Campden Tablets (Sulfites) and Brewing Water

I suppose one might argue that the sulfite they produce could be allergenic to those sensitive to it but most of it will be oxidized to sulfate and yeasts, especially lager yeasts, produce plenty of sulfite as any one who has fermented them in an enclosed space knows. If you have been advised to avoid lager beers but that ales are OK then perhaps you might want to avoid using campden tablets.

I run my water through a small single stage filter. Works good enough, but it's a really slow process. Typically a half hour or more. My question is, would it be best to add Campden when I start drawing the water or wait until it's all in the kettle? Or is there no difference?

I've always added it at the start, but question if it continues to be effective throughout the long filling process.

Shouldn't be any difference but you will need to keep stirring to mix the incoming water with the metabite. Based on that it is probably easier to add the metabite after the whole volume is drawn so you only have to stir once.

Are all campden tablets created equally? I bought some Crosby & Baker tablets that state they result in 30 ppm of SO2 in 1 gallon of water. From what I've been able to research, most "20 gallons treated" are estimated using campden tablets resulting in 65-75 ppm of SO2.

Can anyone offer any insight on how much of these Crosby & Baker campden tablets I should be using?

'20 gallons treated' depends on the assumption that the water contains 3 mg/L free chlorine equivalent chloramine, the campden tablet contains 625 mg and no fllers that the composition is pure potassium metabisulfite as opposed to sodium metabisulfite and that each millimole of bisulfite will reduce 2 mmol of chloramine. If any of those assumptions are changed then the dose needs to be adjusted. The first thing you need to do is find out what the tablets weigh, then determine whether they are sodium or potassium metabite and finally determine how much chlorine and chloramine are in your water. The requirements are listed in the Table in #1. The explanation from Crosby and Baker doesn't make any sense to me but I expect the conclusion is right. Given that their tablets are apparently the potassium salt and that they can't deviate too much in weight from the ones I measured years a ago and that your total free and bound chlorine is probably less than 3 mg/L 1 tablet in 20 gal should do. If that does eliminates the chlorine (smell or get a test kit) then who cares about free sulfur dioxide equivalent.

For details see http://www.wetnewf.org/pdfs/Brewing_articles/BT_Chlorine.pdf. Go straight to p 23.

AnOldUR said:

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Muchas gracias sir! I looked for hours for a simple answer and came up empty.

I brew with extract using top-off water. I put 1/3 of a tablet in the 2-1/2 gallons of boil water and then top off with untreated water on the assumption that the extra campden in the boil water is still available to treat the top-off water. I do this because measuring the whole amount at one time seems more accurate than measuring two half-size pieces. I’m not getting the chlorine off flavors, but is this really good practice?

One could argue that during the boil two things will happen after the metabite converts to sufurous acid
1) H2SO3 --> SO2 + H2O
2) SO3-- + oxidized something ---> SO4-- + reduced something

Both of these reactions would remove SO3-- which would otherwise be available to reduce chloramine. This reasoning says it is not good practice though the fact that you do not get chlorphenolic flavors suggests either that removing chloramine from half the water is effective enough or that neither 1 nor 2 takes place to an extent that damaging levels of chloramine are left in the kettle.

It's hard for me to imagine that removing chlorine (my water has chlorine - not chloramine) from half of the water could be effective enough. I'm going to guess that the second possibility must be what is happening. In that case, I'll start treating the top-off water as well, both to avoid future problems and possibly improve the quality of the beer all the time. There might be a borderline off flavor that just isn't being picked up.

I really appreciate your response, and the whole thread for that matter.

The explanation with chlorine only is even simpler - heating and/or allowing the water to stand is sufficient to let the chlorine escape from the small quantities of water used in home brewing. That aside, even were it chloramine, getting rid of half of it could work. Lots of people brew with chloramine treated water without a trace of trouble and when you say 'chloramine' they say 'huh?'.

Another factor I didn't consider last night is that one of the main sources of phenolics (the other half of chlor-phenolic) is the malt husks. If you are not using grain there are no husks, thus less phenolics (hops yield some) and hence less chlorphenolic formation potential.

