"Negodki" wrote in message ...
snip
To make up a 10% solution, mix 25 grams potassium metabisulphite powder or
crystals with 250 ml. (about a cup) of warm water. Stir it well, to insure
all the powder is dissolved. Distilled is best, but if your tap water is
drinkable it will do. Store it in a dark glass or white plastic jar with a
good lid. It will last indefinitely. One teaspoon (50 ml) of this solution
is equivalent to one campden tablet, and is the amount you should normally
add per gallon of must. If you use a graduated syringe, you can make
accurate measurements for smaller containers.

This is nitpicking, I know - it doesn't sound like you were shooting
for accuracy here - but for a 10% solution you want 25 grams in 225 ml
of water, not 250.

- Mark W.