Silicone Oils

Food-grade silicone fluids in food and beverage are polydimethylsiloxane (PDMS) antifoam emulsions that collapse existing foam and suppress new foam during processing. PDMS has a very low surface tension, so it spreads at the air/liquid interface and ruptures the thin films that hold bubbles together. It is supplied as a 10-50% active emulsion and works at low addition levels, which is why a small drum covers a large production volume.

A defoamer knocks down foam that has already formed; an antifoam added up front stops it from building. A silicone emulsion does both, which is its edge over organic defoamers. The trade-off is dose discipline: silicone is so effective that an overdose can carry into the finished product and flatten foam you want, such as a beer head or whipped-dessert aeration. Dose to the minimum that controls process foam, and control the point of addition.

Typical duties are foam control in fermentation, vacuum evaporation and concentration, frying oils, and high-speed bottling and filling. Polydimethylsiloxane is permitted as a defoaming agent under food-additive regulations (for example 21 CFR 173.340 in the United States and E900 in the EU); confirm regulatory status for your application and jurisdiction. Match the emulsion's active level and viscosity to your process, and run a small trial to set the dose before scaling up.

• Foam control in fermentation — brewing, distilling, and biotech feedstocks
• Defoaming in vacuum evaporation and concentration of juices, dairy, and extracts
• Foam suppression in frying oils and high-temperature processing
• Carry-over control on high-speed bottling, canning, and filling lines
• General process antifoam for CIP and food-plant wastewater streams

• Polydimethylsiloxane (dimethicone) — PubChem