These two beers started from the same mash, I pitched the same microbes (White Labs WLP665 Flemish Ale Blend, and dregs), and aged them in two third-use barrels from Balcones Distilling for four months. While most of each batch then went onto fruit (raspberries for the rum, cherries for the malt whisky) I reserved a gallon of each fruitless to taste the base beer. While I love fruited sour beers, I’m usually far more interested in the straight-up examples. They provide a truer expression of the magic of microbes, barrels, and wort!
Rum Barrel-Aged Sour Brown
Appearance – Clear, mahogany leather, dense off-white head.
Smell – Madeira-like, brandy-soaked raisin aromatics with a touch of oxidation. A brighter fruit candy note as well – SweeTarts perhaps. A tinge herbal as well, not what I usually pick-up in an old/dark sour.
Taste – Flavor leaves those darker fruit flavors behind for cherry-acidity flowing into cocoa powder. Dry, but still enough to support the malt and oak. Not distinctly rummy to my palate… but in comparison to the whisky-barrel it is surprising how much of that fruit is from the barrel!
Mouthfeel – No tannins or anything rough. The acidity helps to cover-up the lean body.
Drinkability & Notes – Somewhere in the nebulous realm between old ale and oud bruin, with the barrel playing a wonderful supporting role. While I enjoyed the jammy raspberry contribution, I'm glad I also got to taste all the nuance here that was obscured by the fruit.
Malt Whisky Barrel-Aged Sour Brown
Appearance – A twin, other than the slightly stickier head.
Smell – A cleaner more fresh-brown-liquor aroma. What I thought at first sip was dark fruit from the combination of fermentation/age/malt really seems to have been coming from the rum barrel. This one is more dusty-basement damp-oak. Coconut candy bar.
Taste – Acidity is tamer, but still firmly sour. The fruit is more plum than cherry, not as bright. The finish is a bit curdled milk, lingering in a not-entirely pleasant way. Likely more a result of the particular fermentation in this barrel rather than anything inherent to the wood/spirit themselves.
Mouthfeel – Similar, feels slightly richer, maybe just drinking it second a bit warmer and flatter.
Drinkability & Notes – It is a fine beer, but next to the Rumble-barrel it is missing that extra something that makes a great dark sour. Academically it is the same, but I’m tossing the last few sips and going back to the other bottle for the last few ounces!