A Disquisition on the Nature of Sour

I'm not totally sure why tastes are broken down into just five categories (salty, sweet, sour, bitter, and umami), but what's interesting is that two of the three most characteristic beer flavors--sour and bitter--are considered "aversive." That is, they are signals our ancient adaptive brains recognize as containing potentially lethal substances. These categories of taste are subjective and culturally specific. So much of the terrain of flavor exists well outside their small purview--but somehow they persist.

One of these flavors is the subject of today's post: sour. What is sour, and when should it apply to flavors found in beer, and particularly, should we consider brettanomyces-inoculated beer sour? The answer is semantic, not scientific, but that's fine: it's best to have a shared vocabulary in discussing the flavors present in beer. Back when I reviewed this year's Dissident, I classed it as a sour beer, and Ezra took issue with this. A few weeks ago, the Brewers Association signaled they were in accord with Ezra's view and split brett-inoculated beer off from the category of "sour." And then last week, when I was chatting with John Harris, he also made the point. So, what's sour?

The Nature of Sour
What we call "sour" is the perception of acids. Vinegar, is a great example; it takes most of its sour quality from acetic acid, but also has small amounts of citric acid and tartaric acid. In beer, lactic acid is a big player in the perception of sourness. Impressionistically, it's that puckery quality. Linguistically, there's no precise distinction between "tart" and "sour," though beer people will typically ascribe to more lightly-soured beer the adjective "tart." I'm cool with that.

The Nature of Wild
Wild ales almost always produce sour flavors, but they usually produce lots of other flavors, too. Many of these are referred to by similarly wild-sounding adjectives: horse-blanket, zoo-like, goaty, sweaty. Other qualities seem to come from chemistry labs: nail-polish remover, paint thinner, etc. Still others are less precise--dusty, austere, hot, sharp, funky, tangy. The process of fermentation produces lots of chemical by-products, and no doubt a sophisticated lab could identify all the compounds that produce these varying flavors. Some are related to sourness, some are miles away. I have been lax about using the words "sour" and "wild" interchangeably, and this definitely confuses matters. If a beer is zoo-like, it's best not to refer to it as sour.

Is Brettanomyces Sour?
So then we come back to our friend, brett. Many of the qualities it produces aren't traditionally sour. But it can produce sour notes. At halftime of the Super Bowl, we cracked a Billy the Mountain--a beer soured with brettanomyces clausenii. (The Packers were ahead and I wanted to celebrate while we had the chance--no waiting until the end of the game for this pessimist!) And yes, it is sour--or at the very least notably tart. In fact, the signature quality the brett contributes to the Billy the Mountain is tartness/sourness (though there are other, more subtle harmonics, that figure in). This isn't always the case--this year's Dissident, for example, has many wild qualities, but its acid is less sour than dry and leathery. One of the by-products of brettanomyces is acetic acid, though it doesn't always crank it out in huge quantities. Beers made with brett can therefore be sour or not. They are the chimera of the sour world.

The upshot to all of this is that I feel suitably chastened about my cavalier substitution of the word "sour" for "wild." As a matter of coming to shared vocabulary, using the word sour should be restricted to flavors that are, in fact, sour. On the other hand, it is not strictly true that brett beers are not sour, either. (Claiming they're just "tart" is a scoundrel's refuge.) This is especially true when we're trying to come to shared vocabulary. Compared to standard beers, something like Billy the Mountain has to be considered sour. It's an abstraction to exempt it because the sourness is lighter, different, and more subtle than in other soured ales--and to the average beer drinker, a bizarre elision.

In conclusion, to the question "are brett-inoculated beers sour?" we must agree to the answer "yes." And "no." Thank your for your attention.

Something Wild in Deschutes Brewery

Yesterday, Deschutes posted a most interesting explanatory note on their blog:

We have detected in our lab a similar condition to The Abyss 2009 where some (not all) of the bottles have brettanomyces in them. It is interesting in that there seems no way to tell short of general tendencies in storage conditions where the brett will develop to sensory detection levels.

