De-chlorination substance

[peteru]

So, vitamin C will end up with DHA and gasses (which will presumably come out of solution) as a byproduct, whereas sodium met will give you salt and sulphuric acid. Me guess that DHA might be slightly more desirable for the subsequent reactions.

Ergo vitamin C "wins"

 

[Ducatiboy stu]

Stolen from the internet

Removing chloramines from water[SIZE=small][edit][/SIZE]

Chloramines should be removed from water for dialysis, aquariums, hydroponic applications, and homebrewing beer. Chloramines can interfere with dialysis, can hurt aquatic animals, and can give homebrewed beer a medicinal taste by forming chlorophenols. In hydroponic applications, it will stunt the growth of plants.[15]
When a chemical or biological process that changes the chemistry of chloramines is used, it falls under reductive dechlorination. Other techniques use physical—not chemical—methods for removing chloramines.[citation needed]

Dialysis[SIZE=small][edit][/SIZE]
Chloramine must be removed from the water prior to use in kidney dialysis machines, as it would come in contact with the bloodstream across a permeable membrane. However, since chloramine is neutralized by the digestive process, kidney dialysis patients can still safely drink chloramine-treated water.[16]

Ultraviolet light[SIZE=small][edit][/SIZE]

The use of ultraviolet (UV) light for chlorine or chloramine removal is an established technology that has been widely accepted in pharmaceutical, beverage, and dialysis applications.[17] UV is also used for disinfection at aquatic facilities.

Superchlorination[SIZE=small][edit][/SIZE]
Chloramine can be removed from tap water by treatment with superchlorination (10 ppm or more of free chlorine, such as from a dose of sodium hypochlorite bleach or pool sanitizer) while maintaining a pH of about 7 (such as from a dose of hydrochloric acid). Hypochlorous acid from the free chlorine strips the ammonia from the chloramine, and the ammonia outgasses from the surface of the bulk water. This process takes about 24 hours for normal tap water concentrations of a few ppm of chloramine. Residual free chlorine can then be removed by exposure to bright sunlight for about 4 hours.[citation needed]

Ascorbic acid and sodium ascorbate[SIZE=small][edit][/SIZE]
Ascorbic acid and sodium ascorbate completely neutralize both chlorine and chloramine, but degrade in a day or two, which makes them usable only for short-term applications. SFPUC determined that 1000 mg of Vitamin C tablets, crushed and mixed in with bath water, completely remove chloramine in a medium-size bathtub without significantly depressing pH.[18]

Activated carbon[SIZE=small][edit][/SIZE]
Activated carbon has been used for chloramine removal long before catalytic carbon became available; standard activated carbon requires a very long contact time, which means a large volume of carbon is needed. For thorough removal, up to four times the contact time of catalytic carbon may be required.
Most dialysis units now depend on granular activated carbon (GAC) filters, two of which should be placed in series so that chloramine breakthrough can be detected after the first one, before the second one fails.[19] Additionally, sodium metabisulfite injection may be used in certain circumstances.[20]

Campden tablets[SIZE=small][edit][/SIZE]
Home brewers use reducing agents such as sodium metabisulfite or potassium metabisulfite (both proprietary sold as Campden tablets) to remove chloramine from brewing fermented beverages. However, residual sodium can cause off flavors in beer[21] sopotassium metabisulfite is preferred.

Sodium thiosulfate[SIZE=small][edit][/SIZE]
Sodium thiosulfate is used to dechlorinate tap water for aquariums or treat effluent from waste water treatments prior to release into rivers. The reduction reaction is analogous to the iodine reduction reaction. Treatment of tap water requires between 0.1 grams and 0.3 grams of pentahydrated (crystalline) sodium thiosulfate per 10 liters of water. Many animals are sensitive to chloramine, and it must be removed from water given to many animals in zoos.

Other methods[SIZE=small][edit][/SIZE]
Chloramine, like chlorine, can be removed by boiling and aging. However, time required to remove chloramine is much longer than that of chlorine. The time required to remove half of the chloramine (half-life) from 10 gallons of water by boiling is 26.6 hours, whereas the half-life of free chlorine in boiling 10 gallons of water is only 1.8 hours.[22]

 

[Adr_0]

So, vitamin C will end up with DHA and gasses (which will presumably come out of solution) as a byproduct, whereas sodium met will give you salt and sulphuric acid. Me guess that DHA might be slightly more desirable for the subsequent reactions.

Ergo vitamin C "wins"

Homebrewers win - lots of options. As MHB said, sodium met works faster. Keep in mind HCl will also slightly acidify your water, and salt is arguably very useful for maltier beers.

