Leah’s Beer School: Lesson 27

What is a foeder?

Foeder (pronounced “FOOD-er”) is the Dutch word for a large vertical or horizontal oak vessel in which beer is fermented. The distinction between a barrel and foeder is somewhat discretionary, but as a general rule foeder capacity starts at 600 litres or roughly three times the size of a regular wooden barrel, where larger tanks can hold thousands of litres of liquid. The world’s largest foeder in Byrrh, France, although no longer operational, once held a maximum capacity of one million litres.

Barrels versus Foeder 

Foeders were originally used to store wine, but have more recently gained momentum in the craft beer industry to ferment clean lagers, sours and other mixed fermentation ales. Compared to foeders, barrels have a higher surface area to beer volume ratio, allowing for more oxygen to seep into the beer. Increased oxidation accelerates the aging process which may lead to over-acidification. A foeder, by contrast, has a lower surface area to beer volume ratio and a gentler ingress of oxygen. They allow for a slower aging process than barrels, which can be easily and consistently monitored with a tasting valve.

All Shapes and Sizes 

Not only do foeders vary in size, they vary in shape too. Peter Bouckaert of Colorado’s New Belgium Brewing Company describes the difference between an upright flat top foeder versus an egg-shaped horizontal one. In a flat top, even a little bit of evaporation allows for a lot of oxidation, which is the perfect environment for acetic-acid producing bacteria and ideal for making highly acidic styles, such as a Flanders Red or Oud Bruin. In an egg-shaped foeder, a small amount of evaporation will barely touch the crest of the oval leaving less headspace and therefore less exposure to oxidation and acetic acid. This style of foeder is perfect for mixed-fermentation ales and cleaner beer styles that require a more delicate maturation to impart subtle wood flavours and characteristics.

Wine Foeders v Beer Foeders 

Repurposing a foeder originally used for wine or spirits, also means inheriting all of the flora (yeast and bacteria) of the wood, and is a much more economical option than a custom-made one. A newly constructed foeder is a major investment, but it has the distinct advantage of allowing for greater control over the size, shape and characteristics of the wood.

Brewing a foeder beer is truly a labour of love, as it is an incredibly expensive and time-consuming endeavor. The greatest advantage of foeder-aging is that it has allowed brewers a greater degree of control and consistency in creating some incredibly complex and flavourful beers. Any type of barrel aging, whether large or small, requires an extraordinary amount of skill, patience and determination. So, whether you like lagers, sours or stouts, there’s a foeder-aged brew made perfectly for you.

(Leah is a Toronto based freelance writer as well as Head Beer Weenie and a server at C’est What)