In Perpetuum: Pale Sour Ale

Brewing on cheap equipment in a rented apartment constrains my process in various ways.  For the most part these are constraints I’m happy to work with, but one thing that has started to bother me in some instances is my small batch size.  It doesn’t matter so much in the running beers I make, since the turn around is supposed to be quick; but it can be disheartening to wait a year-plus for a batch of sour beer, only to find that if you let yourself enjoy it freely its almost gone a few months later.  What’s more, it limits the amount of beer I have lying around for other blending projects.  Dedicating 1.5 litres of sour to blend with a batch of saison amounts to reducing my batch size by almost 10%, which in a small batch is a significant loss.

I’ve taken various steps to remedy this.  The biggest has been getting a pipeline of sours going, so that I always have new batches ready to bottle; but even here I find that there’s something frustrating about starting from scratch each time, knowing that it will be a year until you get to drink this beer, and that it will probably be almost all gone in less than half that time.  This is part of what drew me to using small proportions of these older beers to cut younger beers, or to inoculate new batches, as it provides a way of extending each batch further.  Starting some kind of solera-system seemed like a natural extension of this.

Of course the idea of using a solera-style system for brewing beer is not a new one (even among home brewers), but people have started to do some very interesting things with it in recent years.  For instance, Michael Tonsmeire has shared lots of information about the the wine barrel soleras he shares with Nathan Zender.  They have a great set-up, pulling around 20 gallons every year, and then splitting this beer to treat in various different ways: e.g. adding hops, flowers, or fruit.  It provides an endless base for experimentation.

Most versions I’ve read about are done on a scale that would be impossible in my space, since I can’t house a barrel, and brewing 60 gallons of wort 3 gallons at a time would be a Herculean task.  But that doesn’t mean I can’t apply the same ideas on a smaller scale.  Brewing sixty gallons might be impossible, but I can easily do six gallons to fill a large carboy in a double brew day.  In fact, if I had 3 gallons of aged sour lying around, I’d only need a single batch to have something already well under way…

So that’s what I did. The base beer here is an 11 month old version of the Flanders Pale Ale recipe from Wild Brews. It was initially fermented with a new pack of Roeselare blend, and had about 10ml of ECY20 added to it after a few months in primary.  The beer has a lovely gentle brett funk at the moment---lots of hay and light farmyard---but, as is often the case with a first pitch of Roeselare, its still not very sour at all (see photo).   The recipe for the younger beer is slightly different (I’ll put it at the end of the post), and I intend to stick with this one in future. My hope is that there is a healthy array of brett and LAB at large in the aged beer, and that the addition of fresh beer (which finished relatively high at around 1.014) will provide them with what they need to increase the overall acidity.

This week I combined both 3 gallon batches in to a 6 gallon carboy bought specifically for this purpose. I’m planning to run this beer in a proper solera-style system: pulling out three gallons into another carboy in 9-12 months, and topping up the original with 3 gallons of fresh beer; then perhaps even pulling from the 3 gallons to fill smaller jugs 9-12 months after that, and refilling each vessel with beer from the next youngest batch.  Eventually, if I stay put long enough, I’ll have a range of blends at different ages: according to Michael Tonsemeire’s solera spreadsheet, assuming I pull half of each vessel every nine months, the three stages should eventually converge on 0.7, 2.2, and 3.7 years---though I doubt I’ll stay in this apartment long enough to see that happen. 

I’m thinking of this as the base for further beers, rather than something to be drank in its own right---something I might use to cut younger saisons, or add fruit or dry hops to.  For instance, the smaller volumes in the oldest vessel would be perfect for adding acidity too a blended sour or a saison. Based on my experience so far, it only takes about 15% to add noticeable acidity to a clean beer.

In fact, if this system works well, I’m thinking of trying it with other beers too: perhaps doing a double batch of a dark beer in another 6 gallon carboy, and running it in the same way with pulls every 9-12 months, so that I always have a range of light and dark sours on hand for blending.  (Here I’m again inspired by New Belgium’s process with their light and dark beers, Felix and Oscar, which you can read about in American Sour Beers.)

Recipe:

Measured O.G.	1.057
Measured F.G.
ABV.
Mash:	156°F
Malt:
42.9% Pilsner
42.9% 2-Row
10.7% Flaked Wheat
3.6% Flaked Oats
Hops:
EKG	60 min	21.4 IBUs	(25g@ 4.29%)
Yeast:
WY3522