While this beer is technically an Oatmeal Stout, it’s far from your traditional bowl of porridge.
When starting Du Cane Brewing, founder Will Horan aspired to create a stout-exclusive brewery. Two years, two pale ales and a pilsner later, this is the first stout to be released under the Du Cane name. With this first stout however, he decided to make it a little bit special and use an ingredient close to his heart.
“A lot of brewers have a soft spot for a certain speciality malt or other ingredient and right back to when I started homebrewing mine has always been oats,” said Will. “In any style I love the subtle flavour and texture it brings.”
The beer pours from the can with a deep black hue and instantly brings a rich, roasty aroma. Despite sitting at 50 IBU, the first sip is supported by a pleasant warmness and a gentle smoothness. This delightfully smooth body makes the beer unbelievably easy to drink - a dangerous feature considering the 7.4% ABV. But what exactly makes this beer so smooth?
When I think of oats, the first image that comes to my mind is often a bowl of thick porridge. This thick, gluggy consistency is caused by the high levels of gums found in oats. These gums are made up of (1,3;1,4)-β-D-glucans, which are glucose sugars linked together into long chains or polymers. β-glucans are also found in barley grains, however, enzymes produced during the malting process break these chains down into smaller fermentable sugars for the yeast to use up. As the oats are added during the mashing step, which is typically at higher than ideal temperatures for the appropriate enzymes, many of the oat beta-glucans persist. When added to a brew, these gums increase the viscosity, bumping up the body and leaving the beer with an elevated smoothness. Oats have also been found to improve yeast growth, head retention and the general stability of a beer - no wonder Will has a soft spot for oats.
Higher levels of β -glucans in a beer typically leads to improved mouthfeel, a well sought-after and difficult to describe characteristic. One study found that adding just 10% oats to a mash boosted the beta-glucan levels from 20 mg/L to 393 mg/L. β-glucans not only benefit the beer but also our gut health. These polymers are soluble dietary fibre, which have been shown to lower cholesterol and improve blood sugar levels and digestive health.
So why aren’t brewers adding oats to every brew? Just like in your porridge, the oats form a thick gelatinous mash. One big issue is that the increased viscosity can lead to issues with the brewing process, including stuck sparges and slow transfer times. Du Cane’s Oatmeal Stout features a generous 20% rolled oats which is enough to make most brewers tremble. To deal with the high β-glucan levels and “gumming” of the mash, Will used rice hulls (the outer husk of a rice grain) to improve the filter bed of the mash. Despite this, they still experienced a few issues with Will commenting that “it was a long brew day with an extremely long run-off and sparge, probably because of the sheer volume of the mash and the surface/weight ratio of the screen in the bottom of the mash tun.”
Let’s hope that the long brew day hasn’t deterred Will from his favourite ingredient though, as we can’t wait to see more oatmeal-backed brews from Du Cane Brewing.