# The effect of SMB for dichlorination on water profile

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#### StevoTosh

##### Learner
I'm hoping someone here may be able to help me with a puzzle that I have been grappling with.
My local drinking water supply is soft: (Ca:15/ Mg:1/ Na:4/ So4:8/ Cl2:6) No need for RO, I use this water exclusively for my brewing and add salts to adjust to target.
The average total chlorine is 0.9ppm. To remove chlorine and chloramine I generally use 1g/hL (.035oz/26.4G) of sodium metabisulphite prior to the salt additions.
According to Bru'n Water SMB has a noticeable affect on both sodium and sulphate levels as I would expect.
I know that when using sulphites to remove chlorine a sulphur-like aroma is released.
My questions are: Is the sulphur retained in the water as sulphates or does it disperse in gaseous form(s)? and how can these levels of Na and So4 be calculated?
Any help and input would be greatly appreciated.

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Para quantificar os elementos você teria que fazer os cálculos com base no balanço estequiométrico da reação do SBM e na molaridade dos produtos da reação .

Talvez trocar o SBM pelo Acido Ascórbico para inativar o cloro seja mais simples que quantificar nives extras de SO4 .

To quantify the elements, you would have to do the calculations based on the stoichiometric equilibrium of the SBM reaction and the molarity of the reaction products.

Perhaps replacing SBM with ascorbic acid to inactivate chlorine is simpler than quantifying extra levels of SO4.

PS: Sorry, my English language is bad

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Talvez substituir o SBM por ácido ascórbico para inativar o cloro seja mais simples do que quantificar níveis extras de SO4.
Esta sugestão é certamente a solução mais fácil, pois calcular quantidades molares seria difícil, considerando que não tenho meios para determinar a quantidade exata de cloro na água a qualquer momento. Eu vou tentar isso.

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After the reaction with hypochlorite or chloramines, the sulfurous compounds in SMB or KMB are converted to sulfate ions. You can read about that on the Water Knowledge page of the Bru'n Water website General 5 | Bru'n Water

When those SMB or KMB molecules aren't reacted in the water, they do remain as sulfite or bisulfite ions and those can get scrubbed from the wort as gaseous sulfur compounds during a boil. Of course, sulfite and bisulfite ions can react with oxygen in the water too. The way to avoid this issue all together, is to plan your SMB or KMB additions to more closely match the total needs of disinfectant and oxygen removal in the brew.

Thank you Martin
Your website is very useful and informative. I have referred to it often.
I now have an understanding of how I can best use SMB or KMB to eliminate hypochlorite and chloramines.
My original question however, had ( for me) a dual intention. I was hoping that I could glean some information on how to raise So4 levels without raising Mg or Ca too much in order to obtain a drier flavour profile in light ale through the use of SMB, simply because that is what I have on hand . I do not know if the campden tablets that I have are sodium or potassium MB, so I won't use them as I want to know the Na ion concentration.

While I have you Martin, a quick question: In Bru'n water, should I enter flaked maize as 'wheat/oat' grain type on the grain bill sheet?
I thank you again for your consideration.

I was hoping that I could glean some information on how to raise So4 levels without raising Mg or Ca too much [...]
That's a good question. Ca ion targets are ideally 30-150 ppm. I read that above 250 ppm it can start to hamper yeast activity, but you could add the extra (to get above 150 ppm) after fermentation has completed.

Sodium or Potassium MetaBisulfite will add their cation too, which is probably more of a flavor predicament than Ca.
I looked into using Ammonium salts, but the flavor profile of Ammonium is far worse than Na or K, so those aren't the solution either.

Now if you need to add an acid to reach your mash pH, or acidify the sparge, you could use Sulphuric Acid instead of Phosphoric or Lactic. Generally it would only be a relatively small contribution but it is 100% Sulphate.

Great info IslandLizard
you could add the extra (to get above 150 ppm) after fermentation has completed.
you could use Sulphuric Acid instead of Phosphoric or Lactic. Generally it would only be a relatively small contribution but it is 100% Sulphate.
I will look into this.
Obviously I will need to calculate molar quantities to determine the correct H₂SO₄ addition ( I'm not a chemist) but it is a welcome challenge.

