As promised, I will talk more about the research aspect of this project. From the very start of the European Joint Doctorate, each Early Stage Researcher (ESR) was given a specific task/topic.
My goal was to come up with (working) strategies to reduce the iron intake during brewing. You see, iron—and other transition metals, such as copper and manganese—are major catalysts for several undesirable reactions that occur during brewing and the storage of beer. To be more specific, they drive oxidation and are thus a big factor as to why beer turns stale over time.
Gotta Catch ‘Em All!
From the get-go, in order to tackle this problem, I decided to adopt a physicochemical approach: trying to capture the unwanted metal ions by chelating them and filtering out the resulting metal-complexes.
The first big questions to address were:
- which chelators would be eligible for this? and
- would they also work in a wort and beer (simulated) environment?
To answer the first question, I had to scan the literature for potentially promising chelators that would be able to capture Fe, Cu, and Mn. I limited myself to food-grade compounds and chose a total of nine chelators. To replicate a beer and wort environment, I made separate buffer solutions that would mimic their respective acidities (4.3 and 5.6).
Mixing & filtering
Next step was, simply put, mixing separate metal ions—the “bad” ones (Fe, Cu, Mn), but also the brewing essential ones (Ca, Mg, Zn)—with each of the nine chelators, and check whether complexes were being formed. The latter was done by UV-Vis spectrometry; but on top of that, I also filtered the mixtures (after 1 hour of reaction time) in order to see if complexes were being formed and whether it was possible to remove them through filtration. I did this by analyzing the filtrate for leftover metal and comparing it to blank values (no chelator added). If the complex is big enough to be filtered out, then the metal level should drop.
What I found out
This study showed that a few chelators definitely had potential in reducing transition metals (primarily iron) and that chelation is especially apparent at a higher pH (so, wort > beer).
I followed-up with a study to determine whether these compounds would display the same behavior in a more realistic brewing setting, and if yes, how their chelation capacity could be optimized through parameter adjustments (finding the optimal working pH, chelator concentration, temperature, addition time, etc.).
While this study brought forth some very interesting effects, filtering out complexes by lautering alone proved to be difficult. In the hope of replicating the metal reducing effects of the most successful chelator (tannic acid), I searched for alternative compounds with similar chemical makeups. As hoped for, some very promising natural substances came to light; and just in time for my secondment at the University of Leuven (Ghent Technology Campus, Belgium).
We more-or-less arrived at the current point in time. I’m conducting my third study at the KU Leuven brewery, where I’m checking if I can replicate the results seen in the lab trials (successfully taking out iron during mashing) on a big scale; and whether adding my novel compounds truly result in producing a more (flavour) stable beer, like my initial ESR topic envisioned.
Now, if you want to delve deeper into the actual science, or you want to know more about the technicalities, published papers are on the menu and for the (near) future. Stay tuned.
If you’re curious about how the EJD adventure has unfolded since my previous blog. make sure to keep an eye open for my next blog update where I’ll write more about the project and my personal experiences.
As always, thanks for reading and stay fresh!