Sunday, February 23, 2014

Solera: Perpetuum


Two years ago a couple of my friends and I raised money on kick starter to brew beer, buy barrels, and age sour beer. Last summer we had two release parties and had a great experience sharing our creations with fellow beer enthusiasts. Although the group that was responsible for the project have all moved on, some of that beer is still left in the form of a Solera. For the first time I will be pulling from the Solera and adding back fresh wort. Before I get to that let me tell you a little bit about what a Solera is and how this particular one came about.

From Wikipedia:

"In the solera process, a succession of containers are filled with the product over a series of equal aging intervals (usually a year). One container is filled for each interval. At the end of the interval after the last container is filled, the oldest container in thesolera is tapped for part of its content, which is bottled. Then that container is refilled from the next oldest container, and that one in succession from the second-oldest, down to the youngest container, which is refilled with new product. This procedure is repeated at the end of each aging interval. The transferred product mixes with the older product in the next barrel.

No container is ever drained, so some of the earlier product always remains in each container. This remnant diminishes to a tiny level, but there can be significant traces of product much older than the average, depending on the transfer fraction. In theory traces of the very first product placed in the solera may be present even after 50 or 100 cycles."

As you can see the concept is pretty basic, you take a portion of the old beer out and make up the difference with new beer. In this case I only have a single barrel that is being aged. The barrel came about when the Wild Brewing team was bottling 90 gallons of beer. We came down to the last 5 gallons in the first two barrels and decided to put them into carboys so that they would settle out (the yeast cake was kicked up in trying to get out all the beer). When we came to the final barrel we found out we did not have enough bottles and had to leave 15 gallons of beer in the barrel. I was uncomfortable leaving the barrel half empty and so we topped it off with the 5 gallons from the other two barrels and 5 gallons of fresh beer. That brought the barrel back up to 30 gallons with a mixture of 15 gallons of Cherry Saison, 5 gallons of Flanders Red, 5 gallons of a Pale Sour, and 5 gallons of something resembling an all Brett Wit. Since that time the barrel has been topped up with extra wort from several batches of beer, mostly sour or all Brett beers. At this point it has an impressive amount of microflora both from batches of beer, the original inoculum, and several sets of bottle dregs. Here is a list of just the microbes added through beer additions.

  1. Yeast
    • French Saison (3711), Chimay, Farmhouse (3726), Saison (3724), Cherry Yeast, Scottish Ale Yeast 
  2. Brett
    • Drei, Crooked Stave (CMY-001), B. clausenii, B. bruxellensis, B. lambicus
  3. Bacteria
    • L. brevis, L. delbrueckii, Pediococcus
A couple of weekends ago I decided it may be best to move the beer into a new barrel that did not have cherry pits and a bunch of autolysing yeast in the bottom. I used a barrel that had been cleaned and moved all of the original Solera beer into the clean barrel along with 5 gallons of new beer (a highly hopped Scottish ale). This should give the bugs something to survive on and get the beer off any dying yeast.

I tasted the solera beer at the time I was moving it and it was very tasty! A nice round sourness and a whole lot of fruit in the nose. It was a light red color which I hope to darken up by adding darker beers in the future. In about 6 months I will take out 5 gallons and bottle it and freshen the barrel with new beer.