My favorite thing about brewing sour beers is that there are so many ways to go about the process and still end up with excellent beer. The biggest key for me in making great sour beer is blending, and that means you have to have a decent selection of different beers from which to choose.
You have to play around with everything, from recipe/grain bill, to microbe choice, to time you pitch the microbes that you select, to what format and how long you age the beer. I brew on a Blichmann electric system and will make about a dozen different mixed-fermentation beers throughout a given year. Usually that means splitting a single large batch into separate carboys with different microbe blends.
My favorite microbe blends come from smaller specialty labs, such as The Yeast Bay and East Coast Yeast. Again, there’s no one single “right way” to do it, but I usually pick a culture the lab has already blended and pitch it all up front at the same time. Then that carboy will sit on the floor of my basement and usually won’t get touched or sampled at all for six to nine months. That’s what I have found to be the best mix of results and practicality for me.
Once per year, I’ll also make a 15-gallon (57-liter) batch using a traditional turbid mash, inspired by the process that Cantillon uses. That recipe departs from tradition after the long boil, however. After knockout, I chill the wort straight to pitching temperature, rack to a neutral oak barrel, and pitch a few vials of whatever mixed culture I feel like that year. I don’t aerate the wort because oxygenation initially favors bacterial growth over yeast. Yeast tend to be a little hardier than bacteria, so it just allows them to get a little head start. That’s my standard practice for all of the sour-beer worts that I make.
My simpler, infusion-mashed beers make up the majority of my blending stock. I love the results I get from the turbid-mashed beers, but it’s unsustainable for me to do all that work every time. When doing the infusion beers, I like to try to imitate the starch/dextrin/sugar makeup of a turbid mash. So I like to add some adjuncts, such as oats or some type of less fermentable sugar source, to keep the Brettanomyces and Pediococcus active through the long aging process. For that, I like to build in some extract and/or maltodextrin powder.
Once a year, I sit down and do a tasting of every fermentation I have going. I pull a decent-sized sample, flush with CO2, then reseal. Then I take some time with each beer and take plenty of notes. It helps to invite over friends who have varying “skill” at tasting. We evaluate each beer and determine its pros and cons. There’s no shame in saving a batch for next year or even dumping the whole thing.
Once I have my notes, I start thinking about where I want to go with different blends. Usually I start with a large amount of a particularly interesting batch, then slowly add small fractions of other beers that add missing components or that enhance and support something interesting. Pipettes and graduated cylinders help.
Then, I scale up the selected blends into a corny keg, mix in the amount of priming sugar I want, and add a measured amount of fresh yeast. Straightaway, I use a beer gun to fill heavy glass bottles. I keep them warm for carbonation and keep them around a little longer for conditioning. I think “bottle shock” is a real thing in sour beers, and if the dreaded “Cheerio” flavors of tetrahydropyridine (THP) are present, those will also fade with time.
Photo: Matt Graves/mgravesphoto.com