Nineteen different materials were added to albumin foam in different experiments to investigate their ability to modulate the volume of aerated protein foam generated at a given air flow rate and pH. Activation of that foam may be desirable when harvesting proteins from a recovered protein-water solution using a foam fractionation process. It may also be useful as an on-line adjunct in a fermentation process to help separate desired proteins at certain running times. Inorganic phosphate and nitrate salts used as temporary activators could be incorporated into the bioreactor growing cells following activation, offering the advantage of protein “salting out” at selected times. Inhibition of that foam is desirable to minimize foam within a fermentation process in order to maximize the working space of the liquid broth. Use of natural organic materials (which can be biodegraded and incorporated into the growing organism) may circumvent oxygen transfer resistances resulting from the use of standard silicone anti-foams. It was observed that ginger and glutamic acid are strong foam activators while grape tannin and potato starch are significant foam inhibitors. These results may be relevant to food applications and activated sludge processes as well as bioprocess control and protein separation technologies.