Originally Posted by wikipedia.org
The powder is difficult to use for small batches of wine or beer. This is because it inhibits the action of all yeasts; wine yeasts are just more resistant than other microorganisms. If too much potassium metabisulfite is added it will result in a 'stuck' fermentation. The typical amount is around 1/4-1/2 teaspoon per 5 gallons. So for batches smaller than this Campden tablets are normally used.
But what that is talking about is adding the potassium metabisulphite in with the wine or beer as an additive. I'm sure rinsing with it would be fine since I doubt it would kill the yeast with such a small quantity of it.