Fatty Acids and Esters Produced During the Spontaneous Fermentation of Lambic and Gueuze

Abstract

Latnbic and gueuze are Belgian beers obtained by spontaneous fermentation of wort. During previous studies it was found that they result from the successive development of enterobacteria, Kloeckera and Saccharomyces yeasts, bacteria of the genus Pediococcus, and Brettanomyces yeasts. The beers are characterized by high concentrations of acetic and lactic acid, ethyl acetate and ethyl lactate. This study of the content of the higher fatty acids during a 20 month fermentation period confirms the succession of the different micro-organisms. Pure cultures of isolated yeasts and bacteria produced fatty acids which were also found in the fermenting wort at periods when these organisms were active. Lambic and Gueuze are especially rich in caprylic (C8) and capric (C, 0) acids. These are probably produced by Saccharomyces and Brettanomyces. Important amounts of ethyl caprylate and ethyl caprate were also found. As ethyl caprate is almost absent in other beers, it might be considered as another typical aroma component of lambic and gueuze.

Acid and Volatiles of Commercially-Available Lambic Beers

“…Seventeen compounds have been reported by both Van Oevelen et al [12] and Spaepen et al [18]. The compounds previously reported by Van Oevelen et al [12] were acetic acid, lactic acid, butyric acid, propionic acid, isobutyric acid, propanol, butanol, isobutanol, isoamyl alcohol, amyl alcohol, phenethylalcohol, ethyl acetate, and ethyl lactate.…”

“…The compounds previously reported by Van Oevelen et al [12] were acetic acid, lactic acid, butyric acid, propionic acid, isobutyric acid, propanol, butanol, isobutanol, isoamyl alcohol, amyl alcohol, phenethylalcohol, ethyl acetate, and ethyl lactate. Spaepen and his colleagues [18] reported finding caproic (hexanoic) acid, caprylic (octanoic) acid, capric (decanoic) acid, isoamyl acetate, ethyl caproate (hexanoate), ethyl caprylate (octanoate), ethyl caprate (decanoate), and phenethyl acetate. Rossi et al [17] used SPME to characterize the volatiles in different types of beer (lambic was not analysed) and reported that volatile fingerprints could be characterized based on the type of fermentation (top versus bottom) and style.…”

The Microbiology of Malting and Brewing

“…dominate the main, alcoholic fermentation, which lasts 3 to 4 months. Brettanomyces bruxellensis dominates the remainder of the fermentation and maturation (216), producing a range of characteristic aroma compounds in lambic, including caprylic and capric fatty acids and their ethyl esters (256,257). Brettanomyces also hydrolyzes EPS produced by Pediococcus during the main fermentation, reducing the viscosity of lambic (216).…”

The Impact of Simple Phenolic Compounds on Beer Aroma and Flavor

“…Interestingly, they also contribute key organoleptic qualities to specialty beer styles including lambic, gueuze, Flanders red and brown ales, Berlinerweiss, and others [36,37,[39][40][41]50,[60][61][62][63]. They are increasingly utilized in other new "wild" ale styles in the craft brewing industry.…”

“…This can range from inappropriate levels of otherwise pleasant aromas and flavors (spice, clove), to strong and offensive medicinal, plastic strip, goaty, burnt, or creosote character, among others [62][63][64]. The former situation may be due to inappropriate yeast strain choice (POF+ versus POF−), or fermentation at a temperature above the recommended range [91].…”