Get your HBT Growlers, Shirts and Membership before the Rush!


Home Brew Forums > Home Brewing Beer > Brew Science > How much Chloride/Sulfate is added to water when using Campden Tablets?
Reply
 
LinkBack Thread Tools
Old 01-05-2010, 09:59 PM   #1
kal
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
kal's Avatar
Recipes 
 
Join Date: Nov 2006
Location: Ottawa, Canada
Posts: 2,190
Liked 220 Times on 151 Posts
Likes Given: 6

Default How much Chloride/Sulfate is added to water when using Campden Tablets?

Hi guys,

I use one campden tablet (sodium metabisulphite) in 20 gallons of my city water to remove cholarmine. 1 tablet is supposed to be able to handle 20 gallons of water with 2 ppm chloramines. This is exactly the level of chloramine that I have.

In Brewing Classic Styles, John Palmer says the following about this:

"Both chlorine and chloramine are reduced to insignificant levels of sulfate and chloride ions (<10 ppm) within a couple of minutes at room temperature."

I also adjust my minerals (salts) based on style using www.ezwatercalculator.com.

My city's S04 and Cl are already very low (Cl=6, SO4=26). My chloramine is at 2ppm. If wanted to be more accurate with my salt additions should I add some points to my Cl and S04 counts because I use campden tablets or is really that insignificant? Adding 10ppm to my existing Cl count is nearly 3x as much!

Kal


kal is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2010, 08:48 PM   #2
martinworswick
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2008
Location: southernlakes,new zealand
Posts: 285
Liked 3 Times on 3 Posts
Likes Given: 2

Default

i'm also interested in the answer to this, less than 10ppm would raise my chloride and sulphate to around 11ppm and 18ppm

__________________
martinworswick is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2010, 09:02 PM   #3
Scimmia
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2007
Location: QCA, Iowa
Posts: 959
Liked 5 Times on 5 Posts

Default

It would depend on your specific water's level of chlorination, so I don't think anyone's going to be able to answer that for you. At that low of levels, though, the chloride/sulfate levels are pretty much useless anyway

__________________
Scimmia is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2010, 09:09 PM   #4
GilaMinumBeer
In yo' garage, steelin' yo parts.
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
GilaMinumBeer's Avatar
Recipes 
 
Join Date: Jan 2008
Location: Oblivion
Posts: 48,868
Liked 4955 Times on 4522 Posts
Likes Given: 60

Default

I'd further be curious how to calculate Sodium or Potassium contributions and sulfite addition.

__________________
GilaMinumBeer is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2010, 09:21 PM   #5
kal
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
kal's Avatar
Recipes 
 
Join Date: Nov 2006
Location: Ottawa, Canada
Posts: 2,190
Liked 220 Times on 151 Posts
Likes Given: 6

Default

Quote:
Originally Posted by Scimmia View Post
It would depend on your specific water's level of chlorination, so I don't think anyone's going to be able to answer that for you. At that low of levels, though, the chloride/sulfate levels are pretty much useless anyway
Both good points. My water's chloramine level is 2 ppm which I believe is fairly standard.

Kal
kal is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2010, 09:34 PM   #6
martinworswick
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2008
Location: southernlakes,new zealand
Posts: 285
Liked 3 Times on 3 Posts
Likes Given: 2

Default

Quote:
Originally Posted by Scimmia View Post
It would depend on your specific water's level of chlorination, so I don't think anyone's going to be able to answer that for you. At that low of levels, though, the chloride/sulfate levels are pretty much useless anyway
i knew my levels were low and have been adjusting them, but until i read this i didn't know if i was "over adjusting" them
__________________
martinworswick is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2010, 09:41 PM   #7
Scimmia
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2007
Location: QCA, Iowa
Posts: 959
Liked 5 Times on 5 Posts

Default

Quote:
Originally Posted by kal View Post
Both good points. My water's chloramine level is 2 ppm which I believe is fairly standard.

Kal
It is when the water leaves the plant, and while chloramine is nowhere near as volatile as chlorine, it will very likely be different by the time it reaches your house. Chlorine/chloramine will also change quite a bit, as they detect different things in the water.

Of course, all of that could be said about most things we look at on a water report.

