Servomyces is a nutritional yeast supplement (GMO free) that was originally developed for German brewers by Weihenstephan and the Munich University. It conforms to the restrictions of Reinheitsgebot. Servomyces enables any yeast strain's ability to incorporate essential nutrients into its cellular structure. Tested in breweries around the world, it has been proven to:

* Cut down fermentation time
* Increase flocculation
* Greatly reduce harsh sulfur notes
* Improve the health and viability of yeast
* Reduce levels of diacetyl at the end of primary fermentation
* Produce faster, more complete attenuations
* Increase yeast production for a better harvest
* Improve the quality of the finished product

Recent developments have made Servomyces available to homebrewers and home winemakers. Each retail packet contains 6 capsules, which can each be used for a 5-gallon (20 to 25L) batch of beer, wine, mead or cider. The instructions are listed below:

Add 1 capsule 10 minutes prior to the end of the boil.

OR, If your fermentation does not require a boil, open the capsule and pour in the Servomyces, since the capsule casing requires boiling to melt.

Only one capsule is required per 5-gallon (20 to 25 L) batch.

Servomyces can be used in all fermentations, including beer, wine, cider and mead.

Link: White Labs nutrient FAQ questions.