Potassium Metabisulfite Question

[Bigtex2884]

So I have read some, probably not all, threads on PM/campden tabs being used to rid tap water of Chloramines. My question is if you add too much does the excess get boiled off or will there be residual yeast killing compounds still in the wort after the boil that would not allow fermentation after pitching the yeast and kill them?

 

[mabrungard]

Excess metabisulfite is decomposed during the boil, so you don’t need to worry for your yeast. However, you don’t want to overdose since it adds ionic content that may not benefit the beer.

 

[Bigtex2884]

Okay thanks so in beginners words. It may make it taste different than intended and the boil will neutralize any yeast killing potential by the time it makes it to the fermenter.

 

[RPh_Guy]

Excess sulfite will be removed via oxidation in the mash (or even before then). Boiling does NOT get rid of sulfite.

Also, you would need crazy high levels of sulfite to inhibit yeast at beer pH.
https://***************.com/wiki/Sulfite#Microbial_Effects_in_Beer

In other words, just use as directed and there's nothing to worry about.

 

[Bigtex2884]

So with this would I follow the to kill wild yeast or to sanitize?

 

[RPh_Guy]

So with this would I follow the to kill wild yeast or to sanitize?

You can use it as a no-rinse sanitizer. It should be used with an acid to increase efficacy. A good recipe is 1 Tbsp of the sulfite plus 1 Tbsp of citric acid in 1 gallon. This solution would only be effective for maybe 24 hours or so. However it's probably not the best option for sanitizing compared to other products.

Besides a small amount for chlorine removal or low oxygen brewing, sulfite generally isn't useful for making beer.

 

[Bigtex2884]

I only want to use it as a way to get rid of Chloramines. I added a tablespoon of it and citric acid and added it to 14 gallons of water and ended up with 12ish in my fermenter.

 

[RPh_Guy]

... You added 1 Tbsp of the sulfite and citric acid to your strike water?

To treat 14 gallons of water for chlorine you need less than half a gram of potassium metabisulfite, and no citric acid.

Chlorine removal has nothing to do with sanitation.

Sorry for any confusion. You're going to want to aerate that thoroughly to make sure all the sulfite gets oxidized.

 

[doug293cz]

I only want to use it as a way to get rid of Chloramines. I added a tablespoon of it and citric acid and added it to 14 gallons of water and ended up with 12ish in my fermenter.

A tablespoon is way too much. You only need about 200 - 225 milli grams for each 10 gal of water to neutralize chlorine/chloramine. A single Campden tablet is about 440 mg and will treat 20 gal of water. You should either use tablets, or an accurate scale for adding Kmeta.

Brew on

 

[RPh_Guy]

You only need about 300 - 350 milli grams for each 10 gal of water to neutralize chlorine/chloramine.

How'd you get those numbers?

 

[Bigtex2884]

I did shake the crap out of it one in the fermenter To oxygenate it and when I transferred it from the boil kettle to the fermenters I did a slow high transfer. I only added the acid blend to bring down the ph to around 5.6. I have pretty hard tap water like 8+.

the damage is done so to speak so what negatives am I potentially looking at. Fermentation has slowly started today and I pitched last night around 6pm.

 

[doug293cz]

How'd you get those numbers?

I edited them down a bit after double checking the contents of a Campden tab. @ajdelange went thru the derivation of this somewhere in the "Brew Science" forum.

Edit: Found the source.
Brew on

 

[RPh_Guy]

That'll generate about 200ppm of sulfate, which may throw off the mineral profile. Sulfate tends to enhance bitterness and dryness.

If there's any unoxidized sulfite when you pitch yeast, you made get a sulfurous aroma and possibly poor fermentation performance.

@doug293cz Looks better.

 

[Bigtex2884]

Well it’s a lemon shandy so I’ll let y’all k ow in about 4 weeks. OG was 1.050 so we shall see how those yeast munch.

 

[VikingBrewer]

So I’m trying to wrap my head around all this and I’m a bit confused. Doesn’t take much .

So I have a pack of the Spagnols Potasium Metabisulphite. Acquired this in a wine equipment kit I bought.

So is this used to rid your water of chlorine/chloramine or is it used for a no-rinse sanitization? Both??? I don’t get how it can be both.

I’m not a fan of using added chems so I’m reluctant to use this.

If used to rid chlorine/chloramine, what’s the process? Add to water (for how long) then boil the water before adding extract and fermetables (or all grain ingredients) or no need to boil?

 

[VikeMan]

So is this used to rid your water of chlorine/chloramine or is it used for a no-rinse sanitization? Both??? I don’t get how it can be both.