For Concentrated 98% Sulphuric Acid:
MW_SO4_Anion = 96.0626 g/mol
MW_H2SO4 = 98.07848 g/mol
98% H2SO4 Acid Density at STP ~= 1.8437 g./mL

50 mL of this maximally concentrated Sulfuric acid * 1.8437 g/mL * 0.98 * 96.0626/98.07848 = 88.48445 g. of SO4-- ion

Dilute 50 mL of this concentrated acid via adding it into 950 mL of water and you now have 88.48445 g. of SO4-- ion in 1 Liter of diluted acid solution.

Therefore every mL of this diluted acid solution will deliver 88.48445 mg. of SO4-- ion.

Example:

Add 10 mL of this diluted acid into 18.927 Liters (5 gallons) of distilled water and you have:

10 mL * 88.48445 mg./mL of SO4-- ion = 884.8445 mg. SO4-- ion

884.8445 mg SO4-- ion ÷ 18.927 Liters = ~46.75 mg/L (ppm) of SO4-- ions in 5 gallons of water.

Add another 10 mL (for 20 mL total) and you now have ~93.5 mg/L (ppm) of SO4-- ions in 5 gallons of water.

Etc...

Note that "technically" you will actually have a tiny smidge less than 93.5 mg/L (ppm) SO4-- because of the mL of water which you have just added to your initial 5 gallons of water, increasing its volume. If you are persnickety, you can factor in compensation for this. It won't change the SO4-- concentration by very much.

CAUTION and WARNING: Always add acid into dilution water. Never add dilution water into acid.
CAUTION and WARNING #2: Always wear fully adequate and appropriate PPE and eye protection when handling concentrated acids.

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Calculating this diluted acid solutions mEq/mL acid strength:

MW of H2SO4 = 98.07848 g./mol
Density of 98% H2SO4 = 1.8437 g./mL
Charge = 2 (because H2SO4 has 2 H+ ions that it can liberate)
EQWt = 98.07848/2 = 49.03924 g./EQ (because the charge is 2)
50 mL x 1.8437 g./mL = 92.185 grams total (acid plus water)
92.185 g. x 98% = 90.3413 grams of H2SO4
90.3413 g. / 49.03924 g./EQ = 1.842225 EQ's
Final volume = 1 Liter
1.842225 EQ's / 1 Liter = 1.842225 EQ/L = 1.842225 mEq/mL
Answer = 1.842225 mEq/mL acid strength

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For a bit of mEq/mL acid strength comparison at (specifically) a targeted mash pH of 5.40:

10% Phosphoric Acid = 1.09032 mEq/mL at pH 5.40
30% Phosphoric Acid = 3.66700 mEq/mL at pH 5.40
75% Phosphoric Acid = 12.26217 mEq/mL at pH 5.40
85% Phosphoric Acid = 14.86526 mEq/mL at pH 5.40
80% Lactic Acid = 10.24646 mEq/mL at pH 5.40
88% Lactic Acid = 11.45152 mEq/mL at pH 5.40
Anhydrous Citric Acid = 12.63479 mEq/gram at pH 5.40

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Since H2SO4 (Sulfuric Acid) fully dissociates in water (whereas Phosphoric and Lactic Acids do not), the acid strength of this diluted H2SO4 solution (as outlined above) remains 1.842225 mEq/mL at any targeted mash pH (whereas Phosphoric and Lactic Acids mEq/mL acid strengths change appreciably with targeted pH). A huge bonus for computational simplicity!!!

Wow!!
Thank you Larry.
This is exactly the information I need. I'll take my time to get my head around it ( I've just had 6 of These ). So I'll battle this tomorrow.

Wow!!
Thank you Larry.
This is exactly the information I need. I'll take my time to get my head around it ( I've just had 6 of These ). So I'll battle this tomorrow.
Hopefully I've taken a lot of the battle out of it for you.

Hopefully I've taken a lot of the battle out of it for you.
You certainly have. Thank you so much.
I will order the H2SO4 - 98% today. It seems that the cheapest way to buy it is in a 1L bottle. The product is cheaper than the shipping cost! If I can't find a better way to acquire a smaller quantity I will just have to try to find other uses for it. I'm open to suggestions?

