Thursday, October 17, 2013

100% Brett Dark Strong Ale with Mulberry Molasses (O2/Acetic Acid Experiment) - Tasting Notes

100% Brett Dark Strong Ale

Brewery: Bear Flavored
Style: 100% Brett / Dark Strong Ale
Brewed: 4.21.2013
Bottled On: 8.1.2013
ABV: 10%

The more I learn about Brettanomyces, the more avenues for exploration seem to open up. There's so much still that we don't understand — or perhaps I should say, so much that is not common knowledge. I have long wandered what sort of effect barrel aging may have on Brett beers, outside of the flavors the wood itself may impart. Many Brett strains are able to produce acetic acid when given access to additional oxygen, and barrels create just these sort of conditions. So my question, then, was: could I emulate a barrel aging environment by introducing a limited source of O2? And could I determine whether there was any significant acidity or flavor difference resulting from this O2-exposure, by splitting the batch in two and limiting the amount of oxygen to traditional homebrew / carboy levels?

To read more about my methods and thoughts behind this experiment, read my original post, with the recipe, right here. To sum it up quickly, this batch was split between two carboys. One carboy received an airlock, as normal. The other was plugged up with a foam stopper and loosely covered with tinfoil for about a month — not the entire three months it aged, as I worried that would be too much. Now, dear readers, it's time to taste the difference in these two versions of 'Mountebank'.

Appearance: Designed to emulate a Belgian Dark Strong ale in many ways, I think my grain bill was pretty spot-on. Mountebank pours with a thick, creamy head. Great clarity as far as I can tell, though the beer is dark enough that it would be difficult to see if there was maybe a bit of chill haze. Looks like a very dark mahogany when glancing at a full pour straight on, but the edges fade to a very dark ruby reddish. It almost looks like a glass of port wine.

The O2-exposure version threatens to gush out of the bottle if you aren't ready with a quick pour, and the head is appropriately huge and foamy. As it settles, the head forms a nice creamy cap that lingers for a very long time. 

Aroma: Starting with the Control Portion, which received an airlock and therefore limited O2 exposure. Very interesting aroma — a mix of dark fruits, cherry, plum and mulberry especially, that each express themselves very dryly. Slightly tannic, like dried fruit skins. The malt makes itself known with a general sweet aroma, that nicely contrasts the tart fruit smell of the Brett. Like many Belgian dark strong ales, with really rich fruity malt yeast combinations, this has the suggestion of candy fruit. The oak presence seems fairly mellow at first, but probably blends right in with the dry tannic fruit skin aroma I'm getting. 

The aroma on the O2-exposure version doesn't strike me as terribly different from the Control portion, though the subtle differences add up to some important things. It does seem a bit mustier, a bit funkier, with an almost leathery earthiness. The same fruit flavors are present, but they are less rich, more funked up. Happily, this smells not unlike a young Flanders Oud Bruin. 

Flavor: Starting again with the Control Batch, it strikes me that I rarely try beers of this sort which are this dry, and yet also very malty and yeast-fruity. There's no sourness or bitterness to really balance things out, but as was my intention, the beer finished dry enough that all these rich dark-fruit flavors aren't cloying. If the malts were too heavy, I imagine this might be a real tough beer for me to have more than a few sips of. The oak helps add some depth and mouthfeel-balance, though it's more subtle than I expected. As with the aroma, there's a bit of that fruit candy — almost cherry cough syrup-esque? — but it's not as slick as it might be in another beer. The unique balance creates something that, while definitely a sipper, is still approachable. However, the dryness does allow some tannins to touch down and slightly linger — an astringent bitterness that tastes like it might be coming from the mulberry molasses; maybe a bit from the oak. 

ABV-wise, neither shows the high level of booze these are carrying. I have noticed this in all my 100% Brett beers, and earlier this year, crushed enough bottles of my Brett Trois imperial IPA to wonder if Brett perhaps doesn't produce alcohol at the same ratio as Saccharomyces. Whatever it is, this has the flavors of a big boozy beer, but it sure doesn't kick like one. I've had 6% ABV beers that taste boozier than this.

The O2 version starts off with the same unique balance as the Control Version, the same vaguely-Belgian fruit notes and esters, and for a few sips, I was worried the two splits might be boringly identical. But while the variation certainly isn't drastic, I quickly saw that it was there, and significant in spite of its subtlety. The Control Portion finishes with that tannic dryness I mentioned, but the O2 portion has a nice acidic snap to close it out instead. It's the tail-end of that Flanders-esque complexity found in the nose, though this tastes much further from an Oud Bruin than it smells. The fruitiness — whether because of that slight acidity, or some other enigmatic shift in balance — seems much more vibrant and bright, rather than dry and aged. Overall, the O2-exposed portion just seems more alive, more composed, more colorful. There is no shocking brace of acidity, which left me a bit disappointed at first, but there is a boost in tartness and colorful funk that is noticeable, and goes a long way in rounding out the beer. 

Mouthfeel: The palate of the Control Portion is surprisingly unmemorable. I don't mean that in a bad way — I forgot I was going to have to take notes on that aspect until I was done with my first glass, and by then, I couldn't really remember the mouthfeel in specifics. Medium bodied, but seeming lighter due to the overall dryness and the well-masked ABV. The O2 portion, due to the higher level of carbonation, obviously comes across as creamier and fuller, lighter on the tongue. While I'd prefer the bottles didn't gush, of course, this is definitely a benefit to the beer, and probably another reason I prefer the O2 version over the airlock version.

Overall Impressions: With most batches I can picture pretty clearly what I want the beer to taste like in the end, and then afterwards correct myself based on how close I got. Here, I truly had no idea what to expect (despite my hopes and goals), so reviewing these two versions of Mountebank is a lot like reviewing a completely unknown commercial beer of vague description and character. Drinking my first bottle of the Control Portion of this batch, I thought: "Okay, this is interesting. I would try brewing this again, if people liked it enough. Could be cool to age on actual fruit." But drinking the O2-exposed version, suddenly it dawns on me that, wow, I really like this. It's a weird brew, but yet incredibly similar to traditional Belgians in many ways; a contrast in expectations that I especially like toying with.

Another semi-surprise: the O2-exposed version ends up being the clear winner, though not for the reasons expected. It's equally dry, but also juicier, livelier. I really felt this could have gone either way, and while neither version tastes particularly acetic, the difference in aroma and complexity — a subtle shift in the framework of the beer — is enough to give it a firm edge.

Click here for the recipe and initial notes for this batch.


  1. I noticed that added a sizeable amount of Belma hops late in the boil, but it doesn't seem to show up in your tasting notes. Do you think that the hops had much impact on the final product?

    1. I haven't really been able to pick them out in my tastings so far, no. I had been wanting to use up those hops and I figured they would compliment the flavor here if they did show up, but I kind figured it was a long shot. Brett tends to chew up hop character during fermentation, and with the extended aging time.... I probably will just skip the late additions next time and get whatever IBUs I need from a small 60 min addition.


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