Fig 1: Cantillon’s Lou Pepe 2007 Gueuze
Eureka, this is another post concerning wild yeast isolation from a commercial beer. Today’s beer is Cantillon’s Lou Pepe 2007 Gueuze. I got a bottle of this particular Gueuze a year ago and stored it for another year in my cellar. By the end of June 2012, I finally got the opportunity to open the bottle and taste it.
Before heading into the tasting notes, let me give you some background information about the beer. The label on the bottle says: “Our Lou Pepe beers are all exceptional products. We only use the finest lambic to make these beers. The Lou Pepe Gueuze is a blending of only 2 years old lambics. Beer with tasteevolution. Best before 12/2029” (Fig 2). It comes in 0.75 L bottles and 5 ABV. Bottled on the 12th of October in 2009.
Smell: Very funky and a lot of horse blanket, leather and barnyard
Taste: Very light sourness, pretty dry on the palate, grainy. Some lemon and wood notes as well. Rather nice sourness (no vinegar). Subtle notes of funkiness.
Appearance: Pours in a golden-yellow color, clear and a pretty nice white head. Not very long lasting head though. Very fizzy. Looks like a champagne
Mouthfeel: Light body, average carbonation, dry and astringent aftertaste. Some bitterness is there as well
Overall: Not bad and very easy drinkable. Not a very sour and complex Gueuze compared to others. However, a good example for the style. My rating: 80/100. I expected this beer to be more complex and less astringent.
Fig 2: Bottle description
I then streaked some of the bottle’s sediment on some Sabouraud agar plates and left the plates at room temperature for approximately three weeks until colonies were visible. I could observe two different kinds of colonies (Fig 3).
Fig 3: Cantillon’s Lou Pepe 2007 sediments on Sabouraud agar
The most colonies were similar to the whitish colonies marked as 2 in Fig 3. And there were some darker colonies (light beige) marked as 1 in Fig 3. Nearly two years after bottling the Gueuze there are still some living organisms in the bottle. The morphology of these colonies is very similar to other Brettanomyces I isolated before. I expect these colonies (marked 2) to be Brettanomyces. On the other hand, I have no clue what the microorganisms in colony 1 could be since the color is very different from Brettanomyces or Saccharomyces colonies. Maybe the micrographs give me further information? Next step was to do some microscopy observations of the two different colonies. Lets begin with the colonies marked 2 in Fig 3.
Fig 4: Micrograph of colony 2 (see Fig 3)
Fig 5: Micrograph of colony 2 (see Fig 3)
To me, the colonies shown in Fig 4 and 5 look like a kind of wild yeast. At least no Saccharomyces cerevisiae for sure. Or any other kind of bacteria due to the size of these cells. I expect these cells to be Brettanomyces due to the elongated shape of the cells and other characteristics. The cells could be Kloeckera apiculata, Pichia membranaefaciens or Hansenula… The list is not complete here. Further investigations are necessary. What about the other colonies?
Fig 6: Micrograph of colony 1 (see Fig 3)
Fig 7: Micrograph of colony 1 (see Fig 3)
First of all, the cells shown in Fig 6 and 7 look very different from the ones shown in Fig 4 and 5. These cells here are mostly circular and look very similar to Saccharomyces cerevisiae cells. Aggregation of Saccharomyces cerevisiae as it can be seen on the upper left corner in Fig 7 can be observed in wheat yeast samples as well. For me theses cells look like typical Saccharomyces cerevisiae cells although some cells seem to have a more elongated form as well. I will have to do further investigations to get more information about the cells in colony 1. Wouldn’t it be cool to have isolated some Saccharomyces cerevisiae yeast cells from an old Gueuze from Cantillon?
To summarize, I could isolate two different kinds of yeasts from a Cantillon Gueuze bottled in 2009. I have a strong feeling the cells from colony 2 belong to the specie of Brettanomyces. This is just a feeling. The strains go into my library as B05 (colony 2) and Y03 (colony 1). Further investigations are necessary to differentiate the two different strains. Cool stuff. The only verified conclusion here is: It is possible to isolate some yeasts from a Gueuze that is nearly two years in the bottle. Stay tuned for further yeast related posts!
Eureka Brewing 
Hmmm… Number 1 looks like some wild Saccharomyces, and 2 indeed looks like Brett. Try seeding on bromocresol green to find out.
Maybe it’s just me, but it could be that you have another colony type there? The ruffled ones towards the top-left?
I also streaked some of colony 2 on a newly developed sour-agar to see what happens. I can’t remember now how much acid I added. I have to check my lab journal. However, I just added some phosphoric acid to the sterilized agar. The agar should be cooled down as much as possible to prevent an autolysis of the agar due to the acid. I could observe only Brettanomyces can grow on this agar. All the Saccharomyces I tested showed no signs of growth. Colony number 2 formed some colonies as well. Unfortunately, I haven’t streaked some of colony 1 on the sour-agar because I observed these colonies rather late…
Bromocresol green. I did some testing with that stuff as well but I still have to look through the results.
I can’t tell if the ruffled colony is yet another organism since I do not have the plate anymore. To me it looks like a colony that had more time to grow than others and therefore grew to a bigger yet ruffled colony.
Thanks for commenting and I am really looking forward how your Brettanomyces batches turn out. Cheers Samuel