Lambic fermentations are complex business. While a commercial cocktail of a half dozen microbe species can replicate the major flavors (e.g., lactic and acetic acid, ethyl lactate, ethyl acetate, 4-EG, 4-EP) it is impossible for them to replicate every one of the hundreds of compounds produced by the dozens of species responsible for each lambic brewer or blender’s house flavor. Think imitation vanilla compared to real vanilla beans. Thank goodness each bottle of gueuze comes with a free sample of microbes!
However, the microbes in the bottle do not necessarily represent all those responsible for each stage of the fermentation. While many of the oxidative yeast and Enterobacteriaceae at work early in the fermentation have been dead for years (thankfully - considering some are pathogenic) the acids, alcohols, and enzymes they produced have a profound influence on the aromatics produced by the hardier microbes which follow.
To get the best of both, I naturally cooled my sixth batch of lambic uncovered in my barrel room and then pitched a starter grown from six especially delicious bottles of 3 Fonteinen gueuze. Always judge what to pitch based on the beer in the bottle, rather than the label on the bottle (although fresher is always better). If I was gutsier, I would have allowed my local microflora a 48-72 hour head start before pitching the starter. Maybe next time!
I've been storing these bottles on their sides, so an appropriate excuse to breakout a lambic basket!
Smell – Potent mix of dusty-Brett funk and brighter lemony-tropical-fruitiness. Has some mineral-like notes as well. It is reminiscent of 3 Fonteinen Oude Gueuze more than anything else; more towards my preference for citrus zest and minerals rather than strong horse stall or vinegar.
Taste – Sour, but not bracing. Drenched in citrus (lemon rind) which gives it a bright/lively character. Ripe pineapple as well. Nicely funky, fresh hay, and old baseball mitt. Each sip finishes minerally, a little chalky. Just a hair of acetic sharpness in the finish, less than many commercial gueuzes. It retains an edge of sulfurousness that this batch was saturated with when it was young (thanks to some time with a hard stopper).
Mouthfeel – Refreshing, crisp, although it could use slightly more carbonation to reach classic gueuze-level pop. Light tannic astringency.
Drinkability & Notes – Over the last eight years, my lambic/gueuze-style beers have slowly, but surely improved, and this is no exception. It is by no means at the level of my favorite three or four Belgian lambic producers (when they’re on), but I’d give it ~85-90%. Not bad for an unblended lambic that was aged in a plastic carboy! Turns out a turbid mash may not be worth the added effort when you have the right microbes!