I've made a couple of 'fast' brew-to-glass in one week beers.
I've had luck with lower gravity beers:
1.045 OG Pale Ale, dry hopped in keg in steel tea ball.
1.036 OG Belgian Single (Pilsner LME and Saaz hops, super simple)
1.042 OG Belgian Wit
Yeast and pitching:
Make a starter morning of brew day, put it on the stir plate. Get the yeast active for pitching. Pitch the whole starter. Pitch the at least the correct amount (or a little more) of yeast and aerate. I also use the white labs yeast nutrient servomycies.
Assuming the target fermentation temp is 65F. , cooler first day as 63-64F, and then let(force) it rise day 2 and 3 to 65-66F. Raise 2 degrees above desired temp day 4 and 5 to 67-68F.
Transfer onto finings into keg and cold crash on day 6. Put on 40 lbs of CO2 pressure to carbonate. I'll put a half full 6.5 gallon bucket of water in my kegerator on day 4 and place the keg in the bucket when cold crashing. Yes it may 'shock' the yeast, but this is a fast beer. It gets the beer cold fast, and gives a couple extra hours for the finings to work. I use Biofine Clear (works faster than gelatin for me) to flock the yeast out faster in the keg.
Day 7, move the beer to a serving keg. I put the first 1/2 gallon (cloudy) in a growler and place it in the fridge to consume later. Like if there's a over drunk jerk that demands a beer.
Or to enjoy a couple days later when it has settled.
Has anyone tried to make a low gravity coffee/breakfast stout in a week?