Brew in a Bag, also known as BIAB
As simple as I can make it
Equipment List
1 Pot , with lid, at least 40 litres in volume (I use a keggle)
2 Bag, swiss voile (mine is 0.5m wide by .75m high)
3 Mash Paddle
4 Heat source
5 Thermometer
6 Insulation (old comforter, blankets, sleeping bag, etc)
The Bag
A lot of talk is generated on this simple thing.
What you are making is a pillow case out of mesh.
In fact a new washed pillow case (poly cotton/polyester) will work quite well, just not as efficient.
Best material so far, Swiss voile (fabric land carries it).
The material comes in 1.5 meter widths so 1/2 m will make a bag.
Use of sewing machine and ten minutes will make a bag, ask your mommy, girl friend, sister, etc
If no sewing machine a needle and thread will do (about ½ to 1 hour)
A draw string closure will be nice, but not necessary.
Also I believe a 1m by 1m square of the material will make a bag, with no sewing. Just push the material into the pot with 4 spring clamps holding up the edges (I have not tried this yet).
The Grains
A fine crush is best for BIAB, I use a 0.5mm (0.02”
gap on my barley crusher mill.
Some flour is fine and expected.
Procedure
for a five gallon batch
1. Add 28 litres (7.5 gallons) of water to the pot.
2. Begin heating
3. When to about 10c less than the mash temp add the bag and the grains
4. Stir the grain with your mash paddle well, no lumps.
5. Keep heating and stirring until your mash temp is reached (65 to 68c)
6. Turn off heat
7. Put lid on pot and insulate
8. Leave alone for 60 to 90 minutes
9. Remove insulation
10. Apply heat and stir until mash out temp reached (~76c)
11. Shut off heat
12. Lift up bag, drain, squeeze, drain, squeeze,drain, repeat as necessary I try to get every drop.
13. Apply heat bring to boil, add hops, cool, pitch yeast, etc
With the above equipment and method I get ~75% efficiency, same as my three vessel system.
There are lots of room for modifications to above method, knock your self out.
However in my opinion keeping it simple is what BIAB is about
“It's dead easy” Uncle Dennis, 40+ year beer maker