It can be used for both. When used as a sanitizer, the concentration of metabisulfite is higher than when treating water for chlorine/chloramines.

If used to rid chlorine/chloramine, what’s the process? Add to water (for how long) then boil the water before adding extract and fermetables (or all grain ingredients) or no need to boil?

You just add it to the water and dissolve. Done.

 

[VikingBrewer]

When used as a sanitizer, the concentration of metabisulfite is higher than when treating water for chlorine/chloramines

If used for Sanitation, best practice to sanitize a 23L fermenter, use 1-2 gallons or fill and add accessories inside?
How does it compare with Star San?

You just add it to the water and dissolve. Done.

What quantity per liter or gallon for sanitation vs dechlorinization?

 

[VikeMan]

How does it compare with Star San?

Star San is easy and reliable, which is why so many people use it. I can't think of any brewers I know off hand using K-Meta for sanitizing. I think a lot of winemakers do though, maybe because it also has other uses in winemaking.

What quantity per liter or gallon for sanitation vs dechlorinization?

I believe it's 2 oz per gallon of water for sanitizing. But that's going off of memory and I don't use it for sanitizer, so I'd recommend verifying. Or do what @RPh_Guy says in post #6.

 

[Vale71]

How does it compare with Star San?

StarSan is a sanitizer and is somewhat effective, metabisulphite is not and will have no effect as regards sanitation.

 

[VikeMan]

StarSan is a sanitizer and is somewhat effective, metabisulphite is not and will have no effect as regards sanitation.

If this is true, there are thousands (millions?) of winemakers fooling themselves.

 

[Vale71]

If this is true, there are thousands (millions?) of winemakers fooling themselves.

No their not, you're just mixing up sanitation of surfaces with sanitation of wine must. The question I responded to referred to sanitation of surfaces and for that a simple metabisulphite solution is about as effective as tap water.

 

[VikeMan]

No their not, you're just mixing up sanitation of surfaces with sanitation of wine must. The question I responded to referred to sanitation of surfaces and for that a simple metabisulphite solution is about as effective as tap water.

No, I'm not confused. I'm saying that many winemakers use metabisulfite for sanitizing equipment. They use it at a much higher concentration than for wine must.

 

[Vale71]

If they're doing it right they're also mixing it with an acid such as citric to lower PH below 3.0 in order to release SO2 which is indeed a sanitizer. Just filling your fermenter with a metabisulphite solution will not achieve anything and is only a waste of time and material.

 

[RPh_Guy]

If they're doing it right they're also mixing it with an acid such as citric to lower PH below 3.0 in order to release SO2 which is indeed a sanitizer. Just filling your fermenter with a metabisulphite solution will not achieve anything and is only a waste of time and material.

Do you know the pH of 2oz/gal (15g/L) potassium metabisulfite in water?

 

[VikingBrewer]

Do you know the pH of 2oz/gal (15g/L) potassium metabisulfite in water?

I just used this formula today “for sanitation” of my bottles, it’s what came up when I googled the ratio to sanitize. Usually I used a teaspoon of bleach to 4 liters and rinse thoroughly.

 

[barada83]

Extended boiling such as what is done during the boil removes chlorine and choramines from tap water. Chlorine has no impact on amylases It’s a waste to add metabisulfate to tap water prior to mash etc. if you are topping up after the boil or something then it might be more applicable. But then it’s also probably dilute. Sulfates and sulfates are used to inhibit microbial growth. Extensively in wine, smoking meat, and sausage making.
Chlorine does nothing negative to the mash I terms of amylase activity, nor does it chemically interact with anything else to form permanent compounds. I’d recommend skipping the campden prior to the boil.

 

[VikeMan]

Chlorine does nothing negative to the mash I terms of amylase activity, nor does it chemically interact with anything else to form permanent compounds. I’d recommend skipping the campden prior to the boil.

It sounds like you're saying that chlorine/chloramines in the mash will not react with phenols from the malt to form chlorophenols. Why would that be the case?

Extended boiling such as what is done during the boil removes chlorine and chloramines from tap water.

Until all of the chloramines have boiled away (if in fact they all do), what prevents them from forming chlorophenols in the boil?

 

[doug293cz]

Extended boiling such as what is done during the boil removes chlorine and choramines from tap water. Chlorine has no impact on amylases It’s a waste to add metabisulfate to tap water prior to mash etc. if you are topping up after the boil or something then it might be more applicable. But then it’s also probably dilute. Sulfates and sulfates are used to inhibit microbial growth. Extensively in wine, smoking meat, and sausage making.
Chlorine does nothing negative to the mash I terms of amylase activity, nor does it chemically interact with anything else to form permanent compounds. I’d recommend skipping the campden prior to the boil.

