Nobody really knows for sure how the first “eisbock” came together but we can assume that it was a pure accident. One version suggests that somebody left a cask of beer outside during a very cold winter night some hundred years ago.
Physics tells us that the explanation is quite simple: It is based on the different freezing points of water and alcohol. While everyone complained about the bitterly cold winter of 2014/2015 it gave us an opening to not only find out how exactly this natural process works but also how it impacts on the flavor and aroma complexity of the brews inside such casks.
We also theorized that its impact on flavor and aroma should be quite different from such versions that use modern freezing technology to create “eisbock style brews.” In order for us to go for the highest possible impact we increased the stakes quite a bit:
1) We did not simply transfer brews into casks but used original Zymatore wooden barrels in which the chosen brews had already started to transform themselves for quite some time. Some were filled in 2013, some in early 2014.
2) We moved 24 of these different Zymatore wooden barrels into our uninsulated “eis-barn” to allow for nature to completely take over the entire process.
3) From mid-December, 2014 through mid-March, 2015 the bitter cold temperatures made their way through the wood into the precious liquids. Our biggest concern was that the expanding ice might burst our precious Zymatore barrels (again, physics tells us that water becomes less dense below 39F and therefore expands when starting to freeze).
4) Around mid-March, 2015 we opened the bungs to find incredibly interesting results: An ice ring had formed inside the wooden barrel, around 3″ to 4″ thick. When we drilled through it we reached the liquid. Using a pipette to draw a small sample we found marvelous brews of most intense flavors and aromas.
5) We then transferred some of our “Eis Zymatore Projects 2014/15” into kegs. To be tapped at some of the upcoming 2015 B.United International/OEC Brewing festivals and out in the market. Many, however, were transferred into new Zymatore wooden barrels (we chose beautiful French Chardonnay wine barrels from the remarkable Matthiasson Vineyard California) for a very rare Double-Zymatore-Aging undertaking.
6) Lastly, we will of course use all Eis Zymatore Barrels (after dumping the frozen ice) for future Zymatore projects. Rumor has it that OEC has already transferred some of their new Lambic style wild brews into some of the former eis-barrels.
UPDATE – Jan. 2016: The first release from the eis-barn is finally ready! Come by OEC Brewing this Saturday, 01/16/2016 from 12-7 p.m. to try the first release on tap and take it home it bottles!
Introducing Imperium. Imperium is part of our Frigus project. Frigus barrels are selected and aged in our small barn. The barn is neither heated nor cooled and in the winter drops well below freezing exposing the beer to the natural fluctuations of our climate. Imperium is a wheat wine that was brewed specifically for this project and aged 1 1/2 years in red wine barrels from South Africa. Available in bottles and on draft. 500ml/$16. Limit 6 bottles per person.
OEC Brewing, 7 Fox Hollow Rd, Unit B, Oxford, CT 06478.