Campden Tablets (Sulfites) and Brewing Water

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ajdelange

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Brewers obtaining their water from municipal systems of moderate size and up are likely to find that the supplier has used chloramine as part of its disinfection process. Chloramine is not as good a disinfectant as plain chlorine but it is more stable which means that it persists in water longer than chlorine does so that no matter where you are on the distribution system there will still be a good chloramine residual in your water when it arrives at your house and it will be safe to drink. This same stability which is beneficial from the safe water point of view presents a problem for brewers: chloramine is harder to remove from water than chlorine is by the conventional means of allowing the water to stand or by heating/boiling it. Both those methods do work but they take longer. Standing can, depending on the level of chloramine, take days and boiling hours.

Choramine is simply ammonia (NH3) in which one or more of the hydrogen atoms has been replaced by chlorine thus NH2Cl is monochloramine which is much more common than dichloramine or nitrogen trichloride, the other two members of the family. It is typically introduced into drinking water by injecting ammonia gas into water which has previously been chlorinated.

The first thing a brewer wants to know is if chloramine is a problem for him and, of course, the second is what he should do about it if it is. It is quite simple to test for chloramine. Simply draw a tumblerful of the water in question and let it stand over night. That is long enough for any free chlorine to leave the water meaning that any detectable chlorine smell the following day is from chloramine. If, the next morning, no chlorine smell is noted confirm this by pouring the water back and forth into another glass which sniffing in the vicinity. Failure to detect chlorine odor while doing this verifies that chloramine is not present at significant levels. If chlorine is smelled then chloramine is indeed present. Brewers can also buy inexpensive test kits but need to be sure that any kit tests for both total and free (with the difference being chloramine) chlorine.

Chloramine can be removed from drinking water by filtration through active carbon filters but the contact time required is long so that unless the filter has very large contact area the flow rate will have to be small. RO systems contain activated carbon filters to protect the membranes from chlorine/chloramine so brewers using those will not have to worry further about chloramine other than being sure they are replacing the filter frequently enough.

The simplest way to surely remove chloramine is through the use of sodium or potassium metabisulfite often sold in the convenient form of 'Campden Tablets' by brewing and wine making suppliers. To use Campden tablets put one in a glass and crush it with a spoon. Add some warm water and stir. It will be hard to get it all to dissolve but it doesn't have to. Put the water to be treated in a pot, kettle or what have you. Add bits of the liquid from the glass a little at a time and stir. Then agitate the treated water and sniff. If you still smell chlorine add a bit more of the liquid. Keep doing that until you don't smell chlorine any more. The reaction is instantaneous. If you smell a bit of sulfur dioxide, that's fine and confirms you have gotten rid of all the chlorine - chloramine and any free chlorine as well. If you conclude that you smell sulfur dioxide be sure it is coming from the water - not your hands or the glass with the Campden tablet in it. The latter will smell strongly of sulfur dioxide (metabite is often referred to as 'solid sulfur dioxide'). You should need half or less of a Campden tablet to treat 10 gallons of water. If you find you are needing more you are probably doing something wrong as 1 typical tablet will treat 20 gal of water chloraminated (no free chlorine - this is the worst case) to 3 mg/L free chlorine equivalent. This depends somewhat on the weight of the metabite in the Campden tablet and whether the salt is potassium or sodium metabisulfite. If Campden tablets are not available from your LHBS or by mail order you can use potassium (or sodium) metabisulfite available from wine making hobby suppliers. Doses are given in the table below.

Brewers are often concerned about the consequences of adding metabite to their water. They are not significant. When chloramine is reduced by metabite the reaction products are ammonium ion, chloride ion, sulfate ion, hydrogen ion and potassium or sodium ion depending on whether potassium or sodium metabisulfite was used. For each mg/L of chloramine destroyed 0.51 mg/L ammonium ion is released. This is a beneficial yeast nutrient. Also 2.70 mg/L sulfate and 1 mg/L chloride ion and enough hydrogen ion to neutralize 1.43 mg/L as calcium carbonate alkalinity are released into the water as are either 1.1 mg of potassium or 0.65 mg of sodium. As chloramine levels rarely exceed 3 mg/L the recommendation of 1 Campden Tablet per 20 gallons of water treated covers the vast majority of cases. The method of gradual addition given above insures that the minimum amounts of these ions are introduced but one can always choose to be on the safe side and use the whole tablet for 20 gallons. Unreacted metabolite becomes sulfur dioxide in solution which either is driven off when the water is heated or reduces something in the mash and this is a good thing.

