Thornbridge Brewery – Between The Sheets
8.3% Double Stout Aged in Rum and Cognac Barrels
Producing barrel aged beers is always a pleasure that gives brewers the opportunity to experiment with otherwise unachievable flavours. The time involved with slow and gentle ageing in an oak cask can produce some fantastic improvements to the right kind of beer. That same time will often ruin styles that are designed to be drunk fresh. Hoppy pale ales will only diminish as the oxidation that occurs will remove positive flavours and introduce cardboardy notes or, perhaps worse, dull the beer to being just average.
With this in mind, we decided to brew a strong, rich stout that closely resembles a classic Thornbridge beer, Saint Petersburg. Brewing with plenty of chocolate and roasted barley malt gives the beer a black appearance and contributes coffee and chocolate flavours as well as providing anti-oxidants that help a barrel aged beer weather the storm in oak for 9 months. Brewing with a high bitterness of 70 IBU (International Bitterness Units) allows for some drop off during ageing as well as being a great protector to any unwanted bacteria that might survive in the cracks of the wood.
Regular tasting through a hole made by a nail driven into the head of the barrel lets us monitor changes as the beer succumbs to micro-oxygenation that softens bitterness, rounds out flavours and can bring once clashing elements into harmony. Where time is the enemy of hoppy pales it can bring new positives to a dark stout.
By splitting the beer into both Rum and Cognac barrels we can then decide on a suitable blend and also pick out our favourite barrels that might end up being ‘tested’ a little more frequently than others. Such is one perk of being a brewer entrusted with barrel ageing. Once blended back together in a tank we can gently carbonate to a lower than usual level to let the beer be silky smooth.
After 3 weeks in the brewery, followed by 9 months in oak, we have achieved what we set out to when creating a recipe set for barrel ageing. Black in colour with a creamy tan head, the sweetness of rum and cognac have balanced with the bitterness of the hops and roasted malts. Caramel, vanilla and a touch of tobacco on the nose give a distinctly barrel aged aroma that has plum, apricot and treacle following. An initial alcohol and spirit sweetness leaves for flavours of bitter coffee, dark brown sugar and a surprisingly light palate for a beer over eight percent. The beer finishes with a clean, coffee-like, drying bitterness with a hint of sweet orange.
The cocktail of the same name is thought to have come from a bar in Paris in the 1930s, or possibly was created in the early 1920s when drunk as an aperitif when inside a brothel. We would probably recommend a slice of dark chocolate cake or some aged cheese instead.
Ben Wood, Technical Brewer.