Beers labelled as hemp beer are already commercially available. However, these types of beer contain hemp as an addition to and not as a substitute of hops. As a consequence, they usually have a typical hemp flavour. “This is exactly what we didn’t want,” says Amandine André. “Instead, we wanted to develop a product that tastes exactly the same as traditional hops beer.” The Swiss brewery association is highly interested in the hemp experiments of the ZHAW. This project could help Swiss breweries be considerably less dependent on hops imports, as hops does not grow particularly well in Switzerland. About 90 percent of demand is therefore met by imports. According to the ZHAW researcher, hemp, on the other hand, thrives in Switzerland. “The plant hardly needs any fertiliser, pesticides or irrigation,” she explains. Moreover, hemp is heat-tolerant and, unlike hops, can easily endure changes caused by global warming.

After searching for suitable hemp varieties and the right recipe for almost three years, Amandine André has now made a major leap forward in her research. Two hemp varieties were singled out as having increased levels of bitter compounds and aromatic descriptors common to those of hops during plant experiments conducted at the ZHAW campus in Wädenswil. The ZHAW researcher performed several experiments to find the right blend for a brand-new hemp beer. She also analysed the chemical structure of the hemp variants and aimed to identify the molecules responsible for their bitter taste. In order to identify and analyse previously unknown hemp bitter agents, Amandine André utilised analytical methods such as mass spectrometry and high-performance liquid chromatography. During these experiments, she discovered that the bitter agents of hemp differ from those of hops in chemical terms.

The analysis was followed by different brewing trials and sensory tests involving the two chosen hemp varieties. The researcher concluded that three to four times more hemp than hops is needed to brew a high-quality beer with a similar bitterness level. Moreover, Amandine André realised that it is best to add the hops only shortly before the boiling process finishes and not 90 minutes earlier as is common while using hops, as otherwise the bitterness level decreases. Up to three quarters of the hops can be replaced with hemp without compromising the bitter taste. Two different pilsner-style beer recipes were developed at the ZHAW based on these findings. The first type was a pure hemp beer without hops. For the second type, however, the amount of hops in the pilsner recipe was reduced to one quarter.

Blind testing was carried out after weeks of storing the beer. The two hemp beers that were brewed by the ZHAW researcher were compared with a standard commercially available hemp beer exhibiting a pronounced hemp flavour. During testing, hemp and hops flavours, citrus and fruit flavours, sweetness, bitterness and general preference were evaluated. The pure hemp beer brewed by the ZHAW researcher turned out to have a more subtle hemp flavour than the commercially available beer and was also sweeter and less bitter overall. However, as the aim of the experiment was to develop a beer with a nearly identical taste, the researcher decided to compare the hemp beer that had been supplemented with hops with a commercially available lager that exhibited an identical level of bitterness. The ensuing results are promising, with none of the seven test persons being able to discern any differences between the ZHAW beer and the standard lager. Both beers tasted equally pleasant, bitter and didn’t have a hemp flavour. The ZHAW researcher aims to test the beer once more after storing it for several months. Afterwards, Amandine André plans to refine the brewing recipe and wants to find a brewery to partner with so that the hemp beer can be further developed to be market-ready in the future.