Beer Education: Foeders and Sour Beer

Amy standing in front of a foeder with a glass of beer.

(Note: This is a modified version of a piece I wrote for the Stormcloud Brewing Co. mug club members.)

What is a foeder?

A foeder, (pronounced FOOD-er) is a really, really large barrel, typically oak, used to age wine and beer.¹ Not only are they for imparting strong oak flavors into the beer, they also allow a slow addition of oxygen into the barrel over time; which changes the profile and flavor of the beer. The shape of a foeder may trend towards ovular or more cylindrical than the standard barrel shape. ²

Foeders have been used in Belgium and other European countries for hundreds of years, and are now growing in popularity in the US in the craft beer community, for sour beer or other traditional Belgian-style beer.

Vintage photo of men standing by an enormous barrel.

Our first foeder was purchased as the next step in developing Stormcloud’s sour program. Sour beer is an age-old Belgian tradition of intentionally introducing microbes (yes, sometimes even ‘wild’ microbes) into the beer to create a variety of flavors – sour, tart, funky, earthy, leathery – and so many more!

We purchased our foeder from Foeder Crafters of America – the only maker of foeders in the United States.³ It was built by hand from American white oak. The wood is air dried and exposed to the elements for 2 years, and once the foeder is built it is steamed for at least a week. Below you can see a photo of our foeder right after it was built, before it was shipped to us.

Stormcloud's first foeder, still at Foeder Crafters of America.

Our second foeder, which has been christened The Collaborator is currently being used for “clean” (not sour) wood-aged beer. As its name implies, these beers will be made in collaboration with other breweries. Our first beer in The Collaborator was brewed with our good friends from The Filling Station Microbrewery (see photo below.)

Brewers from Stormcloud Brewing Company and The Filling Station Microbrewery posing in front of 'The Collaborator' foeder.
From left to right: Stormcloud Cellarman Ernesto Colon, Stormcloud Brewery Manager Mike Sharp, Stormcloud Co-Owner and Head Brewer Brian Confer, Filling Station Head Brewer Andy Largent, Filling Station Assistant Brewer Tommy Hodges, Stormcloud Brewer Chris Schnepf, and Stormcloud Brewer John Moye.

The collaboration beer was a Helles Lager, and the release date has yet to be determined – it all depends on how it ages in the oak and when the brewers taste it and think it’s ready.

Sour Beer

Bon Appétit magazine describes sour beer as “a style loved by brew nerds but easily appreciated by anyone. An acquired taste, but one we think is well worth cultivating.”⁴ I couldn’t agree more, it is certainly a taste worth cultivating! Though I’ll do my best to explain the nuances of sour beer below, talking terroir of beer requires a little more show than tell.⁵ When well made, sour beer can be among the most complex and refreshing of beers, terrific with food and easily pushing the boundaries of what the modern drinker thinks of as “beer.”⁶

Sour beer, put simply, is a sour tasting beer whose flavor is attained by the introduction of bacteria and/or wild yeast.

What's in a name?

Before diving too far in, I want to address the name – SOUR beer. You heard it here folks – NOT ALL SOUR BEER IS ACTUALLY SOUR. Sour beer is an umbrella term that can encompass a spectrum of flavor styles – tart, fruity, red wine-like, funky, sweet, tangy, leathery, citrus…and the list goes on and on. In the modern American brewing industry, there is much discussion about replacing the term or dividing up the general category of sour beer. Jeffers Richardson, director of Firestone Walker’s Barrelworks wild beer facility discusses this by saying “That term, much to my chagrin, is not really instructive. It assumes a beer should be very tart and very sour, and yet we encompass everything. It doesn’t do the category justice.”⁵ So if the term “sour” has a negative connotation in your mind, the first thing to know is that the name sour beer can mean so much more than that.