It takes an incredibly small amount of chlorine or chloramine to impart detectable chlorophenol in beer...even a recently washed serving glass that is still wet with chlorinated water will instantly create chlorophenol. Yes, in a finished beer!

Adding a slug of chlorinated or chloraminated top up water to the kettle or fermenter could easily do it too. Be sure to remove all chlorine compounds from any water that ends up in your beer.

Sorry AJ, the lack of husk or hop doesn't reduce the chlorophenol potential.

mabrungard said:

It takes an incredibly small amount of chlorine or chloramine to impart detectable chlorophenol in beer...even a recently washed serving glass that is still wet with chlorinated water will instantly create chlorophenol. Yes, in a finished beer!

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You need to say 'might'. I just put 10 uL of 5 trade % bleach in 100,000 uL of beer (5 ppm available chlorine), sniffed and waited a while before tasting (the things we do for science!). The beer smelled of chlorine for a while. That evenutually dissipated (scrubbed out by bubbles?). There was at no time any hint of a plastic, smokey or bandaid like smell or taste. I did this experiment to confirm what common sense tells us. Part of conditioning involves coalescence and precipitation of polyphenols. There are doubtless traces of phenols left in the beer but apparently not enough to form chlorphenols with even a whopping level of free chlorine - at least not in a couple of minutes time frame.

Clearly Martin would not have posted this if he hadn't experienced it. Perhaps beers that aren't as well conditioned retain more phenols in solution. But we cannot say it will happen because I just demonstrated that it doesn't always.

mabrungard said:

Adding a slug of chlorinated or chloraminated top up water to the kettle or fermenter could easily do it too. Be sure to remove all chlorine compounds from any water that ends up in your beer.

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Here at least the subjunctive is being used. Yes it could but we still have the evidence that lots of brewers using chloraminated water do nothing about it and brew very good beers. I've had many of them.

I am not, of course, advocating that any particular brewer chance it. If he knows he has chloramine, he should use campden tablets. If he knows he has chlorine he should let the water stand long enough that the chlorine odor evanesces (or use campden tablets).

mabrungard said:

Sorry AJ, the lack of husk or hop doesn't reduce the chlorophenol potential.

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That says that phenols from husks and hops cannot (or don't or don't preferentially) form chlorphenols. I'm interested, thus, in which sources of phenols can (or do or do preferentially) and what it is about the chemistry of hop and husk phenols that prevent them from reacting with chlorine while these other phenols do.

ajdelange said:

Clearly Martin would not have posted this if he hadn't experienced it. Perhaps beers that aren't as well conditioned retain more phenols in solution. But we cannot say it will happen because I just demonstrated that it doesn't always.

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The one time it occurred was in the Portland OR airport at a local brewery's bar. They had just washed the glasses in the typical glassware dunkings and served the beers in those glasses. I complained and thought that the beer was bad. They had apparently had this happen before since they dumped that beer and served the same beer in a properly rinsed and dried glass and there was no problem. Happy me.

Does the Campden need to be added before mash, or can it be added to the BK?

I measure out my strike and sparge water as I need it, not all at once.

drksky said:

Does the Campden need to be added before mash, or can it be added to the BK?

I measure out my strike and sparge water as I need it, not all at once.

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Yes, it MUST be added to the water prior to contacting any malt constituents or chlorophenols will be created.

Regarding the chart in the first tab. The ions released are given in mg. Is that mg/L?

What I'm getting at is how would I adjust my water spreadsheet to account for that. If it's just straight mg, that seems like a really insignificant amount and nothing would need to be done.

I've also heard anecdotal reports from people that campden tabs take their ph down. But, the numbers I've read from others seems a lot more significant than the reduction in alkalinity on that chart.

cervid said:

Regarding the chart in the first tab. The ions released are given in mg. Is that mg/L?