98% H2SO4 is very dangerous stuff. Use all due caution. Wear all due PPE including apron and face shield plus goggles. And due to fumes it would be best to carefully and slowly pour out the well metered 50 mL's and do the diluting outside. Stay upwind to avoid fumes. Add acid to the quenching and diluting 950 mL's of water, and not the other way around. Otherwise the acid will potentially boil the water and splash you with hot acid. I can't overemphasize the danger involved.

It will evolve a lot of heat when added to the 950 mL of distilled or deionized water. Pyrex equivalent glassware is a must. Your very best bet would seriously be to visit a University and see a Chemist and ask him/her if they would be so kind as to mix it for you under a proper exhaust hood and with proper protection(s) and glassware. The university will likely have a very high purity grade of 98% H2SO4 in their lab(s). Let them know that this is for a food application aforehand. Or seek to purchase very high purity 2N (2 Normal) H2SO4, which will be 2 mEq/mL in strength as opposed to 1.8422. Then no dilution will be required, but the SO4 delivery will be non-linearly higher and will need to be re-calculated.

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I very quickly roughed in (I.E., loosely ballparked) that adding 10 mL of 2N H2SO4 to 5 gallons of water will contribute about 52.5 mg/L (ppm) of H2SO4 to the 5 gallons. Or it will contribute about 50 mg/L (ppm) SO4 if added into 20 Liters of water. The latter making things a lot easier to remember.

But seek out a good chemist to verify all of this first. As Ronald Reagan once said: "Trust, but verify".

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2N Sulfuric Acid should likely be quite purchasable. Buying 1L of 2 Normal H2SO4 (of the highest possible purity) is the best bet hands down from a safety as well as long term storage perspective, and it should last a long time. That plus the ease of assuming ~50 ppm SO4 contributed for every 10 mL of the 2N solution added to 20L of water being a big winner.

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You certainly have. Thank you so much.
I will order the H2SO4 - 98% today. It seems that the cheapest way to buy it is in a 1L bottle. The product is cheaper than the shipping cost! If I can't find a better way to acquire a smaller quantity I will just have to try to find other uses for it. I'm open to suggestions?
Are you actually aware of what type of chemical you are ordering there? This stuff is REALLY DANGEROUS. I mean it.

I've dropped some single drops on a kitchen towel once, instantly gone. It's that corrosive. It burns through everything in fractions of a second. The fumes as well.

I'm pretty surprised that you can actually buy this stuff without showing any certificate in your country.

I don't believe that the average Joe/Joesette in the USA can purchase high purity 98% concentrated Sulfuric Acid.

I agree with @Miraculix. Don't mess with full strength sulfuric acid. Besides the"obvious" risk of dissolving things by accidental contact, you can damage your lungs over time by breathing the fumes. You can even damage your teeth by breathing the fumes.

2N Sulfuric Acid should likely be quite purchasable. Buying 1L of 2 Normal H2SO4 (of the highest possible purity) is the best bet hands down from a safety as well as long term storage perspective, and it should last a long time. That plus the ease of assuming ~50 ppm SO4 contributed for every 10 mL of the 2N solution added to 20L of water being a big winner.

Wouldn't H2SO3 be a less harmful option as well?

Per Wikipedia:
"There is no evidence that sulfurous acid exists in solution, but the molecule has been detected in the gas phase."

That plus lots of negatives involving hazardous decomposition products...

I will order the H2SO4 - 98% today.
( I'm not a chemist)
That stuff is seriously dangerous, especially in "unskilled hands."
Is this really worth it?

I'm echoing what @Silver_Is_Money, @VikeMan, and @Miraculix already said about handling this product. Even in 2N strength, there is nothing to be casual about.

It's crazy just anyone can buy it like that and get it shipped (through FedEx Ground). Man, if this thing leaks or the package gets pierced or mangled... or ends up in the wrong hands...

I'm surprised it comes in an HDPE bottle. Must be for shipping purposes only, perhaps safer than shipping a glass bottle. But, you can't keep it stored in that plastic bottle, (see Note). That means you'll need to transfer that dangerous 98% Sulphuric Acid to a glass bottle made for strong acid storage, including a lid that's also suitable, not the old vinegar bottle from the kitchen.

