What Gives Hoppy Beers Their Fruity Aroma? - Chromatography Explores

Craft and hoppy beers are growing in popularity. Drinkers are seeking out new tastes and flavours are smaller brewers are constantly introducing new flavours to our palate. Drinkers enjoy the variety of new and fruity aromas and tastes that these brews are bringing to the table. But until recently, the adage that brewing is as much art as science has never been truer because brewers have not had a suitable method to track all the different hoppy components responsible for the taste and aroma of your favourite pale ale.

Chromatography detects the thiols

But help is at hand thanks to researchers from the Research Institute for Beer and Beverage Analysis in Berlin. In a paper - Analysis of Hop-Derived Thiols in Beer Using On-Fiber Derivatization in Combination with HS-SPME and GC-MS/MS – published in the Journal of Agricultural and Food Chemistry the research team present a new chromatographic method that can assess the compounds behind the hoppiness in beer.

It seems that the compounds that are responsible for most of the aroma of hoppy beer are thiols. There have been methods to analyse thiols in beer used before; but these have been shown to be inaccurate and long-winded. Multi- step methods and methods using hazardous chemicals are all that analysts had to use. The new method needed to be sensitive as the levels of thiols in beer are very low. Luckily, the team have developed a method that starts with automated headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-tandem mass spectrometry (GC-MS/MS). Developments in chromatography are discussed in the article, Hybrid Structures for Complex Analytical Instruments.

Thiols in your glass

Thiols contribute to the aroma and taste of wine, and previous researchers have used polymers in the air above the wine to convert the wine’s thiols from aerosol form to more easily measurable compounds. Unfortunately, this method is not sensitive to analyse trace levels of thiols in beer. So, the researchers modified a sample preparation method from the wine method and applied a tandem mass spectrometry approach with a greater sensitivity.

The team used the method on 13 commercially available beers with different hop varieties that were expected to have high thiols values. The results were comparable with values obtained from previous studies. There was a finding that when beers were flavoured with fruits, the fruits themselves added to the scent. The method has demonstrated its ability to analyse the thiols in beers in a safer, quicker, and simpler method than previous methods.