Thursday, July 18, 2013

Kombucha / Brett Beer Farmhouse Ale - Recipe and Tasting Notes

Kombucha Brett Beer Farmhouse Ale


Brewery: Bear Flavored
Style: Farmhouse Ale / Kombucha
Brewed: 7.10.2012
ABV: 5.8%


Appearance: pale copper / red, great clarity, minimal head, very poor retention
Smell: Bretty funk, tart cherry pie, apple, oak, mild vanilla spice
Taste: crisp, fruity acidity, funky esters, tart 
cherry, apple, oak, dry, tannic finish
Mouthfeel: light
 body, medium-low carbonation, slightly slick

Kombucha is a wonderful thing. It's sour, it's flavorful, it's good for you, and you can drink it for breakfast. While it's nowhere near as complex as a good sour beer, but it's also much cheaper, easier to make, and easier to find in a store. (And if you would like to know how to make kombucha, I conveniently have a four-part guide to walk you through it). I am, of course, far from the first person to wonder if there was any merit in a sour beer / kombucha hybrid. Goose Island's Fleur is as close as I could point to a model for what I was aiming for with this batch, though a few other breweries have attempted blending kombucha with beer in different ways, with undeniably... interesting results. Meanwhile, many kombucha brewers are producing beer-like, tea-based drinks that essentially taste like gluten-free lambics, and even boast a hefty ABV. Kombucha-beers have not quite "caught on," but they're definitely out there if you know where to look.

There are a number of methods you could employ to create a beer / kombucha hybrid, depending what you're going for. You could simply make a tea base, like standard kombucha, and bump it up with extra fermentables, though this would be more of a "beer-like kombucha" than a real hybrid. (This is what commercially available concoctions like Mava Roka and K.P.A. do). You could brew a beer, but ferment it with a kombucha mother. You could brew brew and kombucha separately, and physically blend them after the fermentation process, but before packaging. Or you could use pasteurized kombucha as a souring agent to lower the initial PH and add flavor, while still fermenting with standard yeast... which is pretty much what I did, with Belgian yeast and Brett.

Okay, cool, so there are a lot of options... but why? Why not just brew a regular sour beer? Or a regular funky Brett farmhouse ale? Well, if you're researched brewing those two styles of beer, you probably know that sour beer takes a long, long time before it's ready, and Brett beer... well, it's funky, it's tart, but not really sour. Brewers — particularly homebrewers — are always looking for methods to produce a flavorful "quick sour" beer. Half the complexity for half the time seems like a worthwhile tradeoff, if that's what you're expecting. A few months before brewing this batch, I brewed a similar recipe with a lighter malt base and used 15% acidulated malt to add some sourness to it, based on a method used for Ithaca Brute. While of course I didn't know how it would turn out at the time, that batch picked up zero sourness or tartness from the acidulated malt — just a mild, fruity Brett funk. So as I've discovered, acid malt does little to sour a beer (unless, perhaps, you use an extreme percentage), while adding kombucha to a beer at flameout contributes significant sourness. Where that Belgian pale ale was a disappointment considering the time I invested in it, I feel that this one is a pretty unequivocal success.

Brett's Salubrious Tea Party, as I've cheekily named this batch, is perhaps caught in a strange place: not sour enough to be a full-fledged sour ale, but misleadingly sour if you were just expecting some funk. I'm happy with the level of both, seeing as it's just what I envisioned. The funk is evident from the moment you pour the beer, with plenty of that classic barnyard / tart cherry character (interesting, since I used Brett B and not Brett L for this... maybe some snuck in there anyhow?). I was worried this wouldn't be Brett-y enough based on my gravity readings, but once bottled, the little Brett man really stole the show. While I can't say that the kombucha provides any specific flavor, it does add a nice background sourness that's neither so sharp or acidic as to be out of place in a tart farmhouse ale. It's not conventional, but it's not weird, if that makes sense.

Due to its open-fermentation process with constant O2 exposure, Kombucha produces a more much acetic sourness than you'll find in most sour beer styles. The exception is Flanders Red ales, which allow for a bit of vinegary acetic sourness. So for the grain bill, I opted for something a bit darker than your average farmhouse ale, hoping to capture that same interplay of tangy sour and smoothly sweet. I was conservative, though, and the effect isn't entirely there. I believe the complex malt base gave Brett the chance to develop some more complex flavors, so I'm happy I went with it, and wouldn't change the direction of it in a re-brew. There's a solid backbone, but nothing like the sweet/sour interplay in a Flanders. What's more disappointing to me, though, is the lack of head retention — with 2.5 pounds of wheat and some Carared in here, how does the head fade to nothing almost instantly? I've had bottles of kombucha pour with more head retention than this. Oh well.

