P-36
Barometric pressure correction for measured CO(2) concentration.
Henry's Law is used a basis to determine the CO(2) content in carbonated beverages. The procedure requires measuring the temperature and pressure of a sample of the beverage in a closed container that has been agitated. The pressure used to correlate concentration in the Henry's Law relationship is absolute pressure whereas pressure measurements in the lab and plant are gauge pressure. While this is normally not a problem, errors are introduced by variations in the barometric pressure that change the relationship between absolute and gauge pressure. Weather changes as well as the local elevation above sea level cause barometric pressure changes. This poster describes and quantifies errors in CO(2) concentration due to barometric pressure changes. A simple correction method is presented.
Jim Larson began his brewing career in 1972 working on the development of the Uni-Tank at the Rainier Brewery in Seattle, Washington. He later worked in brewing production and engineering with Rainier and the G. Heileman Brewing Company at breweries in LaCrosse, Wisconsin, Seattle and Baltimore. In 1996 he joined the Siebel Institute of Technology where he taught in the brewing science and engineering courses, did contract research projects and served as Director of Education. He joined Alltech, Inc. in February 2000 as Technical Sales Representative, working with breweries and distilleries. Jim earned his M.S. degree in chemical engineering at the University of Washington. Joe Power has a Ph.D. in biology from the University of California, Santa Barbara. He started in brewing at the Peter Hand brewery in Chicago, working in quality control and in production as assistant brewmaster. In 1978 when the brewery closed, he joined the research department of J.E. Siebel Sons' Co. and headed research on brewing products. He also did technical service work and taught brewing science, especially enzymes, fermentation, microbiology, quality control and water chemistry. After the Siebel Institute reduced operations he joined Alltech, Inc. in 2000 as technical director for brewing and fermentation.