This is a document of my Solera project, otherwise known as the “Morph” range of beers.
Solera is a process for aging liquids such as wine, beer, vinegar, and brandy, by fractional blending in such a way that the finished product is a mixture of ages, with the average age gradually increasing as the process continues over many years. In wine, this is a way to achieve a complex blend of vintages that is consistent over time. In modern craft beer brewing it is often a way to maintain a culture of wild yeast and bacteria.
For me this will be a way of creating a range of complex beers that are aged on oak with Brettanomyces and Bacteria. Periodically, 2/3rds of the batch is to removed and replaced with a different beer. The aim is an ever changing beer with wood aged and sour notes, each batch containing characteristics of the beers that went before it.
Commercially, wood aging is done in large, usually oak, Hogsheads or Foedres. Large wooden vessels that impart their own character to the beer whilst habouring all the living organisms required for souring and Brett fermentation. Unfortunately, research has shown that, whilst available 10-20L Oak barrels aren’t really suitable, as wood is permeable to oxygen, their small size results in too much oxygen pickup due to the low volume to surface area ratio. Too much oxygen can promote the growth of Acetobacter, that will happily turn beer into vinegar, given the opportunity. The simple solution was to use a non-permeable vessel, a Stainless Steel Corny keg. I opted to use my 9L keg for this project. Allowing me to draw off enough for 18x330ml bottles, and refill with 6L of wort, partially fermented wort or beer from another brew.
The obvious alternative to putting beer into an oak barrel, is to put oak into beer. However, barrels are more than just oak. During the construction of the barrel, oak planks are heated in order to curve the staves for the barrel. During this heating process, the Cooper can control the “toast” levels of the barrel to typically either light, medium, or dark. Barrels are sometimes charred for some applications such as aging Bourbon. This toast or charring will then impart different flavours into the beer it contacts. To replicate this I bought some untreated oak chunks (sold for Smoking/BBQing) and toasted or charred them.
Charring was done in a hot dry pan on one side of the wood chunk to replicate the internal charring on a barrel.
Toasting was done as outlined in this great post, Toasting Your Own Wood at three different temperatures in the oven. One hour at 230, 320 and 420F, to give Oaky, Sweet and Toasty/Vanilla flavours, respectively.
Next up…….The bugs and beer.