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In the chart it is mg. It takes 1.564 mg of potassium metabite to neutralize 1 mg of free chlorine and 3.127 mg to neutralize chloramine with a free equivalent chlorine content of 1 mg whether that mg be dispersed throughout 1 deciliter, 1 liter or 1 gallon of water.

cervid said:

What I'm getting at is how would I adjust my water spreadsheet to account for that. If it's just straight mg, that seems like a really insignificant amount and nothing would need to be done.

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If the water's chlorine concentration is 1 mg/L then the required metabite is 1.564 mg/L or 3.127 mg/L. Or, looked at another way, if your water has chloramine at 1 mg/L and you are treating 20 L you have 20 mg of chloramine to deal with requiring 20*3.127 mg metabite which is 20*3.127/20 mg/L.

cervid said:

I've also heard anecdotal reports from people that campden tabs take their ph down. But, the numbers I've read from others seems a lot more significant than the reduction in alkalinity on that chart.

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Those numbers are in ppm as CaCO3 which they wouldn't be unless the mg of chlorine/chloramine were also per liter so I see where your confusion on the first question stems from. The alkalinity numbers should be divided by 50 which gives the number of mEq of protons released per mg of chlorine or chloramine and puts them on the same basis as the other numbers in the table. I had never noticed this! As 1 mg of chlorine is 1/35 = 0.029 mEq you cant expect much more hydrogen ion than that to be formed.

Or, looked at another way, if your water has chloramine at 1 mg/L and you are treating 20 L you have 20 mg of chloramine to deal with requiring 20*3.127 mg metabite which is 20*3.127/20 mg/L.

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Just looking at this now.. Doesn't that equation just come back to 3.127 mg/ml? That was an arbitrary equation in that, if I had 2 mg/ml of chloramine, then the ppm would double..

So.. couldn't I just take the mg of ions in either of those charts and multiply by a factor of whatever the mg/ml concentration of chlorine or chloramine is, respectively?

So, in your above example equation, I would be adding 2.70 mg/ml of SO4, when using the tablet in the prescribed amount we have been discussing? If my concentration of chloramine was 2 mg/ml, I would be adding 5.4 mg/ml of SO4, for instance?

Edit: I just heard back from my water guy regradring the municipal well. They chlorine where I am is between .2 and .5 ppm. Considering I will almost always be diluting my water, I'm not that worried about it.

Let's do an example which I hope will make it clear. Your water report says your water contains 2 mg chloramine per liter. You are preparing 40 L (about 10 gal) for brewing. The table says that each mg of chloramine requires 3.127 mg of K2S2O5 and produces 2.70 mg of sulfate and cancels 1.43/50 mEq of alkalinity. Thus for each liter of water treated you will need 2*3.127 = 6.254 mg of K2S2O5 per liter, will obtain 2*2.70 mg of sulfate per liter and remove 2*1.43/50 mEq alkalinity per liter equal to 2*1.43 ppm as CaCO3. Since you are working 'per liter' here the alkalinity can be written a 2*1.43 ppm as CaCO3. The total dose of metabite is, as you are treating 40 L 40*6.254 = 250 mg or about 1/2 a campden tablet.

Or you can multiply the 40 L by 2 mg/L to calculate that you must treat 80 mg chloramine. As each requires 3.127 you will need a total of 80*3.127 = 250 mg. Sulfate produced will be 80*2.70 mg. The mg/L, the number likely to be of more interest is 80*2.70/40 = 5.40 mg/L. 80 mg chloramine neutralizes 80*1.43 mg as CaCO3 alkalinity. Per liter that is 80*1.43/40 = 2*1.43 mg/L as CaCO3 (ppm as CaCO3). Thus it doesn't matter whether you prefer to work with total mg or mg/L. You get the same answer and well you should.

Excellent info AJ.

I have been doing all grain for many years and have always bought bulk water from the grocery for a few dollars that claims to be chlorine/chloramine free. At my level much of this information is over my head at this point in the game anyway.

I know my local water supply has chorine/chloramine, would you suggest I find a printout of my municipal water supply and adjust with camden tablets as needed for the time be? Any other pointers? I appreciate your time and thanks in advance.

