|Spontankoppi, Coffee IPA, and Spontankriek.|
Frequent readers of the BCBB will know that I've got quite a thing going on for the beers of Danish gypsy brewers Mikkeller. On a recent trip to The Jug Shop I picked up some more of their beers. Two of them interested me because they went with a "wild" yeast fermentation, and two because they had coffee in them. I love coffee.
Now, most brewers are very cautious about the yeast they let into their beer, and with good reason. While the behavior and flavor profile of good ol' S. cerevisiae is predictable, there are around 1,500 known species of yeast. They're all over the map, and a lot of them will spoil beer (and food), and a few are down right dangerous.
Probably the tamest "wild" yeasts are the Brettanomyces (affectionately known as "Brett" among brewers), which are what make sour beers sour. But even Brett is a tricky beast. It produces flavors that can be described as "metallic," "leather," or "barnyard," which can easily overpower a beer. It also has a much slower metabolism than S. cerevisiae, so beers with Brett typically require longer aging. And, they can metabolize sugars that S. cerevisiae can't, meaning that Brett fermentations will go on long after the S. cerevisiae are done - which can mean they take much longer to be finished, or, if you bottle them too early, they can build up too much CO2 in the bottle. And, finally, they can be damned difficult to kill off, so if they get into your brewery, and you don't want them there, you may be out of luck. You'll either have to switch to brewing sours, or get a new set of equipment. Consequently, very few homebrewers ever make sour beers, and they have to be very cautious when they do.
It's possible to buy commercial strains of Brett and pitch them into your beer. The more traditional method is to go with a "spontaneous" fermentation, where you let your beer into contact with the natural yeast in the environment. (This is also how traditional sourdough starter is made.) One way to do this is to ferment your beer in used wine barrels. Wine is usually fermented naturally using the yeast that's already accumulated in the fruit themselves, and a certain amount of that will be Brett, which builds up over time in the barrels. Another traditional method, used to make Belgian lambics, is to open the rafters of the brewery to the winds, and allow airborn yeast to accumulate in the spiderwebs and cobwebs, which then fall into the fermentation tanks...
Coffee, meanwhile, is an interesting and challenging ingredient for brewers to work with. A number of styles of beer, particularly porters and stouts, would seem to lend themselves to the addition of coffee, since they share similar flavors. But coffee (and similarly, cocoa) contain oils, most notably caffeol (which is primarily responsible for coffee's aroma and flavor), the oxidation of which can cause them to go rancid. (I've haven't myself used coffee in beer, but it's something I'd like to try, if I can find a good method.)
Kriek is lambic with cherries added. The beer itself is usually a Belgian lambic, which is a fairly light-colored and flavored beer. In some cases, kriek is made by adding a cherry syrup to a lambic, which can be a bit cloying. The more traditional method is to add cherries, with their attendant load of wild yeast, to the fermenter.
Spontankriek is clearly the latter sort. It's puckery tart, the sour cherry flavor mixing seemlessly with the sour beer. If you like sour cherries or sour beer, you're going to love this. 7.7% ABV.
Having thoroughly enjoyed the Spontankriek I was really looking forward to the Spontankoppi. But I have to say, I think the first word out of my mouth was... "ouch." I don't know how they got the coffee into the beer, but it was extremely strong and bitter, like the strongest cup of black coffee you've ever had, and then some. (Admittedly, I like my coffee strong, like barely fit for human consumption, but with lots of milk and sugar.) The sour beer was reduced to almost a footnote. If you get off on really strong black coffee, you might enjoy this, but I didn't. 5.3% ABV.
After the Spontankoppi, I had some trepidation about the Coffee IPA. Particularly since it came in a wine sized 750 ml bottle, so good or bad, I was going to be drinking a lot of it (Dr. P doesn't care for hoppy beers).
Fortunately, it was everything that I'd hoped the Spontankoppi would be, and more. The IPA base wasn't agressively hoppy, focusing on the citrusy and fruity notes, with a good malt backbone. The hand of the coffee was much lighter, not bitter, with toffee notes that matched the malt, and fruity notes that matched the hops, with just a hint of coffee bitterness on the finish. This was definitely the hop-head's coffee beer. 6.9% ABV.