Monday, March 18, 2013

Wild Yeast Culture Experiments - Dregs in Kegs

I have quite a few sour beers in kegs. In fact, this is where most of my 'wild' projects end up. Some of my sour beers are also born in the keg, as I'm often inoculating an unexciting base beer with a mixed culture or transferring it to a keg with mixed dregs. Today I preformed the former, transferring a keg of Double Chocolate Brown to a keg holding the dregs of last year's Sour/Funky Tripel, a beer that placed third at the Indiana Brewers Cup as a Belgian Specialty Ale. Aside from freeing up a keg for an Imperial Stout that will soon be ready, I wanted to add some depth to this Double Brown. I enjoyed having it on tap but thought it was a bit one-dimensional, probably because I let the beer set on cocoa nibs for three weeks! I hope the complexities this bunch of wild yeast produce will create a few more dimensions for this beer.

If given the choice, I would much rather age my sour/funky beers, imperial beers, and lagers in a keg than a glass carboy or Better Bottle. Keg conditioning has several advantages:

It frees up both fermentor and floor space. I am able to stash my slender kegs in a corner of the basement or in my kegerator for cold-conditioning. I can stash about six kegs in the same space  as two 5-gallon carboys.

Oxygen pickup is minimized or eliminated. Sampling, bottling, splitting batches, and adding fruit/spices/oak/etc. are all common procedures that can introduce oxygen. The ability to purge the headspace and transfer under pressure is a substantial advantage.

Bottling is not required and is much easier if you choose to do so. You can either carbonate naturally or with CO2 pressure. If you choose natural carbonation (which I prefer for sour beers), the priming sugar can be evenly dispersed by adding it to the keg, capping and purging the headspace, and then shaking to combine. Bottling from a keg gives the option to bottle a small portion of the batch (a few bottles to take to a party or enter a competition). In addition to the reduction of oxygen pickup, bottling day is also made easier with a counter-pressure filler or Blichmann Beer Gun.

Experimentation with oak, spices, and hops is much easier to conduct in kegs. The ingredient can be added in a muslin bag for retrieval. Many attach a string and run it through the lid, but I've can't get it to seal this way. I've resorted to using fishing line and an unused bobber, which actually works well! In the case of oak, the chips or cubes can be retrieved from the keg and used to inoculate another batch.

Keeping beers in kegs allows them to be ready for blending at any time. Pulling samples for any size tasting panel is a breeze, and the proportions transferred into the blend keg can easily be monitored using a scale or a level strip.

Kegs are sturdy. Any time I can reduce the risk of dropping and spilling five gallons of well-aged homebrew, along with potential injury, I jump on it!

Sour beer on tap is a beautiful thing.

In my opinion, keeping your sour and funky beers in kegs is the easiest way to separate your wild brews from your clean ones, minimizing exposed soft parts and keeping mixed fermentations contained within stainless vessels. I have, for the most part, managed to keep a repository of sour-only kegs, but I have reconditioned sour kegs for clean service without issue, replacing the o-rings and poppet valves. I imagine I will soon need to keg more sour homebrew as my experiments are ready, so I will keep a log of my kegs to trace any sour/funky crossover. Kegs and their permanent components are stainless, so with good sanitation and regular maintenance I feel confident I can keep my clean beers clean and my funky beers funky (in a good way).

Here is a few items to get you started:

Suggested equipment (in addition to a basic kegging setup):
  • Extra sets of poppets and o-rings
  • Out-to-Out transfer line (shown in above picture), to transfer beer from a clean keg to a sour keg.
  • Bottle filler
Cool to have, but not necessary:
  • Additional kegs for sour beer only.
  • pH meter for measuring finished beer pH
  • Level strips or scale for measuring transfer volume
  • Stencil to mark and identify sour/funky kegs. Insignia may include simple text ("sour", "wild", "funky", "brett only", "no pedio", etc.) or a simple graphic (Jolly Roger, pitch fork, effigy of George Clinton).

What kind of homebrewed treasures do you have tucked away in a forgotten Cornie?

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