brewers yeast in health food store and in grocery store are the dead/spent yeast and will not metabolize sugar into carbon dioxide nor into alcohol. A quick way to tell is if it comes in big jars, or even in small jars, its not the one you want. The brewer's yeast has to be obtained from homebrew shops... and usually sold in small quantities like bakers yeast you can buy at grocery store. These brewers yeast would have recommendation for use as pilsner, lager, ale, stout, wine or champagne making.

Just in case you want to try. Use regular bread yeast. 1/8tsp is all is needed. Anymore and you might end up with a drink that has yeasty taste and flavor.

I just had a problem with fizzyness of my drink.

If I get it right, this is so much cheaper... Husband of my mother's best friend used to make homebrew root beer years ago (40+ yrs ago). And every once in a while his 5 gallon jug would turn into a geyser inside a front hall closet. It smelled like root beer just not pretty and sticky everywhere...