I use White Labs nutrient. Here's what they have to say:Well, from what I have seen, it depends on the og of the beer. I have seen upwards of 1 tsp for high gravity beers (around 1.1+) per gallon. Ultra-high gravity beers need more nutrients, so that has worked for me in the past. I usually don't add nutrients to normal strength (~5% and under) because there is enough in the malt available to the yeast.
It sounds like 1/2 tsp. is adequate for 5 gallons, at least as far as WLN1000 is concerned. I'm not sure about other types of nutrient.Give your beer, mead, wine, or yeast culture an energy boost! Use 1/2 teaspoon per 5 gallons of beer. Store at 40-70F. Add to boil in last 5 min., or boil separately for 5 min. Shelf life is nine months from date of preparation on vial. White Labs Nutrient is comprised mostly of amino acids, which are building blocks for proteins. It doesn't speed up a fermentation much, but it does make for healthier yeast. It can be used with Servomyces.
White Labs Yeast Nutrient is a complex blend of nitrogen, vitamins, and co-factors. We designed it specifically for White Labs Yeast to increase vitality and viability in our yeast propagations. It is different from other nutrients in the market is because of the increased amount and variety of amino acids and cofactors. This increases the rate of metabolism, which results in faster fermentation and greater yeast viability. I t is an affordable way to increase the success of your brew. Our brewers have found it very beneficial for first generation, stuck fermentation and high gravity beers. Yeast nutrient can also be helpful when brewing high gravity beers. For commercial breweries, we package it in dry form in vials that are re-measured for 5 barrels. Nutrient is good for every generation and a must for beers above 1.070 SG or 17 Plato.