Sensory and chemical differences between naturally and artificially carbonated beer

Sensory Session
Eric J Allain, Appalachian State University, Boone, NC, USA
Co-author(s): Ben Hogue, Seth Cohen, Brett Taubman, and Shea Tuberty, Appalachian State University, Boone, NC, USA

ABSTRACT: The importance of an appropriate level of carbonation to the sensory perception of beer is well known. Carbonation can be produced in beer naturally where dissolved carbon dioxide is produced by yeast or artificially in which external carbon dioxide gas is applied to the beer at a pressure sufficient to achieve the desired level of dissolved carbon dioxide. While both methods can be used to achieve a beer with identical dissolved carbon dioxide concentration, some claim that natural carbonation produces a beer that is perceptibly different than an artificially carbonated beer. We investigated this claim by brewing a number of batches of beer in which, after fermentation, half of the beer was artificially carbonated while the other half was naturally carbonated to the same level of dissolved carbon dioxide. Sensory evaluation and difference testing was performed using a triangle test to determine the ability of tasters to discriminate between artificially carbonated and naturally carbonated beer samples. A possible cause for any sensory difference between naturally carbonated and artificially carbonated beer could arise during the fermentation process that occurs during natural carbonation. This possibility was investigated by analyzing the beers using gas chromatography/mass spectrometry to identify any differences between naturally and artificially carbonated beers.

Eric Allain graduated from Illinois Benedictine College with a B.S. degree in biochemistry in 1990. Eric attended graduate school at the University of Illinois in Champaign-Urbana, where he received a Ph.D. degree in biochemistry in 1997. His thesis work involved development of an enzymatic synthesis scheme for compounds important to the pharmaceutical industry. From 1997 through 1999, Eric worked for Nalco Chemical Company, where he studied and developed enzyme applications for water treatment. In 1999 he joined Novozymes, where he worked to develop new enzymes for the fuel alcohol industry. Significant accomplishments include the development of lab-scale methods to study enzyme behavior in fuel alcohol fermentations, development of engineered enzymes that are up to 10 times more efficient in the breakdown of starch, and development of a mathematical model describing how systems of enzymes work together to catalyze the conversion of starch to glucose. In 2005 Eric joined the faculty of Appalachian State University as a professor of biochemistry. Here, he is part of a growing team focusing on brewing and fermentation science research. Eric also serves as a board member for The Ivory Tower Brewery, a full-scale education- and research-based brewery at Appalachian State University in Boone, NC.