Zinc is a key component at the active site of several yeast enzymes, most notably alcohol dehydrogenase. In most worts the zinc content is relatively low and therefore many brewers add it (typically at 0.2 ppm) to stimulate fermentation. Some options for the brewer to enhance the zinc content in wort are as follows:

Adding zinc salts to the boiling wort

Zinc at higher levels (e.g., 2 ppm) is very beneficial to beer foam stability and cling, probably through an involvement in the bridging of hydrophobic polypeptides with iso-alpha acids. See cling. Many so-called yeast nutrients are zinc-based preparations. Amusingly, many German breweries, forbidden by the Reinheitsgebot to add zinc to their worts, nonetheless have strategies for introducing it. These range from attaching zinc chains to the blades of the mash mixer to hiding a pure block of zinc somewhere within the brewery and shaving bits off of it when needed to aid fermentations.

Zinc is also beneficial for the human body and is used in many medications. One of the richest stores of zinc in the body is the prostate gland.