Here is a summation of a few years work. I've compared about 15 different decoction schema over 10 different grists. For each of these decoction experiments I also ran controls using a single infusion at 149F and a multistep infusion at 128F, 144F and 152F. Thats a total of 170 independent experiments.
All used the same yeast with the same yeast numbers (2mill/ml/deg P). No starters were used as thats another sticking point so I used the dry 34/70 yeast having bloomed it or 15min prior. All were oxygenated to the same level using a dissolved oxygen meter. All fermented at the same temperatures 49F and lagered for the same ratio (1 week/ deg plato) at the same temperatures 32F. This is the only way to ensure that the only thing changing is either the schema or the grist.
Each experiment was randomly assigned a number and tasted double blind. Each group of beers were tasted as a family of grists rather than the type of decoction. Additionally, three bottles of each were kept at lager temp (0C), room temp (13C) and conditioning room (25C) to gauge the shelf life and stability.
Here are the results:
On a whole the decocted beers were/had:
- darker by about 1-2 EBC but varied greatly on schema
- higher efficiency (from 5-12%)
- much more clear
- more grainy and less husky
- much longer shelflife and stability over both
- more satiating - not necessarily more body but more velvety
- most had that extra 'thing' that made them stand out...call it complexity or whatever
- took more time and energy to make
