I did my second and third ever biab 20L stovetop batches over the weekend.
I'm having a bit of trouble with efficiency (i think?).
4kg grains, after topping up to 18 or 19L only getting around 1.040. Never higher.
Mash @ around 64/65 *C for 90 minutes. Usually only losing 1 maybe 2 degrees over that time.
For sparging I heat around 4L of 70*c in a seperate pot, then after the mash I put the grain bag into a big bucket, open it up and poor the 4L of water over the grains. Then I dunk it in like a teapag a dozen or so time. Then tie it to the door handle and wait for 10 mins whilst it drips. Then i squeeze the juices from it as best i can and add the contents in the bucket back to the 19L boil.
After 1hr boiling usually left with around 11L in the pot. Topping up another 7 or 8L gives my 1.040.
Does this sound about right? Final ABV should be roughly 4% if FG is around 1.010.
My ex-FWK containers are now my fermenters. ie. 15-15.5L batch size. I use 3.1 kgs base malt and 200-400g specialty grains. Similar to your process description, I use two Big W pots. The second for a dunk sparge. ie. 14L strike water, cover & mash for 90min minimum. second pot has 8L heated to 78c and when the bag & grains are inserted into this pot I give the grains a steady stir for a few minutes. I also always perform a mash-out to 78c, stirring continually. My OG is consistently 1050-1054
http://www.aussiehomebrewer.com/forum/inde...mp;#entry921224
Cheers
What's the next step up from the stovetop? Suppose buying a 30L Urn to do full volume mash?