L chloramine. This is well below your 500mg tablet dosage or what Lyrebird uses. This is probably why I was of the belief that adding it before the boil or after wouldn't matter, because I add 1 mg/L (my highest residual chlorine level is less than 2 mg/L).

"Ascorbic Acid (Vitamin C) addition is effective for chlorine and chloramine removal. As indicated in the compound's name, this is an acid and it does reduce water pH if unreacted with a chlorine compound. In distilled water, it can produce a pH as low as 3.0. It is sometimes used in municipal water treatment, however it's pH reduction effect and higher cost can make it less desirable than metabisulfite addition. Ascorbic acid is added at a rate of 1.7 milligrams per liter (~6.4 milligrams per gallon) to remove up to 3 milligrams per liter of chloramine. The reaction equation for ascorbic acid and chloramine produces ammonium (NH4), chloride, and dehydroascorbic acid. Since the dosing is very low, the resulting concentrations are not a concern. Be aware that ammonium is a yeast nutrient and is not a problem in brewing water. The reaction is shown below:
ascorbic acid (C6H8O6) + monochloramine (NH2Cl) --> NH4+ + Cl- + C6H6O6
A similar dosage will also remove chlorine (OCl-) from water. The reaction produces water, chloride, and dehydroascorbic acid.
ascorbic acid (C6H8O6) + hypochlorite (OCl-) --> H2O + Cl- + C6H6O6"

 

[Lyrebird_Cycles]

Ascorbic acid MW = 176 g/mol, NH2Cl MW = 51 g/mol, stoichiometry as stated is 1: 1, therefore 176 / 51 ~ 3.5 mg/l ascorbic reacts with 1 mg /l of chloramine.

It looks to me like someone has made an arithmetical error in your reference, 1.7 mg/l ascorbic would be the required addition rate for 0.5 mg/l chloramine, not 3 mg/l.

Perhaps Martin can comment.

 

[BKBrews]

Haven't read anything there that alarms me. Will see how this batch turns out anyway. 5 days in and it definitely has a more persistent Krause than I have previously had with us-05, so interesting to read about the ammonium.

Ps the tabs I have are 300mg ascorbic acid and 227mg sodium ascorbate.

 

[Lyrebird_Cycles]

300mg ascorbic + 227 mg sodium ascorbate is equivalent to 500 mg ascorbic, it will just have a higher pH when dissolved.

XXX-ic acids become XXX-ate anions when dissolved, XXX-ous acids become XXX-ite anions etc.

 

[Jack of all biers]

Mark, do you have any references for polyphenols being involved in chlorination reactions in wort or beer leading to flavour active compounds?

The Bru'n water site I linked above states that chlorine can turn into hypochlorite which bond with 'organic compounds in the wort' to form chlorophenols. Also Palmer states that chlorine compounds can combine with phenols to form chlorophenol. Interestingly though the Complete Beer Fault (Thomas Barnes) guide states that the chlorine compounds react with alcohol to form chlorophenols. Not sure who is right, but page 85 of this book https://books.google.com.au/booksid=mBnKIRVt4JIC&pg=PA91&lpg=PA91&dq=formation+of+chlorophenol&source=bl&ots=SiTm3CZk2u&sig=T6Xm71IwTV4wf_w2GaZdLrwYngI&hl=en&sa=X&ved=0ahUKEwiJ8ffQ6onQAhUHi5QKHeOTC_cQ6AEITzAG#v=onepage&q=formation%20of%20chlorophenol&f=false suggests that chlorine bonds with phenols to form the taste and odor forming chlorophenols. Also page 495 of this book https://books.google.com.au/books?id=0os_gIvG_ccC&pg=PA495&lpg=PA495&dq=formation+of+chlorophenol+in+beer&source=bl&ots=W3yNd3X_rn&sig=NdcenslsCGMciVGrgBJmQCwe4xo&hl=en&sa=X&ved=0ahUKEwj4qbX064nQAhVDOJQKHU1mBWsQ6AEIbjAQ#v=onepage&q=formation%20of%20chlorophenol%20in%20beer&f=false suggests "selective absorbtion of polyphenols from beer reacted with chlorinated detergents to form chlorophenols" although it sites a study that reports using chlorine dioxide does not form chlorophenols when in contact with beer (when used to sanitize equipment of brewery sized equipment) . Of that fact I am skeptical.

EDIT - I can't get that second link to go on as a link sorry. Tried multiple times, but it will have to be copy and pasted.

View attachment Complete_Beer_Fault_Guide.pdf

 

[Lyrebird_Cycles]

I'm asking about polyphenols, not phenols. The formation pathway from phenols is well understood but I can find nothing on formation from polyphenols; I've checked through Priest, Kunze and Briggs, no mentions in any of them I can find. I was hoping Mark had a literature reference.

