So we were recently at the Faculty of Bioscience Engineering.
What's your connection to that place?
Well, that’s simple; it’s my faculty!
where I was also studying yeast.
Before that I actually did my PhD in that building of Bioscience Engineering.
So I was in the brewing school, doing my PhD.
That's where I got hooked on yeast and beer, I guess.
So I found this in your office. Can you tell us something more about it?
That's my lunch you have there! Give it back!
This is the official University beer actually. So, KU Leuven has a beer.
You can actually buy this in the University shop downtown.
So this is where we keep all the yeasts. Our treasure.
There's a lot of them, as you can see. All these boxes.
And each box contains a hundred different ones.
So every little tube is a different yeast and so we have breweries from
all across the world that give us their yeast and we keep it for them.
So if the brewery burns down, we can resend their yeast
and they can still make their beers.
But why is it so important? If the brewery burns down,
why can't they generate different kinds of yeast?
Ah, because every yeast is different.
So every beer is made with a different yeast.
So one of the things that makes a beer distinct
and differ from each other is the different yeast they use.
This has been going on for more than five years now.
What we have here are six reactors in the back;
you can hardly see them with all the cables and bottles.
There are six reactors that have been going for five years.
There's different yeast in them and so these bottles here contain food for the yeast.
But we also pour alcohol in them. And so they're continuously getting more food,
slowly, but continuously. And also we pump the same volume out of the bottle.
So it's a continuous culture.
And so the yeasts are dividing and growing in there.
And we're always - slowly, every month or so - we're increasing the alcohol level
that we put in these bottles.
So these yeasts are exposed to more and more alcohol.
It's like we give them more and more beers to drink, in a way.
And what we hope and what they're doing is,
they're genetically adapting to higher alcohol levels. So their DNA is changing
and slowly but surely, through Darwin pretty much at work,
their DNA is changing to make them more resistant
to higher alcohol levels, because alcohol is toxic.
Not only for humans but also for yeast.
But how is it useful in chocolate and biofuels?
Well, biofuels is kind of obvious in a sense that
bioethanol, so alcohol, is increasingly important as an additive to fuels.
So that's made by yeast cells and we just try to create yeast cells that are making more alcohol.
Chocolate is a different story.
Chocolate is also fermented, so microbes play a role in chocolate.
Chocolate grows on cacao trees and these trees have pods
- a bit like coconuts, this size.
And inside these pods you have about 30 to 50 beans.
But they're surrounded by a gooey pulp.
So when these pods are harvested, the farmers cut them off with their machetes
and they cut open the pods and they spill the beans onto this big heap on the soil,
right there on the farms.
And then you have microbes falling in and they eat away the pulp
that surrounds the beans
and so in about a week or so the pulp disappears, liquefies and disappears.
It's a spontaneous process so you just have the microbes that are present there at the farms that do this.
But it's not always ideal. Sometimes the wrong microbes get into the beans
and you get chocolate that doesn't taste very well.
So one of the things we're doing is to try to make microbes that
are doing a better job at fermenting these beans.
What are your favorite beers personally?
Oh, my favorite beers? I like the Trappist beers.
I think they're really good so I'm very proud of them.
It's really heritage, right. You have these monks making beer
and we actually do a lot of work for them.
I'm also very proud of the the largest brewery we have right here in town.
AB IMBEV, right? The largest brewing concern in the world.
So that's something to be really proud of if you're working here in Leuven.
And that's a really fun company to have as a neighbour as well.
I like Duvel, which is again a Belgian classic.
But to be honest, you know, you have to taste all the different beers, right?
There's a good beer for every occasion.
So I don't think we have many bad beers.
It's about drinking what you like at a specific moment. At a specific time during the day.
Yes, perfect. There's a beer for every time of the day.