This is a fascinating situation. A huge percentage of breweries have now moved toward barrel-aging programs, and Deschutes' experience may be the tip of a big, sour iceberg. Wood is a fantastic material for aging beer. Casks breathe, and they contribute tannins and, if they have recently been used for wine or liquor, flavor and aroma from those substances. But porous wooden barrels are also, of course, a marvelous habitat for wild things. Yeasts and bacteria inhabit the cracks between staves and even the tiny fissures in the wood itself. This is exactly the reason American breweries abandoned them in the first place (despite claims of "beechwood aging"). Stainless steel, properly cleaned, harbors no foreign creatures.

I haven't done a proper study of this phenomenon, but my sense is that first-generation wooden barrels are mostly pretty sterile. These are the juicy casks that contribute so much wine or bourbon character to beers. But left for further cycles of aging beer, they become susceptible to contamination. Ron Gansberg discovered a rogue barrel that had turned from among his collection (to his eminent, brett-hating credit, he released that beer for the brett fans before removing the barrel to a secure destruction site). Lompoc had a pinot barrel go sour and it made the single best pour I've ever had from the brewery. And now Deschutes has some funk running wild.

This will be a challenge to breweries who want control over their beer. Mirror Mirror and the Abyss were conceived as high-gravity beers that would age gracefully and allow the notes to commingle over time. The kiss of brett will take these beers in totally unpredictable directions. Personally, I love the idea of soured Mirror Mirror and Abyss. Neither of these is among my favorite Deschutes beer, but soured versions? They would instantly be hugely attractive.

Historically, all beer was aged in wood. The old ales and strong ales meant for aging would all have been infected. This was where the historical distinction between "mild" beer and aged beer ("old," "stale," "stock," etc.) came from. Mild meant sweet and fresh. Older beer had that dry, sherry-like finish of infected beer.

Deschutes' solution is to pasteurize bottles the wood-aged portion [see comment from Gary Fish below] of the beer in Abyss and Mirror Mirror after they exit the barrels. (They'll also arrange for shipment and refunds of returned bottles of soured versions, too. Or, you could give them to me. You know, either way.) I guess that's a good solution for keeping the beers as Larry Sidor and his team envisioned. But there are lots of possibilities here. Deschutes could release unpasteurized bottles in small lots to folks who hope for the tang of brett. Or they could actively encourage their brett populations and produce traditionally soured old ales. Old British breweries commonly blended their lots to produce different versions of beer. Publicans would mix old and mild beers at the bar. Possibilities abound.

It's a brave new world, and breweries with barrel houses are about to discover that they have sour programs under way--whether they intended them or not.

Lisa Riffs on Women and Sour Ales

Last week, I posted a sort of random ramble (my forte) about sour ales and noted, off-handedly that "one hopeful sign is that women seem to like sour ales more than men." Lisa Morrison, a beer-loving woman, has taken this up in less-random fashion:

There is a school of thought that women’s palates are more fine-tuned to bitter (not sour) flavors because, as the primary child caregivers, at least historically, women would often taste food first before giving it to their child. In fact, these earlier females probably even chewed the food a bit before giving it to the younger ones – especially in the days before cutlery and CuisineArts....

But sour, now that is the flavor of unripe berries and other fruit still on the vine or tree. Cavewoman might not have had the luxury of letting those fruits ripen a bit more before eating them or feeding them to the kiddos. Women’s brains developed to not give us the “danger” signal with sour flavors like it did with bitter

This seems right. It does, however, raise another, related question: are hops actually bitter? This is a question I've been turning over in my head a lot lately, particularly after having a bottle of Widmer Deadlift and a pint of Double Mountain Porter A Go Go. We call them bitter, but the bitterness isn't exactly like the bitterness you get from, say, dark chocolate.

