Alcohol School: Tips to control contamination

By Lisa Gibson | September 11, 2019

Francois van Zyl, director of technical services for Lallemand Biofuels & Distilled Spirits, told his audience at The Alcohol School Sept. 11 that identifying contamination in yeast can be as easy as using a fluorescent microscope. The annual cost related to contamination can exceed $5 million, he said. “How many microscopes can you buy with $5 million?” It justifies basic monitoring, he said.

Lallemand’s Alcohol School is being held Sept. 9-13 at Intercontinental Montreal in Montreal, Quebec. The sessions Sept. 11 were held at National Research Council Canada, with tours of Lallemand’s research lab spaces on site.

“Time is money,” van Zyl said. The longer a contamination sits, the more money it costs. Contamination can also be detected through nonmechanical means, such as pH curve and titration of total acidity. 

He emphasized managing the four Ts: time, titration, temperature and turbulence. “Ninety-eight percent of the time, people do not follow this rule,” he said. Cleaning takes time but, done well, can be efficient. Generally, warm detergent solutions clean better than cold solutions. For titrations, stronger solutions do clean better, van Zyl said. There should never be issues with turbulence, he said. Pipes require a minimum cleaning solution velocity of five feet per second of effective cleaning.

To troubleshoot contamination events, real-time tests are required, he said. Simple techniques can include a sample test, looking for step changes. van Zyl emphasized more than once that it’s crucial to understand the process.

Concentrate on the four Ts, document all changes made, remove dirt and sanitize, van Zyl said.

van Zyl also said he is a supporter of mechanical solutions. “You can resolve a lot of your own costs just by paying attention to detail.”