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Karl Siebert

Karl Siebert

Emeritus

129 Food Research Lab, Geneva, NY 14456
(315) 787-2299

I worked in the brewing industry for 18 years before I became an academic, holding positions from Research Associate to Director of Research (the last 8 years) at the Stroh Brewery Co. in Detroit. I joined Cornell at the Geneva Experiment Station in 1990 as a Full Professor. I served as Chair of the Food Science & Technology Dept. for the first five years (two terms). Since then I have mainly been engaged in research with some teaching and extension; my current effort distribution officially includes research, teaching and extension. I teach the brewing part of FD SC 4300 (Understanding Wine and Beer) each spring and I teach FD SC 6080 (Chemometric Methods in Food Science) in the Fall of alternate years.

Research Focus

In terms of disciplines, my program is spread across food chemistry, food microbiology and sensory analysis and it is largely tied together with chemometrics (the application of multivariate math and statistics). The focus of the chemistry part of the program is largely on the manner in which macromolecules interact with small molecules to produce phenomena that people can directly perceive. This includes interactions of proline-rich proteins with polyphenols that produce visible turbidity in beverages and astringency in the mouth, interactions of proteins with hop bitter compounds that are involved in beer foam and gushing (uncontrolled overfoaming upon opening a container), and binding of flavor compounds by proteins and other macromolecules. I am also interested in how the molecular properties of organic compounds determine their flavor intensity (perception thresholds) and how the amino acid composition of proteins determines their physicochemical and functional properties. In the microbiology area I am interested in a number of mathematical approaches to microbiological problems. This has included work in simulation modeling of the microbial sampling of liquids, modeling how the molecular properties of organic acids result in different degrees of inhibition of different species of bacteria, and the use of pattern recognition approaches for characterizing and identifying bacteria. In the sensory area, in addition to several previously mentioned items, my group has pioneered the use of proper sensory tests (for determining perception thresholds, estimating haze intensity and describing appearance) to observe the effects of sample properties (solution color and particle size and concentration) and viewing conditions (illumination intensity and background contrast) on human visual response to turbidity. In terms of commodities my program is concentrated in beverage technology, particularly brewing, but also including fruit juice, wine, tea and coffee. Work has included fundamental studies of particle formation in beverages, mechanisms of action of various haze stabilization approaches and analytical approaches to measuring haze-active constituents.

Outreach and Extension Focus

I am responsible for Cornell's brewing extension program. I present extension workshops and short courses on brewing topics. Occasionally I respond to contacts from media or correspond with media on brewing or beverage related topics. Beer brewing and brewing science.

I make presentations on producing alcohol from grains in distillation workshops.

I train and advise students/faculty members from my department, and occasionally those from other departments, on statistical experiment design and chemometrics/ multivariate data analysis. I respond to information requests from industry in NY and beyond.

Teaching Focus

I teach the brewing part of the course FDSC4300 Understanding Wine and Beer each spring.

I teach the graduate course FDSC6080 Chemometrics in Food Science in alternate years in the fall semester. Chemometrics is the application of statistical and mathematical methods as well as the principles of good measurement science to efficiently extract useful information from chemical data. It has broad application across many disciplines and this is reflected in the attendees.

Awards and Honors

  • Award of Merit (2011) Master Brewers Association of the Americas
  • Award of Distinction (1999) American Society of Brewing Chemists

Selected Publications

Journal Publications

Book Chapters

  • Siebert, K. J. (2009). Haze in Beverages. p. 53-86 Advances in Food and Nutrition Research Steven L. Taylor (ed.), Elsevier.
  • Siebert, K. J. (2006). Control Systems: Chemical Analysis in Brewing. p. 372-390 New Technologies to Improve Brewing Performance and Beer Quality C.W. Bamforth (ed.), Woodhead Publishing Ltd., Cambridge, UK.