But I digress. You should go read Lisa's post in full.

Your Opinion of Sour Ales

This morning's post has produced more interest in the topic of sour ales than I expected. And now I'm wondering--maybe there's more interest in sour ales than I realized. (And maybe all my friends are a bunch of unreconstructed hop-heads.) So, since everybody loves a poll,* here goes:



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*Except for those of you who really, really hate them.
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Will Americans Drink Sour Ales?

I was trawling the internets this morning looking to see what the beer news o' the day looked like, and saw announcements for three new beers at Beernews. Two are sour ales, and at least one was soured with brettanomyces. Personally, I think the trend is fantastic; if some cataclysm reduced the world's beer supplies to sour ales, I'd live a happy life. But I wonder--is anyone actually drinking this stuff?

There's clearly a niche market for sour ales. When New Glarus released their soured fruit ales 15 years ago (ish), they were received with joy. As more breweries joined the party--though not until probably a decade after New Glarus, at least in any numbers--the sour-fans were yet more joyful. There are just enough of us to keep these small runs going.

Yet when I try to propagate the wild yeasted beers, I hit a brick wall. More than any other type of flavor, it seems that if a person doesn't like sour from the outset, he's never going to like it. (They may grow to admire well-made wild ales, but they'd never buy one for the pleasure.) Based on my very unscientific observation, maybe one in twenty people take to sour ales. And this is among beer fans.

One hopeful sign is that women seem to like sour ales more than men--and there's lots of growth potential there. Many of these beers are cuisine-friendly, and may curry some favor with the foodie set. So maybe there's hope.

BeerAdvocate currently lists 184 beers in the "American wild ale" style, which is a phenomenal number. I just wonder--a building trend, or a flash in the pan?
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What Sours a Beer?

In yesterday's post about Devil's Kriek, Samurai Artist sparked a conversation about the souring properties of brettanomyces. Since sour beers are becoming more common, it's a timely discussion. Sourness may be tart and clean as in a Berliner Weisse, dry and austere as in some lambics, our face-puckeringly intense, as in some Flemish reds. These different qualities come from different microorganisms, and it's worth spending a post mentioning a few of the biggies.

My source material here is Jeff Sparrow's Wild Brews, which I recommend highly for anyone interested in a deep understanding of sour beers. Let's start with a pithy opening from the start of his fourth chapter, "Beer-Souring Microorganisms." Here, he describes the actors that create the funk:

"Four dominant types of microorganisms commonly ferment and acidify wild beers: brettanomyces, lactobacillus, pediococcus, and saccharomyces. Sever other important players also merit a mention, including acetobacter, enterobacter, and various oxidative yeasts."

Now, in this next pithy passage, he describes the particular nature of the funk those actors produce:

"The acids most important to wild beers include lactic and acetic acid. Acetic acid, present in copious amounts in vinegar, is sharp, pungent, and greatly increases the perception of sourness. Lactic acid, found in spoiled milk, is less objectionable and contributes a 'tangy' character, sometime perceived as 'sweet' by brewers in contrast to other acids."

(There are actually a host of other acids that contribute flavor like caproic acid, which Sparrow says gives a "goaty," "sweaty," or "zoolike" character. But you can read his book if you want the full monty.)

Brettanomyces
This wild yeast inspires the most awe and fear among brewers. It will eat anything, including dextrins and sugars that other yeasts find unpalatable, achieving nearly 100% attenuation. (Brewers joke that it will start eating the glass in a bottle if you leave it long enough.) Attenuation is the percentage of available sugars a yeast will eat. Wyeast's Northwest ale yeast, a non-brettanomyces yeast, attenuates at about 70%, for example. Brett will produce both acetic and lactic acids, but the former only under certain circumstances. There are at least five species of brettanomyces and many strains within each. The most common is brettanomyces bruxellensis, named for a strain from Brussels.