Do you have any references for chlorine/chloramine not reacting in the mash/boil to form chlorophenols?

Brew on

 

[barada83]

It sounds like you're saying that chlorine/chloramines in the mash will not react with phenols from the malt to form chlorophenols. Why would that be the case?

The reality is that this is pretty advanced organic chemistry. Chlorophenols are formed via specific reactions efficiently which are known. Check out this link which is the easiest to understand. :phenol | Definition, Structure, Uses, & Facts

The fact is that the mash or boil has neither the catalyst, the temp, or the supply of the raw materials to do much of anything to form chlorophenols. It is not just a magical reaction that occurs when phenols and chlorine are potentially present but is much more complex. Especially in anything less than industrial scientific situations where chlorine gas is available at 100% concentration. Note the reactions and the conditions required.

Phenols are a pretty present reality in life. Many smells are phenol based, not pure phenol but a phenolic ring forming the basis of an aromatic compound. Phenols are definitely a potential for off flavors. Phenols are present in the malt and are created through yeast during fermentation. I really really doubt that those are caused by chlorophenols for all of the above reasons. There are brewing science papers but I have not seen one that addresses the off flavor of chlorophenols due to municipal chlorination. I'd check the off flavor phenols caused by wild yeast or bad temps before running down the chlorophenol route.

Just to be clear, I'm not doubting that if you did an HPLC of the beer that you wouldn't find chlorophenols, its just that the presence would be for all practical purposes completely undetectable.





Until all of the chloramines have boiled away (if in fact they all do), what prevents them from forming chlorophenols in the boil?

Chemistry

 

[RPh_Guy]

Does boiling remove chloramine?

Edit: I see that it does.

 

[RPh_Guy]

Maybe this will help...
https://www.researchgate.net/profil..._using_SPE/links/00b49515427f3a603f000000.pdf

 

[VikeMan]

Chemistry

Oh. Alright then.

 

[Yooper]

If they're doing it right they're also mixing it with an acid such as citric to lower PH below 3.0 in order to release SO2 which is indeed a sanitizer. Just filling your fermenter with a metabisulphite solution will not achieve anything and is only a waste of time and material.

No, we're not. Using k-meta at 40 grams per gallon of water. I just gave a talk on HomebrewCon on winemaking and covered sulfite quite a bit. That ratio makes a very high concentration of SO2 (which can really make you cough!). You can mix it with citric acid, but you don't have to for sanitizing surfaces.

Brewer's use it to remove chlorine/chloramine in a tiny dose, though.

 

[barada83]

Apologies to Vikeman- my response of Chemistry was only to the second part of the reply. The first part is buried in the quote where I went into much more detail. I imagine that seems a bit harsh

Challenging some dogmas here. Here are some articles that aren’t crazy deep into the organic chemistry
https://www.lenntech.com/processes/disinfection/chemical/disinfectants-chloramines.htm
https://pubchem.ncbi.nlm.nih.gov/compound/chloramine#section=3D-Conformer
Chlorine gas rapidly comes out of water. Ammonia is added to stabilize the chlorine and creates a soluble, less reactive chemically, and more long lasting disinfectant. It is almost impossible for a home brewer to filter out. It decomposes to ammonium nitrate. That’s not a very reactive chemical to phenolic compounds in general. It’s used to donate hydrogen to quench a Grignard reaction. Not much more that I have found besides that.
The biggest culprit of homebrewing off flavors is going to be through phenol production itself instead of chlorophenols. Polyphenols are present as lignin in the malt husk, and those can be extracted during the sparge with too high of temp or wrong ph usually. Also other aromatic phenolic compounds in hops. (VOL. 116, NO. 4, 2010 369A Discussion of Polyphenols in Beer Physical and Flavour Stability)
During the fermentation, yeast produce phenols. Some is through metabolism and can be increased through increased ferrulic acid that can be optimized through specific mash conditions when phenols are created on purpose like for a good German style Hefeweizen https://www.brewingscience.com/wp-content/uploads/2019/06/Wheat_Beer_Yeast__Fermentation.pdf .

I will summarize. Chlorine gas is pretty reactive but rapidly comes out of the water when sitting and especially boiling. You can easily filter it out as well. There are not very many phenols to react with that would make it into the fermentation unless your process is off. Chloroamine is probably not something to worry about and not much you can do about it anyway besides adding more chemicals into the system. One of those is sulfur in sodium metabisulfite. Other phenolic compounds and their production by yeast during fermentation is going to likely be your issue if you are detecting phenolic defects. Not your chlorine or chloroamines.
If there are any scientific papers on the topic of ammonia chloride or chloroamine reactivity to phenolic compounds I’d be happy to see those. Not just the same oft repeated but popular resources that do little more than say it happens when the two come together in a solution. Chemistry is a bit more complicated than having the right components in the same space. It requires conditions to be right. Wood doesn’t just spontaneously combust when oxygen is present but the chemical equation might give the appearance otherwise.

