Release and Evaporation of Volatiles during Boiling of Unhopped Wort

• Published in: Journal of agricultural and food chemistry Vol. 56; no. 13; pp. 5172 - 5180
• Main Authors: De Schutter, David P, Saison, Daan, Delvaux, Filip, Derdelinckx, Guy, Rock, Jean-Marie, Neven, Hedwig, Delvaux, Freddy R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 09.07.2008
• Subjects: alcoholic fermentation; Beer - analysis; beer aging; Biological and medical sciences; boiling; Chemical Changes Induced by Processing/Storage; Edible Grain - chemistry; evaporation; Food Handling - methods; Food industries; food processing; food processing quality; Fundamental and applied biological sciences. Psychology; furfural; Gas Chromatography-Mass Spectrometry; hops; Hot Temperature; Hydrogen-Ion Concentration; Maillard reaction; TBA; thermal load; Thiobarbiturates - analysis; thiobarbituric acid-reactive substances; Time Factors; volatile compounds; volatiles; Volatilization; wort (brewing); Wort boiling; Maillard reaction; TBA; Wort boiling; thermal load; volatiles; Volatile compound; Heat treatment; Evaporation; Boiling; Release
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf800610x

The release and evaporation of volatile compounds was studied during boiling of wort. The observed parameters were boiling time, boiling intensity, wort pH, and wort density. The effect of every parameter was discussed and approached chemically, with an eye on beer-aging processes. The results indicated that pH highly influenced the release of flavor compounds and that the formation of Strecker aldehydes was linear with boiling time. However, because of evaporation of volatiles, information about the applied thermal load on wort is lost when using a volatile heat load indicator. The thiobarbituric acid (TBA) method, which includes the nonvolatile precursors of volatile aging compounds, proved to be a more reliable method to determine all kinds of heat load on wort. Finally, it was discussed how the obtained insights could help to understand the mechanism of beer aging.