Lactobacillus
Lactobacillus is a type of wild yeast bacteria that gives Flanders beers (red and brown) their character, as it does to some German ales like Gose and Berliner Weisse. It is not a major player in lambics, however--the lactic there comes from pediococcus (see below). As the name suggests, lactobacillus produces lactic acid. Lactobacillus is far more finicky than brettanomyces, preferring warm temperatures, a low-oxygen environment, and low levels of hop acids.

Pediococcus
As alluded to above, pediococcus is the beastie that gives lambics their lactic, not lactobacillus. This is mainly a function of the life cycle of a lambic. Pediococcus ferments in beer with little or no oxygen; likewise, it gives off no carbon dioxide. In a lambic, the pediococcus kicks in after 3-4 months when, fascinatingly, the wort is exceptionally sour as a result of early enterobacter production. The pediococcus begins when the lambic warms up, creating "long strands of slime" on top of the wort. You can drink the beer at this stage, but it's oily and known as the "sick" stage. But from the sickness comes the lactic, and eventually, the slime is reabsorbed as the brettanomyces begin gobbling up everything that's left.

The upshot? "Sour" isn't a fixed flavor. Different beers have different compounds and acids that contribute characteristics that define style. Brewers have very different attitudes to the kinds of sour beers produce. When I was at Allagash last year, Jason Perkins and Rob Tod described their efforts to cultivate native brettanomyces. On the other hand, Ron Gansberg doesn't want brett in his brewery; he's a lactobacillus man. Matt Swihart is a brett man, but is he only a brett man, or will future batches exhibit the character of other funky bacteria? I guess we'll have to wait and see.



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PHOTO: Cantillon casks, Thom's Beer Blog / link

Update.
By the way, Sparrow reproduces a lot of very cool graphs he got from Raj Apte, and you can find those at his site. One I particularly enjoyed is a graph showing the waves of activity in lambic fermentation, particularly in the first year. Click on it to see an enlarged version. You'll find more cool stuff if you follow the link to his site, too.

Double Mountain Devil's Kriek

Beer is local. Or was, anyway, before industrialization. Styles emerged from available ingredients, local culture, weather, water--a host of circumstances. The Zenne Valley is reputed to be so hospitible to spontaneous fermentation because local fruit trees (now mostly gone) housed tasty wild yeasts. The monks of Abbaye Notre-Dame de Saint Remy brewed beer in the sixteenth century from barley and hops grown on abbey grounds. Bohemian pilsners and West Coast pale ales wouldn't be recognizeable without native hops. But then the industrial revolution made it possible for breweries to receive ingredients from thousands of miles away; its arrival meant the loss of indigenous styles and the homogenization of national brewing.

But now we are following our tracks backward, and that's what makes Double Mountain's Devil's Kriek experiment especially exciting. Made with cherries grown in brewer Matt Swihart's orchards, they return us to that time of specific locality. A kriek with Rainier cherries?--must be from the American Northwest. Ah, but the experiment also shows the drawbacks of depending on specific crops. Limiting yourself to a single orchard means living and dying by the vagaries of your fruit. Forget consistency; like wine, each year's kriek will exhibit the qualities of the cherries. Some will be better than others, and people who admire the product will admire this variability.

About seven thousand people showed up at Belmont Station on Friday to get a glass of the '09 vintage (made of '08 cherries), and I was among them. (The line was seriously insane, stretching out the door and down the sidewalk to the corner. Fortunately, we got there by 5:50 and beat the worst of the crowd.) Here's what I thought.

Devil's Kriek
Although I got the lowdown on the beer from Matt Swihart at Belmont Station--he was there handing out cherries from his orchard--he actually blogged about the brewing process on Friday.