At 2 ppm, I wouldn't worry about it at all. I'm no chemist, but I can't imagine you'd end up with more than 2 ppm total chloride + sulfate from it; you're taking on some sulfite from the camden, but releasing some other molecules in the reaction as well.
__________________
Scimmia is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2010, 09:47 PM   #8
kal
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
kal's Avatar
Recipes 
 
Join Date: Nov 2006
Location: Ottawa, Canada
Posts: 2,190
Liked 220 Times on 151 Posts
Likes Given: 6

Default

Thanks Scimmia.

What surprises me is how much my pH drops when I add one tiny campden tablet to 20 US gallons of water: It drops from 9.2 to 8.0. (Measured using a calibrated phep 5 pH meter).

Kal

__________________
TheElectricBrewery.com: A step by step guide to building your own electric brewery
My basement/bar/brewery build 2.0
kal is offline
 
Reply With Quote Quick reply to this message
Old 01-07-2010, 11:49 PM   #9
Rushis
Feedback Score: 0 reviews
Recipes 
 
Join Date: Nov 2009
Location: Pasadena, CA
Posts: 289
Liked 4 Times on 4 Posts
Likes Given: 1

Default

I don't for sure if this is how metabisulfite reacts, but here is my take on some reasonable redox reactions:

Eqn. 1: Na2S2O5 + H2O -> NaHSO3 (comproportionation)
Eqn. 2: NaHSO3 + NH2Cl + H2O -> NaHSO4 + NH3 + Cl- (reduction of chloroamine)

Eqn 3: 2NaHSO3 + O2 -> 2NaHSO4 (reduction of oxygen)
Eqn 4: NaHSO3 + H+ <-> SO2 + H2O + Na+ (SO2-SO3(2-) equilibrium)


The metabisulfite breaks down to sulfite in water, forming a strong reductant (eqn 1). The sulfite reduces the monchloroamine (eqn 2). From here you could estimate that your increase in chloride concentration will be equal the concentration of chloroamine in your water.

[Cl-] = [NH2Cl]

Determining the increase in sulfate concentration could be a little trickier. Every equivalent of chloroamine reduced generates one sulfate (eqn 2), but the NaHSO3 may also reduce oxygen (eqn 3). This is further complicated by the equilibrium between SO2 and HSO3- (eqn 4). At the very least you can set some upper and lower limits on the increase in the sulfate concentration. The sulfate concentration will be at least equal the concentration of chloroamine and less than or equal to twice the concentration of metabisulfite added.

The reduction of oxygen is where you could get a pH drop from. Assuming this is only reaction that generates an acidic species, NaHSO4 has a pKa of 1.9ish, a decently strong acid, it's possible to get a better estimate of the increase in sulfate concentration. If we knew the buffering capacity of the water (from carbonate and phosophate) and the corresponding pH change after addition of the metabisulfite, it's possible to determine the concentration of sulfate from the oxygen reduction. This value plus the concentration sulfate of chloroamine reduction should give an accurate estimate of the total increase in SO4(2-) if we make the assumption that any remaining sulfite is eliminated as SO2. A reasonable assumption considering the equilibrium would be skewed to SO2 as the pH decreases).

tl;dr Summary
[NH2Cl] = [Cl-] <= [SO4(2-)] <= 2 x [Na2S2O5]

Hope that's correct and helpful.

__________________

Rushis is offline
 
Reply With Quote Quick reply to this message
Old 01-11-2010, 12:29 PM   #10
jsullivan02130
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2008
Location: Boston, MA, USA
Posts: 205
Liked 1 Times on 1 Posts
Likes Given: 9

Default

In the final water episode of the Brewing Network podcasts with Jamil, John Palmer answers this question: it has a negligible effect and don't worry about it.

__________________

"There is nothing in brewing so complicated that a little effort can't make even more complicated."

jsullivan02130 is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Do campden tablets de-chlorinate water King of Cascade All Grain & Partial Mash Brewing 71 05-08-2013 09:53 PM
Calcium Sulfate vs. Calcium Chloride Grinder12000 Recipes/Ingredients 4 10-26-2012 05:35 AM
Help me to understand chloride - sulfate ratio hexmonkey Brew Science 78 01-27-2011 12:26 AM
Should I use campden tablets? Brandon O Mead Forum 26 01-13-2011 03:54 AM
how many campden tablets? plumber Cider Forum 4 11-14-2008 02:52 PM



Newest Threads

LATEST SPONSOR DEALS