Science is not always dry as dust

DOSSIERS
Brewing beer toan 18th-century recipe  Objectives
The brewing process
Science happening in Bokrijk
Science is not always dry as dust
The “Paenhuys van Diepenbeek”
Scientific analysis of a historic brewing process (dating from 1750)
Sources

No-one really knows how things were at these small home breweries circa 1750. However, what is all too clear is that the brewers back then had a really hard time. No closed systems, no gas, only wood to fuel the fires, no automatic stirrers, no pumps for the boiling water, … brewing in those days was a genuine craft, passed down by tradition, in all the sweat of the brow you might expect. From a strictly biochemical viewpoint, brewing is quite easy in this brewery. But this is not a case of ‘brewing by numbers’, to modern biochemical know-how, it’s a case of rolling up your sleeves, and getting stuck in! The only thing that really counts is re-enacting, in a historically correct manner, the brewing of 1750 using the available historic infrastructure. This may seem an odd choice for a university offering a course in biochemistry but without a course in brewing technology and applied science. But enthusiasm is great, and the intention is clear: the University of Antwerp regards this project as a challenge that should provide new insights in this historic brewing process and, by its very atypical character, fit in perfectly with the mission of the university (Education, Research and Provision of Services). It is also an excellent way to show the university from another angle: science is not always in deadly earnest; it can sometimes be an adventure in an exact historic and scientific context.

Ticking things off, one by one, it begins to dawn on us why so many should have declined the offer,… Given the size of the different tanks, and after a spot of mental arithmetic, we arrive at a minimum volume of some 1 500 litres if we don’t want to end up with a forlorn-looking puddle of liquid in the bottom of the tank. And these 1 500 litres have to be drawn off, stirred, filtered and pumped by hand. As a biochemist, as a home-brewer, I know only too well what it means to work a full 30 litres of sticky, boiling sugar-water at 110°C (!), never mind 1 500 litres. Nor is the prospect any more inviting once you discover that, at the start of the brewing process, you have to mix up 700 litres of water and 300 kg in the mash tun. An hour later you get a thick, viscous pulp. If 30 litres is difficult to stir using just a big spoon, you can imagine the effort required for 1 000 litres if you have to use mash-staffs weighing 10 kilos each!

Workers, that’s what we needed: people who are interested, enthusiastic and, perhaps most of all, poor, unsuspecting, …and we found them. Friends, colleagues and acquaintances from the university, all pricked up their ears. So, eventually, we put together up a team of twelve men (and a woman). We certainly needed them! First, a stoking gang had to get up at the ungodly hour of 6 in the morning to fetch and boil up several hundred litres of water. Mashing began at 9 o’clock: bearing in mind that one mash-staff is worked by at least two persons, that the boiling copper has to be stoked at the same time, and that, meanwhile, people have to scoop and pump hot and cold water, 12 pair of hands is hardly a luxury. Stuikmanden, plate-filter boxes, then had to be stoked for filtering, scooping, ladling, running off, …And me? Well, I think I’ll go delegate a bit, … Later that day, a 6-hour simmer draws to a close with the manual pump-over of the seething wort into the cooling vessel. Only then (midnightish?) can our team crawl beneath the covers. A few hours’ sleep, then the brewery calls us back. Then we finally knock the spigot off the cooling tank and, after filtering, the old draff can be seeded back in the fermentation tank.

Now for the tank fermentation. The young (‘green’) beer is covered by a woolly sheet of top yeast that sinks to the bottom a few days later. That’s when the brewer knows that the time has come to run the beer off into barrels, to set the barrels on the stillage and, at long last, to sit back let the beer grow old gracefully. It’s mainly the added yeast that converts the sugars into alcohol and into carbon dioxide. However, since the curator was keen to brew the beer as authentically as possible (i.e., non-pasteurized), the local wild yeasts and bacteria, such as the lactic acid and acetic acid bacteria, were also invited to the party. In a word, the tap-end beer will host a motley crew of micro-organisms, each gracing the beer with its own peculiar taste and scent. Will the result keep its charms a few months hence? Authentic yes, but well, sort of … sour, bitter. ‘Dry’ beer, the lambic way, … a high note for ‘them as likes it’, and a bummer for the rest, … BOTTOMS UP!

 

Leave a Reply

Your email address will not be published. Required fields are marked *