A Short History

Before refrigeration and our modern knowledge of sanitation, nearly, if not all beer was to some degree sour. This is primarily due to poorly understood, often naturally occurring bacteria.⁷ People usually avoided brewing during warm weather, when the bacteria and wild yeast was even more likely to produce unbearable acidic and vinegar-like flavors. When brewed in the colder seasons intentionally, traditional sour beer styles are usually produced by aging beer in wooden barrels and involve the attempt to control acidity levels and create agreeable flavor.⁶ You can read more about these traditional styles and their history in the next section.

As craft brewing took off in the United States, there emerged a new generation of brewers who aspired to create increasingly unique and flavorful beers. Many of these breweries have taken inspiration from classically sour Belgian styles. Here at Stormcloud we’ve described ourselves “a small brewery crafting ales within the time-honored Belgian brewing tradition of ignoring time-honored brewing traditions” – and this is an excellent way to describe the evolution of sour beer in the US. Not content with mimicking Belgian sour beers, American brewers have started to develop what might be termed “new world” sour beers.⁶ Due to this evolution of the sour beer style, there is no agreed-upon style guidelines and are yet to be classified in any particular category. The Oxford Companion to Beer says that “this, of course, is part of the fun for the brewers who are making them.”⁶

Sour Beer Styles

Berliner Weisse: A very pale, refreshing, low-alcohol German wheat beer with a clean lactic sourness and a very high carbonation level. Referred by Napoleon’s troops in 1809 as “the Champagne of the north.”⁸

Flanders Red Ale: An indigenous beer of the West Flanders region of Belgium. Sour, fruity, red wine-like Belgian-style ale with interesting supportive malt flavors and fruit complexity. The dry finish and tannin completes the mental image of a fine red wine. The beer is aged for up to two years, often in huge oaken barrels which contain the resident bacteria necessary to sour the beer. It is common in Belgium to blend old beer with young to balance the sourness and acidity found in aged beer.⁸

Oud Bruin: A malty, fruity, aged, somewhat sour Belgian-style brown ale. An “old ale” tradition, indigenous to the East Flanders region of Belgium, which has roots back to the 1600s. Historically brewed as a “provision beer” that would develop some sourness as it aged. While Flanders red beers are aged in oak, the brown beers are warm aged in stainless steel.⁸

Lambic: A fairly sour, often moderately funky wild Belgian wheat beer with sourness taking the place of hop bitterness in the balance. Traditionally spontaneously fermented in the Brussels area and served uncarbonated.⁸

Fruit Lambic: A complex, fruity, pleasantly sour, wild wheat ale fermented by a variety of Belgian microbiota, and showcasing the fruit contributions blended with the wild character. The type of fruit can sometimes be hard to identify as fermented and aged fruit characteristics can seem different from the more recognizable fresh fruit aromas and flavors.⁸

Gueuze: A complex, pleasantly sour but balanced wild Belgian wheat beer that is highly carbonated and very refreshing. The spontaneous fermentation character can provide a very interesting complexity, with a wide range of wild barnyard, horse blanket, or leather characteristics intermingling with citrusy-fruity flavors and acidity.⁸

Gose: A highly-carbonated, tart and fruity wheat ale with a restrained coriander and salt character and low bitterness. Very refreshing, with bright flavors and high attenuation. Moderate to restrained but noticeable sourness, although historical versions could be very sour.⁸

American-Style Sour Ales: Style guidelines for American-style sours are intentionally nebulous because American brewers are still rewriting the rules. Many are inspired by traditional sour styles, which are used as a jumping off point to experiment with techniques such as hops additions for bittering and aroma, racking sour beers into freshly used wine or spirit barrels, blending together batches, adding adjuncts, or just about anything else they can think of.⁹

Vocal to Know

In addition to foeder, here are a few other sour beer-related vocabulary that you might like to know.