The table below shows how much of what is needed to remove each mg/L chlorine and chloramine and how much of what byproducts are produced. Details of the calculations can be found at http://wetnewf.org/pdfs/Brewing_articles/BT_Chlorine.pdf

As there have been several questions recently (1/13) about the use of ascorbic acid to reduce chloramines I'm adding the following remarks:

Ascorbic acid is effective at reducing chloramine. The required dose is 4.97 mg/L of water treated per mg/L equivalent free chlorine (if the water report lists chloramine at 2 mg/L then the equivalent free chlorine is 2 mg/L). This is equivalent to 1.13 grams for the 20 gal at 3 mg/L that is treatable with 1 Campden tablet. My concerns with ascorbic acid are 3:
1. It has a finite shelf life
2. While ascorbic acid does not behave as an acid in the chloramine reaction any excess does. If, for example, you think chloramine is at 2 mg/L and it is actually at 1 you will add an extra 4.97 mg/L. As it's a pretty strong acid that's enough to lower the pH of distilled water to pH 4.29. Water with higher alkalinity will not be so dramatically effected. Water with alkalinity of 10 would go to pH 6.22. While this isn't probably terribly significant in a mash that has typical buffering capacity (much greater than that of the water) you should, if using ascorbic acid, use the incremental addition process and stop as soon as the chlorine smell is gone.
3. The products of the reaction are, as with metabite, ammonium ion and chloride ion but rather than sufate ion we get oxidized ascorbic acid (dehydroascorbic acid) which is pretty chemically active. For example, it degrades valine to isobutyraldehyde and, in the presence of certain metal ions, can act as an oxidizer. That is why, when it is added to beer to keep beer in a reduced state (stabilize it) it is always accompanied by metabite.

Given these concerns I recommend the use of metabite rather than ascorbic acid.

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+1 on the information above.

An additional note regarding the use of chlorine and chloramine in water systems. The primary driver that causes a utility to NOT use chlorine is the presence of dissolved organic matter that reacts with the chlorine to create carcinogenic compounds in the water. Chloramines are less likely to create those carcinogens.

Given the extra cost to create chloramines and their reduced disinfection effectiveness, every utility would use chlorine as their disinfectant of choice if they could. But the presence of the dissolved organic matter forces them to use chloramine.

Since it is slightly unclear above, chloramines are detected only through a Total Chlorine test while chlorine is detected through the Free and/or Total Chlorine test.

If your water contains chloramines, consider the use of metabisulfite as your primary removal option. As mentioned above, using activated carbon filtration to remove chloramine requires a very slow flow rate. For instance, the flow rate through a typical 10-inch undersink cartridge would require that the rate be less than 0.1 gal/min. That makes metabisulfite treatment much quicker and the effect of the metabisulfite addition is negligible on water quality.
 
I found out that my city uses chloramine by getting my city's water report.

Buy a pill cutter / crusher combo. Makes life easier.
 
I've been using campden tablets ever since I read AJ's more scholarly research paper on the topic. I couldn't believe that it was such a simple solution.

I've just been crushing the tablet and dumping the powder right into the bucket of brewing liquor. Is there an advantage to using the intermediate glass o'water, other than the opportunity to add the stuff in more limited amounts? I'm not terribly concerned about the reaction products.
 
I borrowed an idea I read in one of AJ's posts and now crush 3/4 of a campden tablet and put it in an empty White Labs yeast vial that I have lined at 1/3, 2/3, and 3/3 (thirds). I fill the vial with water up to the 3/3 line and shake it until the tablet is disolved. I'll pour out the solution in thirds for each 5 gallons of water I treat (I have both a 5 gal and 10 gal container to hold my brwing water).
 
How much does a tablet weight? I have potassium metabisulfite in powdered form.

I use potassium metabisulfite powder when I'm not using RO water. I use it at a rate of 0.025 grams/gallon. Got that dose rate from a BYO article I think. Kind of hard to measure accurately for small batches though if you don't have a scale with a resolution better than + / - 0.1 grams.
 
I use potassium metabisulfite powder when I'm not using RO water. I use it at a rate of 0.025 grams/gallon. Got that does rate from a BYO article I think. Kind of hard to measure accurately for small batches though if you don't have a scale with a resolution better than + / - 0.1 grams.
Thanks for the info. My scale will do that.
 
