I think my brew day is a touch over 4 hours for a double batch from dough in to cubing (excluding grain prep and auto HLT). Obviously chilling would add to this... but never done it, so don't know by how much.
I find i the time to be saved is in the sparging and lautering phase. Here's what i do which takes about 30-40 mins from end of mash to first hop addition (it's much quicker doing single batches... probably save another 10mins);
- I don't do a Mashout. I vorlauf then drain the mash tun at the end 60min mash (as Ross says you can save time if you know conversion has occured.. read here about
iodine test)
- Rambo burner now on full to bring first runnings into kettle
- Batch sparge round 1 with near boiling water, to bring the grain bed up to 76C. Wait 10min. Vorlauf and drain tun as fast as possible. (i have a 2mm perf false bottom).
- By the time the first sparge is in the kettle the wort is pretty close to boiling and have to dial back the burner
- Batch sparge round 2, to keep grain bed at 76C, wait 10, Voraluf and drain tun as fast as possible.
- By the time batch sparge round 2 is complete... it's only another 5mins before i have 50+ litres at the boil.
Another place to save some time is when draining the kettle. I now have a hop stopper on the kettle, which stops all hop debris and most hot break from exiting the kettle. Therefore i don't need to whirlpool before draining (i do, to ease the load on the blocker, but probably don't need to). So get a decent hop blocker and perhaps use hop flowers as a break filter and you could drain the kettle almost immediately after flameout... saving yet another 20-30 mins.
I'm pretty confident with the above, as a single batch, i could turn out a 3.5 - 4 hour batch into a cube.