Lost, Stock & Barrel: The Forgotten Funk of Old Ales

It was once indispensable to their refined character, but Brettanomyces is rarely involved with oak-aged barleywines these days—and that’s not all they’ve lost since the 1800s.

Jeff Alworth Jun 8, 2022 - 11 min read

Lost, Stock & Barrel: The Forgotten Funk of Old Ales Primary Image

Hops going into a barrel of stock ale at Epochal Barrel Fermented Ale in Glasgow, Scotland. Photo: Courtesy Gareth Young of Epochal.

In the final quarter of the 19th century, no one in brewing was doing more cutting-edge research than Carlsberg.

In 1883, Emil Hansen isolated pure yeast strains there. In 1909, S.P.L. Sørensen developed the pH scale. Between those landmarks, in 1903, the researcher Niels Hjelte Claussen peered through his microscope and made his own discovery: a type of yeast cell distinct from the kind that made Carlsberg’s lagers and one responsible for the “peculiar and remarkably fine flavour” it made in the beer from which he cultured it.

That beer was an English stock ale, also known as old ale or barleywine. To honor the beer’s origin, he named his discovery the “British fungus”—Brettanomyces.

In later research, Claussen tried adding the yeast to his lagers, with poor results. He also tried brewing strong, English-style beers using just Saccharomyces but found that they “lacked the English character.” At the turn of the 20th century, as Claussen was unlocking the secrets of why strong British beer was so special, he came back to the yeast he identified.


It was essential to the flavor profile of these legendary beers.

A Forgotten Tradition

For hundreds of years, strong, vat-aged British beer had been the most prized in the world, traveling in the bellies of ships bound for Boston, the Baltics, Bombay—and points all over the world. Over those centuries, brewers knew vat aging was essential, but Claussen’s discovery helped explain how. In the technical paper announcing his discovery, he concludes, “it is evident that the secondary fermentation effected by Brettanomyces is indispensable for the production of the real type of English beers.” (He even italicized his conclusion for emphasis.)

Unfortunately, Claussen’s discovery arrived at a moment of seismic change, when technology, war, and the rising popularity of lagers would conspire to end the era of vat-aged, Brett-kissed stock ales. Despite the revival of wild ales—these days associated far more with Belgium—strong English ales of mixed fermentation now seem out of place, or out of time. Inspired by their historical fame, breweries occasionally create revivals, but these often seem strange and foreign to modern palates.

For anyone who likes to imagine standing in a 19th-century London warehouse, marveling at creaking oaken vats the size of small houses, this is a shame.


Perhaps fashion has just passed us by—or could there be another explanation?

Contemporaneous accounts of these beers litter the historical record. These were vatted strong ales sold under various terms, and attempts to differentiate among stock ale, old ale, and barleywine, for example, are more modern fetish then historical practice.

Writing in 1890 about Colne Spring Ale, an aged barleywine, Alfred Barnard describes it as “full flavoured, soft, creamy yet vigorous.” Comparisons to wine or sherry were common; indeed, British drinkers sipped these beers from cordial glasses in periods when high taxation made European liquors expensive. They were beers fit for the gentry, in the United Kingdom and abroad. Rarely has beer been seen as a fine spirit, but vat-aged British beers were—all of which makes their disappearance more curious.

I spoke to a few brewers, mostly abroad, devoted to reviving these beers. In their study, they’ve discovered that the old breweries made them using techniques lost to modern brewers.


So, maybe these beers aren’t just weird and unfashionable. Maybe brewers have just forgotten how to make them properly.

Relearning Old Lessons

In Manchester, England, Steve Dunkley founded his tiny Beer Nouveau brewery in 2014 with an eye toward reviving old beers.

When it comes to English old ales, Dunkley believes their character depended on malts that are no longer commonly available. Modern malts taste great with Saccharomyces, but once they go into a vat, Dunkley describes them as flat and “dusty.” He prefers heritage grains.

“You can take something like Maris Otter, and it’ll give a decent amount of flavor, but Chevallier and Long Eared Nottingham will give so much more.” That’s especially true if they were kilned using techniques typical of the time, as Dunkley has found with Chevallier malt kilned to old specifications. “The flavor profile from them is something else, so smooth and rich, and it balances as well as enhances the leather notes from the Brett.