I use potassium metabisulfite powder when I'm not using RO water. I use it at a rate of 0.025 grams/gallon. Got that dose rate from a BYO article I think. Kind of hard to measure accurately for small batches though if you don't have a scale with a resolution better than + / - 0.1 grams.

If your scale doesn't have a resolution that is that precise, measure out a greater quantity, such as .25 grams (10 times as much) and disolve it in a measured amount of water. Use 1/10th of the solution in each gallon of water to be treated. Baby syringes work well.
 
How long does the effect from the campden remain active in water? For example, if I dissolve half a campden tablet in a glass and then add a tiny amount from that glass to my starter to dissolve its chloramine, can I leave the rest of the water in the glass over night and then add it to my mash and sparge water when I brew the next day (or days) and still achieve the same effect? Or does the campden have to be used immediately after introducing it to the glass? Will campden-treated water get rid of cloramine from new water that I add in?

Thanks
 
What's the first thing you notice when you play with Campden tablets? Your answer should be "I smell sulfur dioxide." Metabisulfite is often referred to as 'solid SO2' and it is indeed SO2 which destroys chloramine. The fact that you can smell the sulfur dioxide says that at least some of it is leaving the solution. Wait long enough and presumably enough of the SO2 will have escaped to render the solution less effective than when fresh. That said, it doesn't take much to do the job so that even if you let it stand overnight there may be enough SO2 left. Remember the simple test in the Sticky. If you can't smell chlorine then you have added enough SO2. It probably would be sensible to store unused solution in a tightly capped small jar. That will reduce the amount of SO2 which can get away.
 
What's the first thing you notice when you play with Campden tablets? Your answer should be "I smell sulfur dioxide." Metabisulfite is often referred to as 'solid SO2' and it is indeed SO2 which destroys chloramine. The fact that you can smell the sulfur dioxide says that at least some of it is leaving the solution. Wait long enough and presumably enough of the SO2 will have escaped to render the solution less effective than when fresh. That said, it doesn't take much to do the job so that even if you let it stand overnight there may be enough SO2 left. Remember the simple test in the Sticky. If you can't smell chlorine then you have added enough SO2. It probably would be sensible to store unused solution in a tightly capped small jar. That will reduce the amount of SO2 which can get away.

In which case storing with zero headspace would be ideal correct?
 
So, the way I read the original post, none of the metebisulfite remains in the water in that form, even if you have a low level of chloramines?

I know my water has chloramines, the water report tells me so, but I can't smell any. I use a half tab per 10 gallons. So I'm concerned that sulfites may remain in my beer and I know some people are sensitive to sulfites.
 
I really don't think you need to be concerned. You are using 1/2 tablet per 10 gallons. Vintners use 1 tablet per gallon - 20 times this - and they don't dilute with sparge water or boil. If you are concerned about excess use the titration method described in the original post.

Potassium metabisulfite is 57.6 % SO2. If you added 300 mg/10 gal (300 mg/37.8L) i.e. about half a Campden tablet in 10 gal, that would be 4.57 mg SO2 per liter. After dilution with sparge water, boiling, absorbtion of oxygen, reduction of other compounds and formation of adducts with aldehydes and reduction to sulphide and CO2 scrubbing in the fermenter very little of this would make it through to the beer. Much more would be produced by other sources (sulfate in the water, sulfur containing amino acids in the malt). For untreated beer you can expect SO2 at from 1 - 16 mg/L and, in Britain, where sulfites are added to beers to stabilized them, the statutory limit is 40 mg/L.
 
I'm very curious about this... I already use campden to treat chloramine but is there a accepted time length. What I usually do is treat it the night befrore at 1/2 a tab per 10 gallons and it's pretty spot on. Do I really need to treat the night before or could I get away treating it 30 minutes before I start to brew ? Thanks for the advice.
 
You could do it 30 seconds before you brew. The reaction is very fast but it does take some time for the metabite to dissolve. As people usually dose at a higher level than is really necessary (in terms of the actual chloramine level) this does not effect chloramine removal i.e. plenty dissolves to take care of the chloramine.
 
I use potassium metabisulfite powder when I'm not using RO water. I use it at a rate of 0.025 grams/gallon. Got that dose rate from a BYO article I think. Kind of hard to measure accurately for small batches though if you don't have a scale with a resolution better than + / - 0.1 grams.

