Monday, May 6, 2013

Second Pull - Wine Barrel Solera

Our jammed together system. Not too pretty, but 25 gallons in 6 hours isn't too bad!More than three years after initially filling the red wine barrel in my basement with a pale lambic-ish wort and inoculating with a pre-East Coast Yeast test culture of Al Buck’s Bugfarm, Nathan and I are finally preparing for our first true solera pull!

In September 2011 we pulled the first 20 gallons from the barrel, but that was solely the unblended initial fill. After refilling the barrel and allowing it to age until now, the blend is comprised of approximately 60% of the initial beer (3.25 years old) and 40% of the first refill (1.7 years old). The result is a sour beer with an average age just over 2.5 years (for more on calculating a solera's age, download my recently updated solera spreadsheet). Judging both by that advanced age and the flavor of the sample we pulled Saturday, this should be a delicious pull!

T58 was rocking after a few hours, the rest not until the following morning.When we refilled the barrel with unfermented wort last time, it took almost a week to see the first signs of active fermentation. There isn’t much chance for anything really unpleasant to happen when wort is mixed with double its own volume of already soured/alcoholic beer, but it still didn’t seem ideal. For this refill we decided to ferment the beer before racking into the barrel. We used every available fermentor, including my two 20L American oak barrels, to ferment the wort. The five fermentations are currently raging with a variety of dried yeasts: T-58, S-33, Belle Saison, and US-05. I’m especially interested to taste the Belle Saison.

Several people have asked if we are concerned about autolysis (i.e., off-flavors resulting from yeast death). My answer is, “Not yet.” Gueuze producers sometimes age lambic in the primary barrel for up to four years. I doubt they would ever have autolysis problems because after that long there wouldn’t be any Saccharomyces left alive (oxidation is another story). The concern with a solera is that as the trub continues to build with each successive fill it could eventually cause issues, as Cambridge Brewing Company discovered with their Cerise Cassée project. It may also be that as beerstone builds up reducing the wood's porosity the Brettanomyces is no longer able to clean up the compounds released by the primary yeast. Moving to primary fermentation outside of the barrel should also help, assuming we provide enough time for most of the yeast to drop out of suspension before racking into the barrel. We'll siphon out some of the trub during pulls too.

I’ll have another post in a couple weeks to recap how we treat the beer we remove from the barrel. Nathan and I had great luck with our four variations on the first pull (plain, Hallertau, elderflower, and Cabernet sauvignon), but we probably won’t repeat any of those this time.

Our other solera (that lives in an apple brandy barrel) is ready for its second pull as well. It is just barely holding on, pushing the upper level of my tolerance for acetic acid. Luckily topping off the barrel and getting an air conditioner to hold the ambient temperature in the 60s F prevented it from becoming undrinkable since the first pull.

With the coming decommissioning of the group barrels at Nathan’s house and our respective jobs in the professional ranks coming, we’re hoping to keep these two soleras going, but we’ll see.


Brooke said...

Hey Mike, is there any logic to using a pH meter to test acidity? You mention your threshold for acetic acid - are there other acids in sour beer?

Steve said...

Finally started brewing sours after reading your blog for a long time.

Is there any reason that a solera wouldn't work in a 10 gallon barrel?

I don't have room for a larger barrel and could pull 2.5 gallons or less from a smaller barrel.

The Mad Fermentationist (Mike) said...

A pH meter can be valuable, but it isn't the only word in evaluating acidity. Acetic acid is a relatively minor component of the acid profile for most sour beers (Flemish reds are the exception), lactic acid is the more prevalent acid. Acetic acid has a sharper flavor, while lactic is more mellow, even at the same pH. It is very similar to IBUs, the impression of bitterness can vary by hop variety/processing even if the calculated IBUs are the same.

In either case I think training your palate is more important than using analytic equipment. Tasting a beer and having a pH reading could certainly help to focus your senses, but it isn't necessary. The impression of acidity is also altered by residual sweetness, carbonation, temperature etc. as well.

Smaller barrels have substantially higher surface-to-volume ratios than large ones. As a result you'd get more oak character, faster evaporation, and more oxygen exposure. In short, they aren't ideally suited for really long term aging (like a solera). You could certainly give it a shot, but you might need to empty it completely if those other characters (oak or oxidation) advances more rapidly than you can replace beer. With a sour you still need to wait for the gravity to stabilize, so you might be in a position where the beer needs to be pulled, but it isn't ready to bottle. Even on the third fill, my two 5 gallon barrels had enough oak character after just 4 months.

Gene said...

Long time lurker, first time poster (thanks for the many informative, insightful, thorough, and entertaining posts).

I have some small barrels (2 and 5 gallon) in which I've aged beers, up to 9 months. I'm a party to the theory that a person’s sensitivity to oakiness, and peatiness, can be quite different from person to person.

I'm really interested in starting a Solera project (and your comment responses above have been helpful already). I've been pleased with my results on the small barrels and have followed the protocol of having spare beer in small carboys to keep the barrel topped off, to minimize oxidation. It seemed like a chore, and it was. But I imagine it is a problem that is much more critical for small barrels. If you fortunate enough to be able to use (and fill) a full size barrel, there is less exposure due to the shear mass of liquid. I have and old ale recipe I'm partial to and would like to start a Solera project in an 8-gallon barrel, available from a local winery. I'm fortunate enough to have a sub-basement, cut out of bedrock, to store the barrel also. Might you offer your thoughts on long term maintenance/care of barrel of beer? Any thoughts on the process of topping off to keep the headspace to minimum? Better solutions?

The Mad Fermentationist (Mike) said...

I think the best advice is let your palate be your guide. If the beer tastes like it is getting too much oxygen, occasionally topping-off is probably a good idea. You are correct that larger barrels tend to have less issues with over-oaking and evaporation because of their lower surface to volume ratio, but we've been topping off these barrels about once between pulls. Part of that is I use an A/C unit to keep the temperature down in the summer, but that also lowers the humidity and draws more liquid out of the barrels.