In London, James Atherton also uses heritage malts to make mixed-fermentation revival ales at his Beerblefish brewery. Heritage ales from the 19th century are at the center of Beerblefish’s lineup. In New Zealand, at North End Brewery in Waikanae, Kieran Haslett-Moore made a revival barleywine to honor his father who had recently died. He went a step further in preparing the wort by boiling it for 12 hours, turning his pale liquid a mahogany brown.

In 19th century Britain, as today, Saccharomyces was the workhorse. These yeast allow ales to be served fresh in a short period of time. Back then, if the beer was bound for vats, it would arrive fully fermented. For brewers working with vat-aged beer, “cleaning” it was an important activity.

Before starting Epochal Barrel-Fermented Ales in Scotland, Gareth Young was a philosophy lecturer at the University of Glasgow. He has an appropriately academic approach to old Scottish-style ales. An important piece of equipment in old breweries was a “cleansing tank,” which scrubbed the fresh beer of yeast. “This gives a cleaner funk,” he says. “Less ethyl caprylate, for instance.” That ester contributes sweet notes that can smell like fruit brandy.

At Beer Nouveau, Dunkley cites a different kind of “cleaning” that’s important for refining these beers: Brettanomyces, like lager yeast, needs to go through a full cycle. Those aggressive, funky flavors we typically associate with Brett “are there because the yeast hasn’t finished and hasn’t cleaned up after itself. Once it has, you get wonderful new soft leather notes from it.”


In his own research on Scottish brewers, Young found that they commonly added hops to their vats during maturation. In such an arrangement, two things would be very familiar to any modern brewer: hop creep and biotransformation. “Hop creep helps make unfermentable sugars fermentable and feeds them to the Brettanomyces, which in turn dries out the beer and gives very high carbonation in the cask,” he says. At the same time, the yeast activity transforms hop compounds to produce more intensely fruity aromas. He isn’t sure how well brewers back then understood the effects, but these were functional parts of healthy conditioning.

Young says that brewers did understand that the transformation came from yeast—and that was long before Pasteur described the precise biological process. Decades before Pasteur’s findings, brewers wrote that if the beer wasn’t maturing properly in the vats, the cure was removing dregs from healthy lots and adding them to the anemic ones. “So there was deliberate pitching of Brettanomyces long before they had a name for the microbe,” he says.

The flavors that marked stock ales of past centuries lacked many of the problems that can trouble mixed-culture brewing: excessive acetic acid, intense funkiness, chemical off-flavors. Instead, using what we would now call “heritage” barleys, techniques like long boils, cleansing tanks, and dry-hopping, brewers are edging back toward the refinement for which old stock ales were renowned.

The Revivals

In the past decade, these brewers have gone deep into ingredients and technique to make fascinating examples of old stock ales. Haslett-Moore made his West Moon Old Ale with yeast cultured from a 1977 bottle of Bass Jubilee Strong Ale. Bass, of course, was the most famous of the old English barleywines, and the beer its yeast created was worthy of the heritage. “Alongside the big malt character and sherried positive oxidation character, it is a full experience,” Haslett-Moore says.


Just north of Watford, Pope’s Yard Brewery is home of Colne Spring Ale, one of the most famous classic barleywines.

Geoff Latham grew up in Watford and watched the brewery that made the beer, Benskins, shutter in 1979. He has worked to revive Benskins’ most famous ale, speaking with people who worked there and piecing the process together. “It was via one of them that I learnt … the details of everything from the settings of the rollers on the malt mill to the liquor treatments, mash temperatures, and sugars used,” he says.

Besides strong ales such as Colne Spring, Latham also makes aged “keeping” porters. Beerblefish, Epochal, and Beer Nouveau all have versions of revival ales they have slowly refined as they learn more about how 19th century brewers made their stock ales.

These brewers appear to agree on these points: Their predecessors were well aware of what they were doing and what worked—and those lost beers deserved their fame.

Dunkley leaves us with this comment—a great place to start for anyone peering into history for lessons. “Beers of this era were a lot better than we might have initially thought,” he says. “Brewers knew a lot more than we give them credit for. And we really ought to read some history books before we set out to reinvent the wheel whilst shouting loudly on social media that we’re being innovative.”