Among other factors, one of the things that makes so-called hoppy beers so popular is their fruity aroma. A new process could allow brewers to better quantify the thiol compounds that produce that aroma, in the development of fruitier-smelling beers.
Although hoppy beers such as pale ales contain relatively small amounts of thiols, the compounds still have a pronounced effect on the aroma. Because the thiol levels are so low, though, detecting and measuring them can be quite difficult. Existing testing processes are complex, and even then aren't always very accurate. Additionally, some procedures require brewers to add toxic mercury-based reagents to beer samples.
Thiols are also present in wines, in larger quantities. Vintners measure their levels via specially-coated polymers that are placed in the air above wine samples, where they convert aerosolized thiols into compounds that can be more easily quantified. Unfortunately this procedure doesn't work on beer, as its thiol levels are much lower.
Scientists from Germany's Research Institute for Beer and Beverage Analysis have now modified the wine-analysis technique for use on beer, by converting the aerosolized thiols into compounds that have a much higher "analytical sensitivity" than was previously possible. This means the compounds are easier to detect and to measure, via tandem mass spectrometry.
In a test of the process, the scientists analyzed 13 different hoppy beers from various countries. In all cases, the detected thiol levels were found to be in line with those obtained using more complex, time-consuming methods.
A paper on the research was recently published in the Journal of Agricultural and Food Chemistry.
Source: American Chemical Society