Lactobacillus & Pediococcus: These are the two main bacteria that contribute to the actual acidity or sourness, in the beer. Skilled brewers of sour beer will blend these bacterial strains carefully, massaging fermentations to create the acid profile they desire in the beer.⁶

Brettanomyces: A wild yeast strain (considered a scourge in most vineyards, though welcomed among many natural winemakers) that is often used in the making of new world sour beers.⁶

Wild Beer: This is an ever-constant debate among brewers, but the term is generally used to describe any beer that displays the earthy characteristics of Brettanomyces yeast strains (or other wild yeast strains), regardless of whether the beer is a light golden ale or a dark stout.⁶

Mixed Culture: Instead of using a single clean yeast strain, brewers intentionally select a combination of different yeasts and often bacteria to work their magic in a fermentation with the goal of creating something new and interesting.¹⁰

Blending: The act of combining two or more beers. Through blending, you can create unique complexity that otherwise you can’t achieve with unblended beer. You can blend a five-year-old version and a one-year-old version of the same recipe for a unique final product, for example; or blend beers made with the same recipe but fermented with two different yeast strains; or blend two or more completely different styles.¹¹

Kettle Souring: (also called quick souring) Souring beer in a steel “kettle” and adding lactobacillus (a bacteria that converts sugar into lactic acid.) While this method is faster and easier than the traditional sour beer method, it loses much of the complexity. ¹²

Spontaneous Fermentation: What happens when a brewer leaves the inoculation (the moment when yeast and bacteria come in contact with the liquid) up to whatever organisms happen to be in the air or on the fruit that they are fermenting.¹³

Coolship: A shallow bed that can be attached to a truck and driven through the surrounding area to inoculate wort with wild yeast.⁵ This past October, we collaborated with Speciation Artisan Ales, brewing wort for their cool ship. (see photos below)

Stormcloud brewing Company Brewers posing with the Speciation Artisan Ales crew and coolship.
Filling a coolship with wort.

I hope this sour beer primer made you excited to join us on our journey through Stormcloud’s new sour beer project, and give the beer we release a try. Each beer we craft is made to be unique, flavorful, and original. You never know what could become your next favorite beer! 


¹ “Foeder (FOOD-er) For Thought!” Dechutes Brewery, 19 Mar. 2015,

² Dykstra, Jim. “What is a Foeder?” The Beer Connoisseur, 8 Sept. 2016,

³ Shaw, Iain. “America’s Only Foeder Crafter Is Changing How We Make and Drink Wild Beers.” VinePair, edited by Erica Duecy, VinePair Inc., 11 Mar. 2019,

⁴ Bernstein, Joshua M. “Sour Beer Primer: How (and Why) to Drink These Funky Wild Ales.” Bon Appétit, Condé Nast, 26 Feb. 2014,

⁵ Roth, Bryan. “A Culture of Confusion — The Process, Vernacular, and Challenge of Selling “Sour” Beer.” Good Beer Hunting, edited by Austin L. Ray, 5 Apr. 2018,

⁶ Oliver, Garrett, editor. The Oxford Companion to Beer. 1 ed., Oxford University Press, 2012.

⁷ DeBenedetti, Christian. “A Brief History of Sour Beer.” The New Yorker, 26 July 2013,

BJCP Beer Style Guidelines. 2015 ed., Beer Judge Certification Program, 2015, p. 44-48.

⁹ Wilmes, Tom. “The Sour Beer Spectrum.” Craft Beer & Brewing, 2016,

¹⁰Janzen, Emma. “Mixed Culture Fermentation Stretches the Boundaries of Beer.” Imbibe, 9 Aug. 2017,

¹¹ Wilmes, Tom. “When to Blend Your Beer.” Craft Beer & Brewing, 2015,

¹² Wolinski, Cat. “The Differences Between Sours and Kettle Sours, Explained.” VinePair, edited by Erica Duecy, VinePair Inc., 18 May 2018,

¹³ Delany, Alex. “What Is Spontaneous Fermentation, and How Does It Affect the Taste of Wine, Beer, and Booze?” Bon Appétit, Condé Nast, 16 Aug. 2018,

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