potassium metabisulfte powder and Chlorine

[Arbe0]

I have seen information on campden tablets but they have fillers. If I want to use the power Potassium Metabisulfate instead of the campden tablets to dissipate the chlorine / chlorinime how much would I use? With all the conflicting information I have seen I think I would go with .025 grams for 1 gallon of water. To make it simpler, maybe for 10 gallons I would need .25 grams of potassium metabisulfate powder. I need all your smart guys to give me an idea on if this sounds right.

 

[seatazzz]

Both the tablets and the powder are super cheap. And if you go a little bit heavy it won't hurt your beer. I used to use the tablets but got tired of crushing them, so switched to the powder. I use about 1/8 tsp for a 5 gallon batch and it does the trick. Of course it depends on how much chlorine is in your tap water to begin with; do you have a water report? Does your tap water smell bleachy?

 

[Arbe0]

It seems all depends of what is measured. 1tsp of salt = 5.9 grams, while 1 tsp of granulated sugar = 4.8 grams, and 1 tsp of baking soda = 3.4 grams. Really not much of a difference, I guess. If I go with 1/4 tsp for 10 gallons that would be around 1.475 grams as salt, 1.2 grams as sugar, and .85 grams as baking soda.
not really much difference so I guess I would go with the most just to be ok with it which would be 1.4 grams for 10 gallons or .14 grams per gallon. Does this all sound right?

 

[IslandLizard]

Not sure where I got the information from originally, but AFAIK, 1/4 teaspoon of K-Meta (or Na-Meta) will treat 20 gallons of water to remove all chlorine and/or chloramines.

That would mean 1/4 of 1/4 of a teaspoon = 1/16 of a teaspoon, will treat 5 gallons of water.
So really, it's literally a pinch ! (being 1/16 teaspoon).

And yes, Campden tablets have a binder in them, not sure how much.

 

[Arbe0]

found a site that says " Campden tablets typically contain 0.44 g each of sodium metabisulfite (plus filler) "
Campden tablets (happyherbalist.com) So .44 grams for 20 gallons, .22 for 10 gallons or .044 grams per gallon.

 

[dmaxweb]

When I was in college I worked at a large tropical fish hatchery. We would mix batches of potassium metabisulfate (same as photo developing fixer) and water and put the solution in squeeze bottles. We used it to remove chlorine from the water. When everything around you was wet like a brewery with fish, using dry powder was a no go. A measuring spoon of the solution to 500 gallon tanks did the job. Bottles of the solution were always at hand.
Should be easy enough to back into the ratio of the mix and how much to use per gallon.

 

[dmaxweb]

If I'm doing my math correct on a Monday morning -

Let's say I disolve 6g Potassium Metabisulfate in 240 mil water. That solution is .025g /ml. 1 ml of the solution treats 1 gallon of water. Easy to remember, easy to dispense using a syringe, and no weighing on brew day. Plus eliminates scale error trying to weigh grams to decimals.

 

[IslandLizard]

Let's say I disolve 6g Potassium Metabisulfate in 240 mil water. That solution is .025g /ml. 1 ml of the solution treats 1 gallon of water. Easy to remember, easy to dispense using a syringe, and no weighing on brew day.

A solution of sulphites in presence of oxygen will oxidize over time, turning it into a sulphate solution.

Plus eliminates scale error trying to weigh grams to decimals.

To remove chlorine and chloramines in water, dosage is not very critical. 1/16 teaspoon (a 1/4 of a 1/4 teaspoon measure) of sulphite powder will treat 5 gallons. Even a double or quadruple dosage won't do any harm.
You could weigh it out once* and see how much it is, and use that reference for the future.

* You'd need a scale that weighs down to 1/100 of a gram, good for weighing all your water minerals. They run around $15.