I have done a few AG brews aiming to produce 5L of wort for fermenting. Recipes use about 3.5L of water for mashing in 1-1.4kg of grain at 68 degrees.
I found that batch sparging works well enough for small batches I top up the mash with 1L. If you wish to 'mash out' then add 1L of boiling water -it might cause issues with tannin extraction so you can just add 70-80 degree water instead. Leave to rest for 15 mins and then lift the bag clear to drain. I do a second batch sparge with another 4L of 77 degree water, resting for 5 mins with a gentle stir at the start. I filter the wort through a hop filter bag before adding it to my pan, usually end up with about 6L into my pan pre boil which reduces to around 4.5-5L after a 60 min boil.
Efficiency of my setup is about 65-70% but it is simple and easy to replicate batches.
Typical brewday is
Boil 8L of water, simmer for 15min and leave to cool to 72 degrees approx 1 hr
Dough in with 3.5L, leave to mash for 1 hr
Top up with 1L boiling water, mix and rest for 15 mins
Filter to boil kettle via hop bag 5 mins
Second batch sparge 4L of 77 degree water, gentle stir and rest 5 mins
Filter to boil kettle via hop bag 5 mins
Boil for 60 mins add bittering hops
Add aroma hops/flavours as per recipe
Add fining's last 15
Cool to 24 degrees and transfer to FV 5-120mins depending on cooling method
check temp is below 20 and pitch yeast
Mix yeast by shaking up FV to aerate wort 1min
Total 3 1/2 - 5 1/2 hours.
Boiling water and cooling it takes the longest. If you can sterilise water in advance and then just reheat the individual volumes to the temperatures required it is quicker. Cooling is much faster with a chiller but just standing it in a water/ice bath will cool it in about an hour. No chill works well if you are in no rush to pitch your yeast. I have done a step mash too by starting with a thicker initial mash and mixing hotter water with good results.
