It has long been recognised in animal and human nutrition that certain trace minerals have a vital, life-giving role and that their absence, or sub-optimal inclusion in diets, can have a mulitiplicity of deleterious effects. Supplementation of these trace elements or micro-nutrients by way of direct addition of the element or salt thereof can relieve these symptoms. However it is now generally recognised that the manifestation of this preparation can have an important effect on the digestibility and efficacy of these micro-nutrients. For example, weight for weight, minerals, when part of a biological preparation, have been proven to more efficacious than their salts. This has led to a great deal of commercial development in the sale of mineral yeasts for human and animal nutrition. The question is; can such preparations be used and are they efficacious in fermentation and yeast trace nutrition. Can they be used to substitute for mineral salts and what is the effect on yeast performance and beer flavour? A number of experiments have been carried out, both in the laboratory and in full-scale brewery volumes using a yeast containing large concentrations of zinc. The zinc is not admixed to the yeast but is fed to the yeast during growth and becomes incorporated by the yeast cells. Levels of incorporated zinc of up to 70,000 ppm have been produced commercially. The yeast is still living and capable of alcoholic fermentation. When such a yeast is added to beer wort, in some inactivated form, laboratory experiments and practical brewery trials reveal that the biological mineral yeast preparation, trade marked Servomyces, has a greater effect on fermentation and fermentation velocity than an equivalent mineral salt preparation. Moreover, its use in one brewery's yeast propagation system revealed that 50% more yeast cells could be produced under a given set of parameters. The beers produced with such preparations also attract objective flavour descriptions by the breweries' personnel, which suggest that they are smoother and less harsh. This may have scientific, technological and commercial significance for those breweries, which wish to pursue a minimal additive beer or where the addition of mineral salts is forbidden. Work is continuing in investigating the incorporation of other trace minerals and elements for the alleviation of specific stress related brewing problems such as associated with very high-gravity brewing regimes. The use of such preparations, in the production of alcoholic beverages, is covered by various international patents, assigned to Danstar Ferment A. G.