 

[VikeMan]

I will summarize.

If I understand your argument, it can be summed up as something like... mash conditions are not very good for production of chlorophenols. Therefore any chlorophenols produced in the mash can't affect the flavor of the beer. Is that a fair summary?

 

[RPh_Guy]

That’s not a very reactive chemical to phenolic compounds in general.

Did you have a look at the article I linked?

 

[VikeMan]

@dmtaylor, you're a Chem-E if I recall correctly. What do you make of this (the chlorophenol part of the discussion)?

 

[dmtaylor]

Does boiling remove chloramine?

Edit: I see that it does.

Not very well, takes friggin forever and a day.

 

[dmtaylor]

@dmtaylor, you're a Chem-E if I recall correctly. What do you make of this (the chlorophenol part of the discussion)?

Yes I am... by degree but maybe not in practice. My own 2 cents:

A lot of what @barada83 says seems to make sense, he/she seems to know some stuff... but I still have points and questions which we can continue to discuss openly among all of us:

One thing I know for sure: Chlorine (Cl2 gas) is extremely reactive. I cannot see how the presence of any hypochlorite, a.k.a. "bleach", a.k.a. "chlorine" prior to mashing and boiling could NOT cause chlorophenols in the finished beer. This is to say I'm sure any standard chlorinated tap water (maybe not chloramine?) will definitely be a problem. If your water smells or tastes like a swimming pool prior to brewing with it, you're certain to have problems.

But what about chloramine? That is what I don't know so much about personally. @barada83 seems to be making an argument that chloramine is so stable that it's really not causing a problem. Is it? I'll confess I don't really know off-hand, and that I'm too lazy to look it up, but he/she may be onto something, maybe. Worth some deeper review as we find the time.

Also there is the argument that more phenol comes from the yeast itself moreso than the mash. This I believe is likely. All yeasts produce phenolic compounds, and in my own experience I know more of my witbiers and hefeweizens have had little hints of chlorophenols in my finished beers than other styles have. If I were smart, I'd start using distilled water for these styles especially, and/or maybe quit the tap water + Campden treatment for all styles at some point. I like using tap water, it's cheap and convenient, but even the usual Campden doesn't always seem to get all of it out, or at least it seems this way to me, as I'm very sensitive to chlorophenol and it drives me up the wall.

Now... Could my "chlorophenol" be some other kind of phenolic compound, not really chlorophenol? On this I have my doubts. I think we know the smell and taste of Band-Aids or Chloroseptic when we sense it. It is what it is. Get that damned hypochlorite out of your brew, via Campden or boiling or both, or better yet, use RO or distilled. It's an annoying distraction and painful to dump a batch where you find a little too much chlorophenol in the finished product, what a waste. It ain't worth the risk. I feel myself talking myself out of using tap water (my municipality uses hypochlorite) anymore. But gosh... it's just that much cheaper!

But chloramine...... is it safe to brew with? Um, I really don't know. And I don't know anyplace around here in 'Sconsin that uses it, so I have no personal experience with brews made with it.

So there's my initial thoughts. Thanks for the shout VikeMan. Cheers all.

 

[mabrungard]

This is hilarious! Why would you take advice from a source that just joined the forum, spouts information that flies in the face of dozens of textbooks and probably your own experience, and hasn't identified who they are? Does the word 'trolling' come to mind?

Chlorine compounds are very reactive and they readily react with organic compounds to form other compounds. The reaction of hypochlorite or chloramines with organic-rich wort is of great interest to brewers and they KNOW that it readily forms chlorophenols in wort and beer.

I see that Sulfite somehow popped up in this metabisulfite thread. Please be aware that while both of those molecules have sulfur and oxygen and they share the term 'sulfite', they are quite different and you can't infer the behavior of one from the other. When you add sodium or potassium METABISULFITE (S2O5) to an aqueous solution, it dissociates to bisulfite ions (HSO3). Bisulfite is thermally-unstable ion and it will decompose into sulfur dioxide (SO2) gas which leaves the boiling wort or water.

SULFITE (SO3) is a different molecule and it is much more stable and it does not readily leave an aqueous solution. The likelihood that you produce sulfite in your wort from a metabisulfite addition is low, since wort is typically acidic and that reduces the formation of sulfite and encourages bisulfite formation.