BTW the thing about ClO2 is quite believable. It's widely used in pulp bleaching specifically to avoid forming organochlorides from chlorine bleaching.

 

[Jack of all biers]

Yes and if you read my post again you will find one of the books I quoted states polyphenols as opposed to phenols. I am pointing out that out of a range of sources there seems to be different versions of the origins of chlorophenols in beer.

 

[Lyrebird_Cycles]

I read your post, most of it concerned phenols not polyphenols, so it seemed to me that you had not understood mine. My apologies if this was incorrect.

BTW the googbooks reference is unavailable, that seems to be their intent.

 

[Matplat]

I just bought one of these to deal with any potential chlorine issues.

Seems simpler than worrying about pre-boiling, or other additions to remove chlorine.

I have been using sodium metabisulphite up until now, but without having confirmed chlorine levels in the water, it's always a bit of a guess as to how much is required.

 

[altone]

I just bought one of these to deal with any potential chlorine issues.

Seems simpler than worrying about pre-boiling, or other additions to remove chlorine.

I have been using sodium metabisulphite up until now, but without having confirmed chlorine levels in the water, it's always a bit of a guess as to how much is required.

These work nicely so long as you maintain a slow flow and replace well before the suggested lifespan.
They work to remove chlorine and chloramine.

I always draw my water the day before a brew to allow most of the chlorine to disperse - works quite well
My local water is only chlorine treated.
If your local water board use chloramine this will not work and you need to either filter or treat your water to remove/neutralise it.

I keep tropical fish and have also in the past used their "water ager" to remove chloramine.
I think the active ingredient is sodium thiosulphate and I only use a few drops.

Hopefully the chemists here will let us all know if this is bad or good.
I assumed if the very fragile fish can handle it then I can too.

 

[MHB]

Mark, do you have any references for polyphenols being involved in chlorination reactions in wort or beer leading to flavour active compounds?

Doing a course this week and next, 10 hours per day and am just home.
Had a bit of a quick look, in short every commercial reference I could find only talks about "Chlorophenols" as a group whether mono or poly cyclic phenols. There are just so many possible ways to combine Cl and Phenols and they all suck - they are avoided as a class.

Fix, Malting and Brewing Science and even the BJCP ascribe the formation of chlorophenols to reactions between Cl and Phenols (which have an alcohol group) The consensus appears to be that these reactions happen very easily and at "mild conditions" and that the remedial steps are to:
1/ remove Cl before it enters the wort stream i.e. before you mash in
2/ minimise the available phenols by proper milling, not over sparging, proper water chemistry... all the usual suspects.

Basically no professional brewer would ever try to make beer with chlorinated water, whether you use carbon filters, RoMo, Metabisulphite, Ascorbic Acid (not the best choice on its own, perhaps) or any of many options - getting rid of the Cl is a good idea.
Mark

 

[Lyrebird_Cycles]

My question arose because phenols are unusually active WRT electrophilic substitution due to the electronegativity of the hydroxyl disturbing the aromatic stabilisation of the benzene ring to which it is appended. None of the common flavonoids (aka polyphenols) in beer have a hydroxyl group attached to an aromatic ring, so they are not as reactive. I was surprised to see your inclusion of polyphenols as I have not seen any reference to chlorinated polyphenols in the literature, I thought you might have a reference.

The (minimal) research I have done indicates that flavonoids are quite resistant to chlorination.

 

[Kev R]

With the life of carbon filters is time a factor in their effective life,or only the volume of water run through them?

Kev

 

[good4whatAlesU]

Both the volume and the quality of water run through (amount of contaminants).

 

[BKBrews]

Considering sodium metabisulphite is used as a sanitiser, I'm assuming you really don't want to use too much? What would be the recommended amount to use in ~32L of water? It's less than $10 per kg at my LHBS.

Do you assume there's up to 5mg/L and use an amount based on this?

 

[Lyrebird_Cycles]

I proceed on the assumption that a slight excess of SO2 (or in my case ascorbic) will do far less harm than underdosing, so I add enough to neutralise 6 mg/l.

With SO2 the reaction product is sulphate anion, this will raise the sulphate level by about 10 ppm. If your water chemistry is precise enough for this to make a difference you should take it into account.

As stated previously, I don't believe the breakdown product from ascorbic addition (DHAA) survives the boil but I am all ears if anyone has a reference that shows otherwise*

I own both a reverse osmosis machine and a full commercial spec carbon filter and haven't bothered using either for brewing at small scale. My problem with using either is that I don't brew enough to justify using it full time so it would need to be broken down and the cartridge stored until next time.





* Reference means a literature reference, not Palmer or a home brewer's website.