I've used vitamin C for the last 12-18mths and it works extremely well. I forgot to add to sparge water and got horrible chlorophenols - lots of chloramine in water here - so it's definitely effective in a 2-3x excess.

On the other hand, I've been burnt using sodium met - because I didn't use enough (didn't do the 2-3x excess). Rather than leaving too much salt I would actually argue that too much sodium met will leave you with sodium sulphite, or if you have O2 through your system, sodium sulphate. This would be quite noticeable. They are basically what's left once chlorine gets neutralised and you have leftover sodium met sitting in the water.

I'm looking at moving to a 50:50wt% mix on sodium met and ascorbic acid for some extra O2 scavengabilitynessment... But that's a story far another day.

 

[Lyrebird_Cycles]

So, vitamin C will end up with DHA and gasses (which will presumably come out of solution) as a byproduct, whereas sodium met will give you salt and sulphuric acid. Me guess that DHA might be slightly more desirable for the subsequent reactions.

Ergo vitamin C "wins"

I would argue that DHA is less desirable for subsequent reactions as it promotes oxidation due to its functionality as an electron transporter.

I can't see a few ppm of sulphate being much of a problem. If the countervailing cation is a problem you could always use calcium bisulphite instead of PMS / SMS .

That being said, I add 25 mg/l ascorbic to Melbourne water with no discernable ill effects, even in very pale beers with only "noble" hop adds.

 

[Adr_0]

Alright let me redo that sucker. I should probably be scolded or at least fired for rushing things and ignoring basics like which one donates hydrogen/behaves like an acid.

So firstly, sodium met:

Na2S2O5 + H2O >> 2NaHSO3 (sodium bisulphite, ie the 1000L sitting in front of me at work)
Then:
2NaHSO3 + 2HOCl >> 2HCl + Na2SO4 + H2SO4
>unreacted SBS will bond with any O2 to form sodium sulphate Na2SO4, and sulphuric acid H2SO4
>products are basically acids and sodium sulphate

For chloramine, water would be needed to donate H+ unlike normal chlorine:
2NaHSO3 + 2NH2Cl + 2H2O >> NaSO4 + H2SO4 + 2Cl + 2NH4
>ammonium chloride is produced, good for yeast
>still have sodium sulphate, slightly less acid

For ascorbic acid:

Dissociating in water
C6H8O6 + H2O >> C6H7O6- + H3O+

then with chlorine:
C6H7O6 + H3O + HOCl >> C6H6O6 + 2H20 + HCl

And for chloramine:
C6H7O6 + H3O + NH2Cl >> C6H6O6 + H2O + NH4 + Cl
>> basically the byproduct if this is ammonium chloride
>>if there is any excess past the requirement of the chloramine, the H3O excess will react with O2 in a 2:1 to make water

Whenever chloramine is involved, NH4(+) is produced which will likely form salts with Chloride (-). Not sure either way on DHA. Sorry about the earlier dodgy post.

 

[Adr_0]

I would argue that DHA is less desirable for subsequent reactions as it promotes oxidation due to its functionality as an electron transporter.

I can't see a few ppm of sulphate being much of a problem. If the countervailing cation is a problem you could always use calcium bisulphite instead of PMS / SMS .

That being said, I add 25 mg/l ascorbic to Melbourne water with no discernable ill effects, even in very pale beers with only "noble" hop adds.

I guess, but if you have ascorbic acid in excess - with some left over after chlorine/chloramine is neutralised - you have a pretty effective pair (the ascorbate ion and hydronium ion) for neutralising O2. Vitamin C is known as a a good O2 scavenger but I'm not sure if sodium ascorbate is preferred over ascorbic acid. I agree that DHAA would not be much use as an oxygen scavenger but I'm not sure under what conditions it would go back to the ascorbate ion.

 

[MHB]

Don't be frightened of the HCl and the likes that are ending up in the brew. We are talking very small amounts 2-4ppm when we make salt additions we are adding (well it varies) but a minimum of 10 times as much, often 50 times.
The relatively small amount of extra ions in solution probably wont matter much either way, but the Chlorine/Chloramine will.
Mark

 

[Adr_0]

Don't be frightened of the HCl and the likes that are ending up in the brew. We are talking very small amounts 2-4ppm when we make salt additions we are adding (well it varies) but a minimum of 10 times as much, often 50 times.
The relatively small amount of extra ions in solution probably wont matter much either way, but the Chlorine/Chloramine will.
Mark

That's gotta be pretty close to the most wisest advice I've heard on water.