"The base for our Krieks is a blend of three batches of a strong golden-colored beer, each fermented with a different yeast: our house ale yeast, which is of Belgian origin; our house Kölsch yeast; and the notorious wild yeast Brettanomyces. We’ve used Brettanomyces before, in the Red Devil, the IRB and in last year’s Devil’s Kriek. “Brett” contribues subtle fruitiness and barnyard character (think of smells in an old barn on a cold day) at low-level intensity and a horse blanket character (think of smells in a horse barn on a very hot day) at high intensity. Brett is also a component of many spontaneously-fermented French wines, as has legions of both fans and detractors in the winemaking world.

"Devil’s Kriek was held on the cherries for 9 months, then transferred and stored cool at 34F for the remaining 3 months. The Rainier Kriek sat on cherries for the entire 12 month process at cellar temperatures ranging from 50F to 75F. The warmer ferment on the fruit allowed the Brett to assert itself more fully, driving the acidity lower and kicking out a stronger wild-yeast character. We brewed 20 barrels of Devil’s Kriek in a regular fermenter, along with 3 barrels of Rainier Kriek in a mobile mini-fermenter that was originally in service as a yeast propagation tank at Widmer."

The beer is a massive 9%, similar to the sours Ron Gansberg brews--a decision I don't fully understand. Most of the Belgian sours, and particularly the fruit lambics, run about 5%. In my experience, this allows the more subtle and volatile essences of the fruit to express themselves. The force of flavor is in no way diminished in beers of even 4% or less; and unlike other elements of beer, sour doesn't depend on alcohol or malt. Of course, Gansberg's 2008 Apricot Ale had one of the most lush aromas I've ever encountered, and he uses a tripel as his base, so maybe I don't know what I'm talking about. (And wouldn't that be shocking?)

As you can see in the photo, Rainier Kriek drew very little color from the fruit; it's also a lot cloudier than the Devil's, which had a pinot-like clarity and depth of hue (though the color's all bing). Mostly the Rainier Kriek was characterized by sourness--if the cherries contributed anything, it was just at the threshold of identification. (This isn't too surprising--Rainier cherries are in no way assertive. They have a gentle cherry flavor but mostly a neutral sweetness. Cherries for people who don't like cherries.) The sour was lovely, though. I asked Matt what strain of brettanomyces he used and whether it was some kind of mild strain. (No.) Brett can get pretty funky, but not here. I found it gently sour and almost a little salty. Somehow it retained some residual sweetness, too, and the body was thicker than I expected from a brett-soured ale. A nice, quaffable beer, if such a thing can be said about a 9% sour ale. Call it a B+ on the patented rating scale.

The Devil's Kriek has a candy nose with an undercurrent of chocolate and almost no sour. The flavor is surprising; as in the nose there's almost no sourness. Instead the fruit contributes the beer's two main notes, a subdued cherry and a bitter, tannic note that I assume came from the pits. As it warms, the bitter note diminishes and a bit more of the cherry comes out. Appropriately, it's fairly dry and not at all cloying--the brettanomyces have taken care of any stray sugars that might have been floating around. I suppose you can intuit the size of the beer by the mouthfeel, but the alcohol isn't especially obvious.

"Not especially obvious" could be the three-word bullet for Devil's Kriek. It's a subtle, refined beer, and toward the end of the glass I was appreciating its wine-like character. But since I had the 2008 version in my head--I recall a tour-de-force of both sour and cherry intensity--I found it a bit underwhelming. Call it a B-.

Based on my discussions with Ron Gansberg, fruit is hard to work with. If you're not a tinkerer, forget it. My guess is that Matt is already adapting. He said he'll leave this year's fruit on the tree for a couple weeks longer so it ripens more. This should give the beer a more intense cherry flavor and allow him to take the fruit off sooner so it doesn't extract as much from the pits. But of course, that's if the fruit cooperates.

Still, I encourage everyone to track this beer down and have a glass. There aren't very many products like it in the world, and it's a rare treat to have a local brewer willing to put this much time and effort into any beer. Give it time--in a few years it could emerge as an Oregon classic. Plus, you need to fix it in your mind so that next year you have a basis for comparison.