Note:
* Indeed, the plastic bottle it comes in gets compromised by its content (not surprisingly):
"plastic bottle darkened after about 6 months, became black on inside surface. I now pour it into a glass bottle i have for storage."​
"The lid is not very secure. Do not tilt while carrying. Do not cary by holding the lid! Mine squirted out on my hand [...]"​

If phrasing and spelling errors in those comments are an indication of the typical audience products like these are sold to, it becomes even more alarming.

Wow, you guys seem to be going to a lot of trouble to fix a simple problem. The amount of SMB or KMB needed to dechlorinate 20L of tap water is contained in about a quarter of a Campden tablet. The amount of of Na or K is negligible. It's within the uncertainty of the water analysis. The taste effect of that amount of Na is undetectable. Some brewers add much more SMB or KMB in the mash or later to reduce oxidation. See General 5 | Bru'n Water. Martin says that one tablet per 75 L (~9 mg per liter), "...leave(s) residual concentrations of about 3 ppm potassium or 2 ppm sodium ... and 8 ppm sulfate and 3 ppm chloride. These ion contributions are relatively insignificant and can be ignored in practice."

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After crunching better numbers it turns out that 10 mL of 2N H2SO4 will contribute the following as to SO4-- ion:

10 mL added to 5 gallons of water = 50.75 ppm SO4
10 mL added to 20L of water = 48.03 ppm SO4

Both of these are close enough for all practical purposes to 50 ppm SO4 to just remember it as 50 ppm.

I was somewhat apprehensive about acquiring this 98% concentration and have already decided not to. Especially since it would be a much greater volume than I could ever use. And yes, I would need to provide the appropriate documentation in order to purchase it as Aus law is very strict in regards to dangerous materials. I may even be required to sign off for 2N H2So4.

2N Sulfuric Acid should likely be quite purchasable. Buying 1L of 2 Normal H2SO4 (of the highest possible purity) is the best bet hands down from a safety as well as long term storage perspective, and it should last a long time. That plus the ease of assuming ~50 ppm SO4 contributed for every 10 mL of the 2N solution added to 20L of water being a big winner.

I will be taking your advice Larry, and thank you for all of the work you have done. All very useful information.

One more question:
Am I right in making the calculated assumption that 2 milliequivalents per ml constitutes a 5.539% solution, and could this value be added to the Bru'n Water calculator to safely determine So4 levels and the adjusted pH of the water?

Again, thank you all for your consideration.

It's closer to being roughly a 9.3% solution.

For those wondering, 1M (one molar) H2SO4 and 2N (two normal) H2SO4 solutions are the exact same thing.

It's closer to being roughly a 9.3% solution.
Of course, in saying this, there are three means of achieving percent here:

1) Volume to Volume
2) Weight to Volume
3) Weight to Weight

For those who are truly persnickety:

A 2.082N solution of H2SO4 should deliver nigh-on precisely 100 mg/mL of SO4-- ion.

694 mL of 3N H2SO4 when made up (diluted) into pure water to a final volume of 1000 mL should yield 1 Liter of 2.082N H2SO4 if I've calculated correctly.

As always: Trust but verify!!! I make mistakes!!!

WARNING & CAUTION: All due safety precautions and PPE as have been discussed above apply here also.

2.082N H2S4 will have an acid strength of 2.082 mEq/mL.

For those wondering, 2.82M HCl (which is also 2.82N, and 2.82 mEq/mL) delivers 100 mg/mL of Cl- ions.

This thread is terrifying for so many reasons: dissolving towels, potential loss of teeth, general chem mathematics!
But +1 on @mosquitofeet: I use .025 grams Potassium Metabisulfite to dechloraminate one gallon tap water. Whatever reaction products it might add are so negligible that I'm not sure why more needs to be done, not least mess with a dangerous chemical.
That said, I think the OP was interested in adding brewing salts but didn't have anything but campion tabs on hand? It's pretty easy to get things like kosher/sea salt & Epsom salts at least at the local market/pharmacy. Wort also has plenty of minerals and you can forego any water additions in a pinch if need be and still make a decent beer.

Wort also has plenty of minerals and you can forego any water additions in a pinch if need be and still make a decent beer.
Totally agree! You can brew with distilled water with nothing in it and there is plenty of the nutrients the yeast need in an all-malt wort. But there are plenty of beer styles that can be made better with judicious water adjustments to make them taste better. I do recommend that all brewers should adjust their water.

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