Some see brewing as an art, others as a science – Luc Van Loon combines both these virtues at his brewery. With the nose of a sommelier and the precision of a chemist, the former PSI researcher creates world-class beers.
The entrance to the brewery is inconspicuous, tucked away in a quiet residential street in Neuenhof – a tranquil Aargau village where stately half-timbered houses and babbling fountains make you forget the hum of the nearby motorway. Here, hidden in an old wine cellar, is the Chen Van Loon brewery. And this is also where the Sauvignon Ale is produced – the beer that, in 2024, was voted the third best beer in the world by the jury at the Finest Beer Selection, an internationally renowned competition.
Small but outstanding, you could say. “We’re a microbrewery,” explains Luc Van Loon, master brewer and former PSI chemist. Ten different beers are produced here – with a maximum capacity of 32,000 litres per year. “That’s how much Feldschlösschen produces in one hour,” he adds with a wink, referring to Switzerland’s largest and best-known brewery. “We’re definitely in a different league – our focus is on artisanal diversity and creative brewing styles. And that’s exactly what convinced the jury.
But how does a chemist end up brewing beer? Admittedly, the process itself can be expressed precisely in formulas – it’s pure chemistry. But Luc Van Loon came to beer not because of science, but through wine.
From chemist to winemaker to brewer
In 2005, Luc Van Loon leased a 0.3-acre vineyard and started producing wine in his spare time in the cellar of the winery Weingut zum Sternen in Würenlingen. At that time, the native Belgian had been working at PSI, just around the corner from his vineyard, for almost 20 years. Originally, he had applied for a position at the Swiss National Cooperative for the Disposal of Radioactive Waste (Nagra). But there were no vacancies at the time, so his documents were promptly forwarded to PSI. He sums up what followed: a call from PSI, a one-day on-site interview, and a friendly “You can start right away.”
And so, on 2 November 1988, the Van Loons and their two sons emigrated from Merksplas in Belgium to Kleindöttingen in Switzerland. Luc Van Loon had previously earned his doctorate in radioecology from the Faculty of Agriculture at the University of Leuven. His dissertation examined the behaviour of the longlived radionuclide technetium-99 – a legacy of the nuclear weapons tests of the 1960s – in agricultural products. Thus, his studies had already given him a keen understanding of soils, agriculture and how people shape them.
While Van Loon tended the vines in his spare time, harvesting grapes in autumn, pressing them and fermenting their juice, the substances he studied as a geochemist and head of the Diffusion Processes Research Group at PSI were very different. “We wanted to understand how radioactive substances behave in different materials – for example, how radionuclides migrate through Opalinus Clay and what interactions take place there,” Van Loon explains.
Opalinus Clay is a fine-grained claystone that formed around 173 million years ago from mud deposits on the seabed. Today, it lies several hundred metres underground and is of particular interest for storing radioactive waste in deep geological repositories, where it can serve as a natural barrier. “Our studies have contributed to a better understanding of the barrier properties of this rock,” says Van Loon.
- Mix malt with water and heat to 65°C – this produces sugar.
- Filter the resulting “wort” and heat to approximately 98°C (sterilise).
- Add hops – for flavour and bitterness.
- Place in a fermentation tank with yeast for about ten days – this produces alcohol and carbon dioxide.
- Chill the young beer to 10°C and bottle it.
- For additional natural carbonation: add some yeast and sugar and wait for bottle-fermentation to finish.
The experiments were conducted in the Hot Lab at PSI, a unique facility for the analytical investigation of highly radioactive substances. Access is strictly controlled through security gates, and the lab is surrounded by thick concrete walls. Lab coats are mandatory, and fresh air is scarce. “The physical labour in the vineyard was a welcome relief,” says Van Loon with a smile.
This work sometimes left him sweaty – and thirsty. “You have to drink a lot of beer to make a good wine,” joked Australian Christopher Chen about the hard work in the vineyard. At the time, Chen was working as an oenologist at Weingut zum Sternen and discovered a fellow beer enthusiast in the hobby winemaker Van Loon – who, as a Belgian, also hails from a true beer-loving nation. And so, in 2013, the two friends began brewing their first beer, purely on an experimental basis, using an old cauldron in the wine cellar.
We are a true family business – and that’s great.
Because they had no bottles prepared for bottling, they had to make do with some old champagne bottles from the cellar – and thus was born, quite by chance, the distinctive shape of the bottles that remains their beer brand’s signature today. Soon, they invested in a 200-litre system – but production increasingly clashed with the wine business. So, in 2015, they moved to Neuenhof – once again setting up in an old wine cellar.
The science of brewing
Although beer is made from four simple ingredients – water, malt, yeast and hops – the variety of flavours they can produce is almost limitless. “There are more than 50 types of malt and around 200 types of hops – not to mention the countless strains of yeast,” says Van Loon. External parameters such as temperature, fermentation time and storage also shape the beer’s character. “For me, that makes beer much more exciting than wine.”
Luc Van Loon fills a glass with golden, amberhued liquid from the tap of one of the large, silvery fermentation vats and carries it to his standing lab bench. Armed with a pipette and an array of measuring instruments, he begins his analysis. All that’s missing now are the lab coat and the gloves – and you could imagine yourself back in a PSI laboratory rather than a brewery.
The drop from the pipette lands in the refractometer. This instrument looks a bit like a telescope, but instead of looking into the distance, it is used to peer inside the liquid. Depending on the density of the beer, the incoming light is refracted at a different angle – this allows you to determine the sugar content. That in turn reveals how far fermentation has progressed in terms of how much sugar has already been converted into alcohol. An infrared device for measuring the effective alcohol content and a pH electrode are also available. “All that’s missing is a device for determining bitterness and colour,” says Van Loon. “Then my lab would be complete.”
When Luc Van Loon talks about his analytical methods, you realise you’re not just encountering a passionate brewer at work here but also an experienced scientist – one who is also well-versed in quality control. At PSI, Van Loon was responsible for quality management in the Laboratory for Waste Management at the PSI Center for Nuclear Engineering and Sciences. “It’s no different in a brewery,” says the brewer. “Here, too, we maintain strict records of our procedures and check the quality of our products – after all, the beer should always taste the same – with consistent colour, alcohol content and character.”
From a lark to a family business
Luc Van Loon has been brewing beer for more than a decade – and since his retirement in 2024, he no longer just brews on weekends. His former brewing partner, Christopher Chen, has since left the business and returned to his native Australia. Van Loon’s son, Jan, has joined the company – full-time. “I’m very proud that he’s taken the step into self-employment,” says Van Loon. The rest of the family is also on board: Jan’s partner takes care of graphics and marketing, and Luc Van Loon’s wife Anita handles the accounts. “We’re a true family business – and that’s great.”
At the moment, the Van Loons are working with a bachelor’s student from the Zurich University of Applied Sciences (ZHAW), exploring the potential of wine yeasts to release specific aromatic compounds in beer. “Our Sauvignon Ale, last year’s winning beer, contains a dash of grape juice from our own vineyard to enhance its fruity flavour,” Van Loon explains. “Our Vigneron – Cuvée du Patron, another award-winning beer, also tastes grapey but contains no fruit at all. The flavour comes entirely from the yeast. Its microbiological diversity holds enormous potential for new beer styles.”
Even in retirement, Luc Van Loon’s passion for experimentation and scientific work is undiminished. And his beer creations remain successful: in this year’s Finest Beer Selection, two Chen Van Loon beers achieved an impressive 95 out of 100 points – further proof that art and science can harmonise perfectly in the glass.