So how did I add the kombucha? I've been kind of referring to the process as a "Kombucha sour mash," although that implies that I fermented some of the malt with kombucha. Rather, I wanted to keep the two fermentation processes separate from each other. It's hard to say exactly how the weird microbes in a Kombucha SCOBY would react to a malt-base fermentation, and I figured I'd leave that experiment for another time. For this, I wanted to brew a beer with some built-in sourness from kombucha, where Brett and Sacch could then do their thing, funking the beer up over a couple months.

A few weeks before brew day, I made about 1.5 gallons of extra-sour kombucha. At brew day, I withheld 1.5 gallons from the sparge volume and then began the boil as usual. As the wort boiled, I poured the kombucha into a smaller pot and raised it to 160 F, maintaining that temp for 30 minutes or so, which pasteurized the kombucha. (I wasn't sure how boiling would affect the flavor of kombucha, though I'm thinking you might be able to add the kombucha right in with the sparge water. This would allow for better efficiency and even more sourness). As soon as the boil finished, I added the pasteurized kombucha to the wort and allowed them to cool down together. Then, with the kombucha intact but its microbes dead, I pitched brewer's yeast and Brettanomyces, and added 0.3 oz medium toast oak cubes.

As with that Belgian pale ale linked above, I'm not totally happy with the Belgian strain I used to ferment this (Safale's dry Belgian strain), and some more initial character from a saison or Belgian strain might have given the beer more depth. In spite of all the tart fruit flavors, this still finishes relatively clean, with a lingering toasty sweetness from the menagerie of malts. Rather than a puckering finish, there's more of a tannic, slightly bitter quality, which I'm guessing is from the oak. And about that...

I am becoming convinced that oak aging is integral to getting all of the complex flavors out of Brettanomyces. Brett metabolizes some of the sugars present in oak, and combined with the flavors added by the wood itself (in this case: slight tannins, a dry, almost bitter finish, and subtle vanilla / spice), there are a number of dimensions rounding out the beer that I believe really help pull it together, and wouldn't have been possible without the oak. Now, I don't meant to say you can't make a great Brett beer without oak — there are other ways to pull it all together — but in a beer like this, with a heavy focus on flavors that are more aromatic than ingrained, it's a necessary backbone. Without it, you might have flavors that are nice, pleasing, but surface-level, with a beer that just seems sort of flabby and flat underneath. A higher carbonation level is another way to combat this, of course, and this batch could probably used a boost in this regard too, though just slightly.


Recipe-
4 Gal., All Grain
Mashed at 152 F for 70 minutes
Fermented at ambient room temp, ~74 degrees F
OG: 1.050
FG: 1.006

Malt-
#3 Vienna malt
#2.5 white wheat
12 oz Carared
8 oz Munich malt
4 oz Special B

Hop Schedule-
0.5 oz Calypso @20
0.5 oz Calypso @5

Yeast-
Safale S-33 Dry Belgian Ale Yeast
Wyeast Brett B

Other Additions-
Withheld 1.5 gallons from sparge water, accounting for reduced efficiency. Added 1.5 gallons pasteurized kombucha at flameout, let chill to room temp.
Added 0.3 oz medium toast American oak cubes for entire duration of fermentation / aging (~8 months).

5 comments:

  1. This comment has been removed by the author.

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  2. Which Brett strain did you use with this batch??

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    Replies
    1. Wyeast Brett B, as slurry from an older batch I believe. Given the super funky / tart cherry flavors I'm getting though, I'm wondering if some other strains got mixed in.

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  3. Great idea! I've only just gotten into kombucha but this has inspired me to try brewing or blending with it.

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  4. If you really wanted a quick sour, what about combining a sour mash with a kombucha addition and fermenting with sacc? That way you could get lactic and acetic acid. The only thing I would worry about would be the combo lowering the PH so much that the sac would not work. I suppose you could always pasteurize the kombucha and add it to the beer after primary fermentation was done. In This situation would you still use S-33? I did a sour mash BW and used US-05 b/c it is supposed to be tolerant of low PH. Fermented perfectly, but didn't add much character.

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