+1

I've been using .022 per gallon, but close enough.
 
I'm curious if this could have a positive effect on a beer that's already been brewed? I have about 4 gallons of a Belgian Quad in a keg, and I get a distinct chlorinated-tasting solvent taste from it.

Could I just pop open the keg and stir a very, very amount of potassium metabisulfite into the Quad? What effect would this have on an already brewed beer?
 
Probably not but try it in the glass first. Bisulfite appears to offer promise as it has the potential to reduce nasty things like acetaldehyde and diacetyl in finished beer to less bothersome compounds but it also forms adducts some of which seem to taste almost as bad as the things you are trying to deal with.
 
Probably not but try it in the glass first. Bisulfite appears to offer promise as it has the potential to reduce nasty things like acetaldehyde and diacetyl in finished beer to less bothersome compounds but it also forms adducts some of which seem to taste almost as bad as the things you are trying to deal with.

Pretty much exactly what happened. The chloropenol harshness was moderately muted but at the expense of a harsh chalkiness. [I stirred as small of a pinch I could get into a single glass, which is probably too much]. I couldn't decide if it was an improvement or not. Probably not.
 
How long do the Campden tablets last??? I have a bottle in the fridge for 2 years or soo and though I don't mind getting more.... if I don't have to, why bother with the trip to the LHBS?

I notice on my bottle (LD carlson) there is no "born on" or "use by" date
 
The fact that they smell of sulfur dioxide says there is some decomposition taking place but as so little is needed to treat most water I don't think you need to worry with tabs that are 2 yrs old.

But I can't really answer your question. Ten years?
 
Since I have switched to AG I have been getting a strong plastic smell and taste to my beer. I have switched tubing, gone over my mash tun and made sure it's clean and I can attest that it is. I have, on 2 occasions now, used RO water to build my own brewing water. Low and behold no more plastic taste/smell! I've tried using a campden tablet in my tap water without success, however, I was adding it to the wort just as I was bringing it to a boil. Should I be adding it to my mash/sparge water instead?

I don't mind building my own water it's just that I typically brew on a whim and picking up RO water would require pre-planning (which is my wife's department).

Thanks for your time.
 
Since I have switched to AG I have been getting a strong plastic smell and taste to my beer. I have switched tubing, gone over my mash tun and made sure it's clean and I can attest that it is. I have, on 2 occasions now, used RO water to build my own brewing water. Low and behold no more plastic taste/smell! I've tried using a campden tablet in my tap water without success, however, I was adding it to the wort just as I was bringing it to a boil. Should I be adding it to my mash/sparge water instead?

I don't mind building my own water it's just that I typically brew on a whim and picking up RO water would require pre-planning (which is my wife's department).

Thanks for your time.
I'm pretty sure it is a 'pre-treatment'. You want the chlorne out before it has a chance to react with anything.
 
Correct. I add my potassium metabisulphite to my Hot Liquor Tank as the water is heating up in order to treate all my brewing liquor (both strike and sparge water).

Kal
 
The original post states what to do if your water has chloromine, but I'm not sure I understand what to do if like me, your water is treated with chlorine. Do you follow the same steps?

I've been using RO water with added Calcium Chloride up till now, but it takes forever to get 7 gallons of RO water from my system, so I thought I would try out my tap water on my next brew.
 
The original post states what to do if your water has chloromine, but I'm not sure I understand what to do if like me, your water is treated with chlorine. Do you follow the same steps?

I've been using RO water with added Calcium Chloride up till now, but it takes forever to get 7 gallons of RO water from my system, so I thought I would try out my tap water on my next brew.

Chlorine can be dissipated by just letting it sit in an open bucket for 24 hours.
 
Chlorine will off gas rather quickly (overnight) whereas Chloramine takes much longer. It is being used by a lot of municipalities because of this. It is faster to use Campden to remove it. The reaction takes only a few minutes if you crush them. I prefer the potassium based rather than the sodium which I've read can cause other off flavors although I don't know in what concentrations. I usually add 1/2 tablet crushed to 10 gallons of water I've already passed through my carbon filter.
 
Chlorine will off gas rather quickly (overnight) whereas Chloramine takes much longer. It is being used by a lot of municipalities because of this. It is faster to use Campden to remove it. The reaction takes only a few minutes if you crush them. I prefer the potassium based rather than the sodium which I've read can cause other off flavors although I don't know in what concentrations. I usually add 1/2 tablet crushed to 10 gallons of water I've already passed through my carbon filter.

