Here is the short report I promised to write of my visit to Rodenbach Brewery in the end of October (as a part of the YSS2014 conference). I took notes on my phone, so I have to apologize that a) I didn’t manage to capture all the details, b) there may be some inaccuracies in my text. Anyways, we arrived at the brewery in the evening after a 1.5 hour bus ride from Gent. Here, Site Manager / Brewmaster Rudi Ghequire welcomed us and took us on a tour around the brewery.
We began by visiting their new brewhouse (finished in 2001), which was supplied by Meura. It is a 250 hL brewhouse, which is capable of doing both decoction and infusion mashing. Below are some pictures of the boil kettle (I think) and the mash filter. We have a similar mash filter in our pilot brewery here at work, but it is of course much smaller (1 hL brewhouse). Rodenbach beers are quite lightly hopped, and the brewery uses hop extract in the boil. After the boil, the wort is cooled and aerated with sterile air. After this it is transferred onwards for primary fermentation.
Rodenbach carries out their primary fermentation in 1 of 10 of their stainless steel cylindroconical vessels (I didn’t manage to capture the size). Primary fermentation is carried out for one week at 20C, after which the beer is cooled to 8C. The wort is pitched with a blend of Saccharomyces yeast and lactic acid bacteria (I’m not sure if they pitch any Brettanomyces?). After fermentation, some of the beer is transferred to wooden vats for aging (more of that later), while the rest is used for blending. The ‘regular’ Rodenbach is 75% fresh beer and 25% aged beer, while the Rodenbach Grand Cru is 33% fresh beer and 66% aged beer. Rodenbach Vintage is 100% aged beer. Below you can see pictures of the fermentation vessel and their airlocks (slightly bigger than the homebrew versions!).
Next we moved on to the bottling hall. Rodenbach is today owned by Palm Breweries, which means distribution is probably better than it has been previously. Rodenbach also contract brews for other breweries (which ones, I do not know). While we were there, we got to see Tripel Karmeliet (Brouwerij Bosteels) getting put into corked 75 cl bottles. Really fascinating to see these traditional beers getting packaged with modern automated technology. They had quite an impressive wall of empty beer cases waiting to be filled in the hall.
After this we made a quick tour through the old brewhouse (which I think is some kind of museum now), after which we walked through the vat cellar. Rodenbach apparently produced geuze previously, by cooling their wort in a coolship, but they stopped doing this in the 1970s. I unfortunately don’t remember the reason, but maybe they though they had more control over their brewing process with their current fermentation methods. Anyways, after primary fermentation, a portion of the fresh beer is transferred to one of 294 wooden vats, made from French oak, where it is allowed to mature for 2 years. During this time, the beer develops stronger lactic and acetic acid notes. The vats stand vertically (which was pointed out as an important characteristic for the flavour), and are not filled completely. This is to allow some air in the headspace, which promotes the growth of acetic acid bacteria. The vat cellar is kept at 15C, which I guess keeps metabolic activity of the microbes at a lower rate. Rudi told us that the beer develops a thick pellicle in the vats, and that a thick layer of beer stone also builds up along the inside of the vat with time. This means that the flavor contribution from the wood decreases with vat age. I don’t remember the life-time of the vats, but I think it might have been around 50 years if I’m not completely mistaken. A batch of Rodenbach beer is blended from several different vats, since they can taste very different. New vats are made at the brewery in their wood-working shop. Before they are used for beer, they are ‘wetted’ for three months to proof the wood.
After the tour, Rodenbach were kind enough to serve us dinner and beer (thank you!). I’m normally not that big a fan of sour beer, but I thought both the regular Rodenbach and the Grand Cru were really refreshing and nice (not too acidic)! No surprise that the great Michael Jackson once said that Rodenbach Grand Cru is “The most refreshing beer in the world”. Thank you Rudi (standing in the background behind my glass in the picture below) for your hospitality!