any reason we need to wait for the mash? could i just throw it (campden) while i am heating my strike water
yes, in fact I think this is standard practice.
Put the campden right in the strike and sparge water if you have chlorine/cloramine issues. The reaction go very fast, so no need to so it some tiem before you brew.
Like I said above, putting it in the mash is to use it as an anti-oxidant, not to remove chlorine/chloramines.
The sulfites get boiled off.
I would suggest crushing the tablet if you’re in a hurry. They don’t dissolve real quickly in tablet form.
+1 I use my mortar and pestle to powder it up and drop it into the water I’m going to use the night before brewday. It works much quicker than that but it’s part of my setup process so I can hit the ground running in the morning.
Activated Carbon (AC) does remove chlorine and chloramine from water. That comes from my former professor at University of Florida who specializes in activated carbon treatment and research. He did his PhD at Penn State where the top experts in activated carbon chemistry are. Any source that tells you that AC cannot remove chloramines is incorrect.
Charcoal is not necessarily AC. You can convert a carbonaceous material into nearly pure carbon in an oxygen-less retort oven, but its not AC until you have treated it in a specific way. While the carbon is very hot, injecting oxidants like steam, carbon monoxide, carbon dioxide, and hydrogen is how AC is created. Air or oxygen are not used as an oxidant since that acts too quick and destroys the carbon matrix. The result of the activation is that teeny ‘pocks’ are etched throughout the entire carbon matrix, creating a huge surface area. This occurs on both the exterior of the particles and deep inside the particles.
As pointed out in some posts above, chloramine removal is more difficult than chlorine removal. For that reason, the residence time for the water to be in contact with the AC is greater. For many contaminants, AC actually adsorbs the contaminant to the carbon. That is not the case with chlorine and chloramine. For them, there is a chemical reaction between the AC and the chlorine compound that destroys the compound and consumes the carbon.
Campden tablets are very effective in removing chlorine and chloramine. This is a well understood chemical reaction that is frequently used in wastewater treatment. As mentioned, dosing at a rate of about 1 tablet per 20 gallons will result in consuming up to 3 ppm chlorine or chloramine. That level of chlorine residual is typically on the high end of disinfectant in water distribution, but sometimes utilities have to superchlorinate the system for various reasons. The reaction produces sulfate and chloride at very low ppm levels. You can read more about this on the Water Knowledge page of the Bru’n Water website.
I suggest that a brewer would want to avoid overdosing their water with too much Campden tablet since that will result in an excess of sulfite in the water. You may know that wine makers add far more Campden to their grapes to kill wild yeasts. That does result in elevated sulfites in their wine and requirements for warnings to their drinkers. Some have mentioned that sulfites are boiled out of the wort, but I’m not sure of that. A quick web search does not produce any confirmation that sulfites are boiled out or converted. For that reason, I would try to match the Campden dose to the amount of chlorine compound in the water and the volume of water to treat.
Do be careful if your utility uses chloramine in the water. Many utilities change over to chlorine disinfection for a short period (typically early spring) to improve the disinfection in their pipes. Chlorine is a much more effective disinfection agent than chloramine, so more ‘bugs’ get killed in the system this way. One side effect is that the water smells much more ‘chloriney’ during this period. Part of the reason is that chlorine is more volatile than chloramine and it goes into the air much easier where you can smell it.
Having a simple swimming pool or aquarium test kit on hand to check the level of chlorine compound in your water is a good way to avoid overdosing with sulfites.
Martin,
I read on your website that using campden tablets at the rate of 1 tablet per 20 gallons leaves residual concentrations of 3 ppm potassium, 8 ppm sulfate, and 3 ppm chloride.
Is this the same sulfate as is found in gypsum and commonly added to brewing liquor?
Further, in your post above you vary between stating that campden tablets add sulfate and that they add sulfite. Are they the same or is one of those references a typo?
I’ve been using 1 full tablet for 15 gallons. Doesn’t seem to be a problem, but now I’m wondering if I should cut back a little.
Personally, I hate the smell of sulfur which is commonly encountered here in Florida from low-tide and/or non-potable water sources used for lawn irrigation. I also seem to be particularly sensitive to it when tasting beer styles known to have acceptably high sulfate levels (e.g., bitters).
Martin, can you explain the difference to us between sulfate and sulftite? I don’t buy the notion that sulfites are boiled off. That is new information to me.
If sulfites don’t boil off, then something I read on the internet was wrong! Oh no!
Easy and cheap chlorine/chloramine test strips here:
http://www.oceanproaquatics.com/shop/lifegard-chlorinechloramine-test-strips-p-3427.html
A good local aquarium/pond supply center might also have them, where I originally found them. I have also seen other brands.
The strip has two test pads, one shows total chlorine and the other shows just free chlorine. If free chlorine is clean (white) but total chlorine is pink, then you still have some chloramine in there.
To me the extra $2.50 or so each for 3 x 2-gallon bottled spring water is a small price to pay for good beer. Every batch has come out good since I started using spring water. Prior to that (when I was doing Mr Beer) I discovered the hard way what chloramine treated water makes beer taste like. In some ways I’m quite glad I started with Mr Beer because I discovered the water issue before I was spending $30-40+ on ingredients for a beer kit (I got a three pack of Mr Beer stuff for $25).
Now I can use the Mr Beer keg for experimental secondary fermentations too.
I agree that it’s a small price to pay. For my very pale beers, like pilsner, I still do buy distilled water, which costs like $10-12 for the batch. For beers where I can use my tap water the water costs whatever miniscule amount 15 gallons of tap water costs from the water company plus $0.03 for the campden.
I think what’s confusing people about the campden is that the ammonia produced by the campden’s reduction of chloramine is what boils off, leaving chloride behind. The sulfite is oxidized to sulfate.
Campden tablets are sulfites and gypsum is sulfate. They are not at all the same in brewing.
Veldy
Hah! What is a Gator doing in Indiana? 
The sulfur smell that you describe is hydrogen sulfide. H2S. Often refered to as “rotten eggs smell.” It is common in shallow groundwater. Much of Florida’s irrigation water comes from shallow wells. H2S is also a product of bacterial breakdown of organic matter, such as sargasso seaweed rotting at low tide, or anaerobic mud flats exposed at low tide.
Deep water wells in Florida also have H2S dissolved in their water. The H2S is a dissolved gas that is removed by aeration of the well water over a cascade or through an aeration tower, or it is reacted with ozone injection. H2S removal is quite necessary to make much of Florida’s potable water platable.
Both sulfite and sulfate are divalent anions. The sulfate molecule has an additional oxygen atom:
Sulfite = SO32-
Sulfate = SO42-