Totally off gassing Clorine takes a lot longer than 24 hours, particularly in a deep bucket. If it were that fast, pools would be devoid of (unstabilized) chlorine overnight.

So use 1/4 crushed campden per 5 gallons, and stir it in well. I use potassium metabisulphite powder, but it is hard to measure such small quantities, like 1/40 of a teaspoon.
 
The typical swimming pool contains chloramine if it is used by kids with the nitrogen thoughtfully provided by them. It's pretty well known that if you approach a swimming pool and detect a strong chlorine odor it means that kids have been in it.

Carbon filters remove chlorine and chloramine though they won't do so completely if the flow rate doesn't allow sufficient contact time.

Campden tablets always work - for either form. The amounts of sodium and/or potassium introduced by the use of them is not enough to worry about. See the table in the original post.
 
I bought 10 lbs of Potassium Metabisulfite years ago, and at the time I was using it as a primary sanitizer for wines I was making. A solution of about 80g/gallon makes a potent food grade sanitizer, and it's a convenient sanitizer to use because it's actually the free SO2 gas produced by the sulfite that does the sanitizing work rather than the liquid, so everything in contact with the headspace of a container gets sanitized without even splashing or direct liquid contact. These days I mostly use starsan for beer, but I always keep some K-met solution around for sanitizing little parts or for storing carboys and fermenters in a sanitized state. It's also a good mold-mildew killer. When I brew I simply take a few mL of my stock K-met sanitizing solution and throw it into my brewing water. I've never had any issue with chlorine compounds, and I still occasionally use K-met solution as a primary sanitizer. It seems to work great for everything and I have so dam much of it.
 
How long does the effect from the campden remain active in water? For example, if I dissolve half a campden tablet in a glass and then add a tiny amount from that glass to my starter to dissolve its chloramine, can I leave the rest of the water in the glass over night and then add it to my mash and sparge water when I brew the next day (or days) and still achieve the same effect? Or does the campden have to be used immediately after introducing it to the glass? Will campden-treated water get rid of cloramine from new water that I add in?

Thanks

I too am curious about this. Is there any residual effect of the campden tablets to counteract new water additions of untreated water? Or is it a one shot deal?
 
I want make sure I understand correctly. Is there any reason not to use campden tablets? For example, if I have free chlorine in my water, is it better to boil or let it off-gas overnight? Unless there's a reason not to, it seems like it might be easier to just throw a campden tab in it while heating up my water and call it good.
 
Honestly, Campden is insurance against any chlorine and chloramine getting into the the mash. Even if you let the water rest over night, use Campden. It's cheap and easy. Make sure to dissolve the crushed tablet and stir very well. Takes just a few minutes, and while heating, the sulfur smell should gas off - maybe helped by additional stirring along the way.

If you want to follow German purity laws, then a hard boil is really the best bet and may help with alkalinity in the mash. I was never able to get all of the chlorine out of my tap water with a 24-48 hour rest.

I too am curious about this. Is there any residual effect of the campden tablets to counteract new water additions of untreated water? Or is it a one shot deal?
As the reaction occurs quickly, assume you need to treat any secondary additions.

I want make sure I understand correctly. Is there any reason not to use campden tablets? For example, if I have free chlorine in my water, is it better to boil or let it off-gas overnight? Unless there's a reason not to, it seems like it might be easier to just throw a campden tab in it while heating up my water and call it good.
Campden should address your concerns and simplify the process, however, as mentioned, a secondary benefit of pre-boiling water is the reduction of alkalinity when done properly. You will likely precipitate chalk if your water is saturated with bicarbonate. The roiling of the boil should force chlorine out of solution and break down chloramines, however it may not be worth the effort or fuel expense.

The sodium contribution of 1/2 or 1/4 tablet of Campden is minimal.
 
Campden tablet use is cheap insurance and the consequence of using too much is virtually non-existent. The recommended dosage of 1 tablet per 20 gallons of tap water leaves you with very little residue. In addition, the residue is composed of simple ionic components that are not hazardous or detrimental to beer or its flavor.

It's OK
 
Great info guys. I used to use campden and then stopped after making a carbon filtering system about 3 batches ago thinking that the filter would remove chlorimine. Looks like it makes sense to throw a campden tablet in the hlt just to be safe.
 
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