I love this topic and hope to see it continue, because it’s something I struggle with. That is, pitting the proportions of base to specialty in my grain bill against mash temp against yeast personality, all in trying to predict my beer’s final body, alcohol and flavor.
Recipe design for me typically starts with a targeted style, followed by yeast selection, and then hours of fidgeting with my grain bill proportions, finally, hopefully, all balanced by mash temp.
As an example… Last week I brewed an oatmeal stout using Wyeast’s London Ale III strain. Expected attenuation = 71-75%.
I looked at Jamil’s recipe for guidance, and saw he uses 73% base malt. Feeling the need to call this beer ‘my own’, as I often do, I decided I wanted to push his recipe into a fuller, less-attenuable territory and this is what I came up with:
70% base English 2-row
11% flaked grains (1 lb of oats, 4 oz of barley)
11% mid-range crystals
8% chocolate/roasted
Mashed smack dab @ 153.
OG = 1.052
Assuming a proper amount of healthy yeast @ 70 degrees, what kind of attenuation do you all think (based on similar experience preferably) that I should be expecting? I know my proportion of specialty to base grain is on the high side, but is it SO high that I ought to expect the yeast to attenuate well below Wyeast’s predicted range? I’m sure Jamil’s recipe is great, but I’m also sure that 73% base malt is not some magical number mysteriously etched into the fabric of the cosmos opening the only doorway to total perfection. Clearly there are other ways to make great Oatmeal Stout. My struggle is, once you have your guideline, just how much tweaking is TOO much?
Of course the one true answer is just to keep brewing, taking notes and ultimately figuring out what works on my own. Yes I know. But what would be the point of homebrew chat forums then?