Schottle, B.1, Surridge, B.2, Carriere, K.2, McPherson, L.2, Guan, C.2, Dolberg, J.2 and Thomson, E.1, (1)Phillips Brewing & Malting Co., Victoria, BC, CANADA, (2)Camosun College, Victoria, BC, CANADA
Technical Session 5: Stability
Tuesday, June 06, 2017
8:30–10:15 a.m.
Camellia AB
It is believed that a stable foam layer on the surface of poured beer slows the release of volatile flavors to the atmosphere, enhancing sensory evaluation. Additionally, the presence of healthy beer foam is considered to be both aesthetically pleasing and serves as a visual indicator that a beer has been well crafted. Discussions with fellow brewers uncovered similar observations that the foam stability of their bottled products was superior to their canned products. As a result of the observation that bottled products were consistently demonstrating superior head retention compared to their canned counterparts, even when the same batch was packaged in both formats, we sought to determine the underlying cause of weakened head retention in cans and develop a method by which other breweries could solve similar issues. Head retention was observed during sensory evaluation of heat-forced samples. Four bottles or cans from each packaging run were stored at 30°C, and head retention was observed in each of the four subsequent weeks. To identify compounds present on foam-negative and foam-neutral can lids, lids sampled from four sleeves by two manufacturers were rinsed with methanol followed by toluene. The resulting solution was analyzed using gas chromatography/mass spectrometry (GC/MS). Varying amounts of clear, colorless lubricant were discovered on the beer-contacting surfaces of the can lids observed to negatively impact beer foam. Lubricant was not detected on control can lids obtained from a second manufacturer, and the absence of lubricant correlated with improved beer foam. Butyl stearate and butyl palmitate were identified in the solvent solutions, collected after rinsing the suspect lids, and absent in control solutions of both methanol and toluene. While butyl stearate was found at up to 0.15 mg per can lid, butyl palmitate was found at levels up to 0.12 mg per can lid. These results outline a valuable method for identifying foam-negative lubricants added during can lid manufacturing that can inform brewers’ selection of packaging materials suppliers.
Benjamin Schottle studied biochemical engineering at the University of Western Ontario and has worked in the craft brewing industry since 1994. He currently works in the quality and research lab at Phillips Brewing & Malting Co.
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