Potassium metabisulfite math help

[Sammyk]

Can someone help? I would like to mix my kmeta in water and then add the correct amount to each gallon of wine. We age in 1 gallon carboys. So if I were to mix say 8 oz of water how much kmeta would I put in 8 oz and how much would of the solution would I add to each gallon?

 

[Honda88]

1/8 tsp per gallon is what my bottle says, so I would just take a cup of water and mix 1/8 tsp then add to your gallon carboy....

 

[Rodnboro]

I just read a post in another forum and they mixed 2 tsp in 20 oz. of water and added 15 ml. (1/2 oz.) per gallon.

 

[Yooper]

I've seen a "recipe" somewhere where you mix up the solution and use 1 teaspoon of that per gallon, but I can't find it now. A search on google may help, but I didn't find it with a quick look.

I normally use 1/4 teaspoon per 5 gallons (NOT 1/8 teaspoon per gallon!) for approximately 50 ppm of free SO2. I mix that up in some water, and rack the wine into it. I hope that helps.

I did see this on Jack Keller's site:


Calculation of Sulfur Dioxide (SO2)

Potassium metabisulfite, 1 gram = 150 ppm in 1 gallon, 30 ppm in 5 gallons
Potassium metabisulfite, ¼ teaspoon = 225 ppm in 1 gallon, 45 ppm in 5 gallons
Potassium metabisulfite, 1½ tablespoon to 1 gallon water makes ½% solution for washing equipment
Potassium metabisulfite, 2 oz. to 1 quart water makes 5% solution for sterilizing must (1 teaspoon solution per gallon of must)
1 Campden tablet contains 0.55 grams potassium metabisulfite, yielding 75 ppm SO2 to one gallon of must or wine

 

[Sammyk]

I did do a Google search and could not find anything. Does this sound right? Mix 2 tsp in 20 oz. of water and added 15 ml. (1/2 oz.) per gallon?

 

[Honda88]

yea my bottle says to add 100ppm its crosby and baker, maybe ill add less in the future, it seemed to work fine even adding that much before the ferment...

 

[Yooper]

yea my bottle says to add 100ppm its crosby and baker, maybe ill add less in the future, it seemed to work fine even adding that much before the ferment...

That might be ok to sanitize must but it sure is an awful lot of sulfites otherwise, and may be perceptible in the taste. Of course, it does dissipate with time, but I think that would be enough to stress wine yeast and impact flavor a bit. I really like to use a minimum of sulfites, mostly as an antioxidant and preservative for aging wines.