You can usually be guided by the results of the standing over night test. If you pass that then you don't need to do anything. If you don't then use half a tablet in 20 gallons of water treated. That will cover most situations. If you really want to be precise obtain a free and total chlorine kit from Hach or Lamotte or a pool supplier, measure the chlorine and chloramine and then use the tables to determine how much of a Campden tablet. Using too much campden won't hurt anything.

Awesome, thanks!

Okay, heres my question for one of you who's a chemistry wizz.

I have a 30L HLT but usually require about 35L for my all grain batches. I also add Potassium Metabisulphite at a rate of approximately 0.0666g/L.

If I were to fill my mash tun to the 25L mark, treat with K2S205, mash in, and then add 10L more of water [to my mash tun to use for sparging] **edit**...

- would the additional water have to be pretreated before being added to the HLT.

OR

- could the additional water be added and then the entire mixed water supply be treated with another hit of K2S205 proportionate to the amount of water added.

I think the latter is correct but have no solid grounds for my reasoning.

I think either way would be okay, but if you've already mashed in, I think you would be more likely to ensure the campden tablet is dissolved in if you added it to the second, separate water addition.

Thanks Matt, I realize I wasn't clear. The additional water would be added to the water already in my hot liquor tank.

Possibly a stupid question, but I am not a chemist, so here goes: What effect will treating water with campden have on the ph of the water (and really, the ph of the mash, eventually)?

If you go back to #1 here you will see that for each mg/L chlorine neutralized by metabite 2.11/50 = 0.042 mEq/L of hydrogen ions are released while for each mg/L chloramine it is 0.028 mEq/L. These are not appreciable as they correspond to neutralization of water alkalinity of respectively 2.1 and 1.4 ppm as CaCO3 and a typical mash has buffering of 30 - 40 mEq/kg-pH.

Devin said:

Possibly a stupid question, but I am not a chemist, so here goes: What effect will treating water with campden have on the ph of the water (and really, the ph of the mash, eventually)?

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No effect that is noticed. You can ignore it.

Kal

Sorry to bring this thread back from the dead, and maybe this has been covered somewhere, but several searches failed to find it.

Is there a way to account for the addition of metabisulfite in the Bru'n water spreadsheet? I'm probably not understanding the reactions well, but will Campden affect the addition of CaCl or gypsum?

TheMadKing said:

Sorry to bring this thread back from the dead, and maybe this has been covered somewhere, but several searches failed to find it.

Is there a way to account for the addition of metabisulfite in the Bru'n water spreadsheet? I'm probably not understanding the reactions well, but will Campden affect the addition of CaCl or gypsum?

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Have a look at the table in #1. It lists the things that potassium and sodium metabisulfite add to water in neutralizing chlorine and chloramine. Both chloride (from reduction of chlorine) and sulfate (from oxidation of sulfite) are added. Also note the release of some hydrogen ions (cancel alkalinity and lower pH). None of these effects should be noticeable.

ajdelange said:

Have a look at the table in #1. It lists the things that potassium and sodium metabisulfite add to water in neutralizing chlorine and chloramine. Both chloride (from reduction of chlorine) and sulfate (from oxidation of sulfite) are added. Also note the release of some hydrogen ions (cancel alkalinity and lower pH). None of these effects should be noticeable.

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I read it, and I guess my real question is: campden only reacts with free chlorine and chloramine ions and will not affect bound chlorine such as CaCl or NaCl correct?

And therefore it does not matter if I add the Campden before or after my CaCl/NaCl additions to my brewing water?

Metabite changes chlorine and chloramine to chloride and ammonia (chloramine only) and in so doing is converted to sulfate. As a consequence its use increases the concentration of all three of these ions (and H+ too) but no, it does not matter whether you add it before or after chloride and/or sulfate supplementation (to any appreciable extent).

Thank you AJ, sorry if I was being dense as usual

Not a problem. If you remember redox from high school or college chem then all should be clear. If you don't or if you were never exposed then it wouldn't be so clear and asking for additional explanation is not unreasonable.

good info. Thanks!

this thread should be a sticky. AJ, extremely informative.

If you came here via a link you would have no way of knowing it but it is indeed a sticky.