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ArcLight 09-10-2012 09:08 PM

Campden Tablets - what salts will they add?
 
In addition to removing Chlorine/chloramine, will the Campden tablets add various salts that must be reflected in a spreadsheet/application such as BrunWater or EZ Water? (ex: X mg of salt S, and Y mg of salt T)


Or will 1/2 of a tablet for 7-8 gallons have negligible amounts of salts?

aiptasia 09-10-2012 09:18 PM

Negligible. Worry not. Wiki: http://en.wikipedia.org/wiki/Campden_tablets

mabrungard 09-10-2012 09:29 PM

Scroll down to section 4.1.3 to see a discussion on metabisulfite use for dechlorination at the following page:

https://sites.google.com/site/brunwater/water-knowledge

rhamilton 09-10-2012 09:52 PM

Quote:

Originally Posted by mabrungard (Post 4402258)
https://sites.google.com/site/brunwater/water-knowledge

4.1.3 Metabisulfite (Campden Tablet) addition is effective for chlorine and chloramine removal. The tablets are either potassium metabisulfite or sodium metabisulfite. Both are effective in disinfectant removal. When sodium content in the brewing water is a concern, potassium metabisulfite may be preferred. Moderate potassium content in brewing water generally has little effect on brewing performance or taste. Adding these compounds at a rate of about 9 milligrams per liter (~35 milligrams per gallon or ~1 tablet per 20 gallons) or (~1 tablet per 75 liters) will dechlorinate typical municipal water and leave residual concentrations of about 3 ppm potassium or 2 ppm sodium (depending on the chemical used) and 8 ppm sulfate and 3 ppm chloride. These ion contributions are relatively insignificant and can be ignored in practice.

So if you are using 1/4 tablet for 5 gallons, add:

3 ppm Potassium or 2 ppm Sodium, depending on the variety, and...
8 ppm sulfate & 3 ppm chloride

Not significant by any means but I'm a stickler for detail :mug:

ArcLight 09-11-2012 01:04 AM

Thank you Martin.

>>So if you are using 1/4 tablet for 5 gallons, add:

But total water, taking into account boil off, and losses (grain, trub, hops), is closer to 7.5/8, so you need 1/3 of a tablet, or even half a tablet.

ajdelange 09-11-2012 01:59 PM

The one tablet per 20 gallons dose was based on

1. Campden tablets that weigh 692 mg
2. Campden tables made of 100 percent potassium metabisulfite
3. Water chlorine equivalent of 3 mg/L all as chloramine.

The amount of bisulfite required depends on the relative mix of chlorine and chloramine. After standing over night there should be no chlorine, the total chlorine should be reduced and, as water authoirites seldom go to the extent of as much as 3 mg/L, the demand for bisulfite should be less.

Fortunately there is a simple test for chloramine: if you can smell it there's enough of it to be of concern. Therefore, I recommend crushing a Campden tablet and dissolving it in some warm water (this can be difficult - it doesn't all have to be dissolved though). Pour a little of the liquid into the water being treated. Now stir and smell the water. You have added just the right amount when the chlorine smell is gone. If you have added too much the water will now smell of sulfur dioxide. This is not a problem. It will do good things for your beer (some people add metabite in the kettle).

In the 3 mg/L chloramine case the treatment will result in 7.1 mg/L sulfate, 1.5 mg/L ammonium (yeast nutrient) and 3 mg/L chloride plus 3.3 mg/L potassium or 1.8 mg/L sodium depending on whether the K or Na salt was used. Also, a little free goodie, 5.2 ppm as CaCO3 alkalinity is neutralized.

All the details can be found in a .pdf at hbd.org/ajdelange. Look for the Chlorine - Chloramine article. The numbers come from Table 5.

ArcLight 09-11-2012 02:25 PM

Thank you AJ.
Thanks for the link too!

In my area of NJ, Chloramine is 0.6 - 1.1, which is well below 3.0.
(Chlorine is .56)

So I think a 550MG tablet (thats the size from the Home Brew Shops) will handle more than 20 gallons, so 1/3 of a tablet for 7.5 gallons seems about right.


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