How's your build coming along? Aren't you trying to build a similar unit?
Very good... Yes I am ...sorta.
I was actually building a system to emulate BIAB* (brew in a "bucket") when I first became aware of the BM. It's rather uncanny how similar my "FrankenMeister" is to the BM.
Basically I've got a 15 gal boil pot which will be the basis for the system. I have an older 8 gal pot which will serve the function of the grain pipe. It retains it's bottom and sets about 1 1/2 off the floor of the boil pot.
I have made two sieve plates. One fits tightly in the bottom of the 8 gal pot (mash pot) about 2 " from the pot's bottom. The other sieve plate fits about 2" below the rim of this mash pot.
Circulation leverages a March pump. I pull water from the boil pot via the existing drain valve. This gets pumped to a 1/2 copper manifold which is actually mounted to the outside of the mash pot. The delivery enters the mash pot below the lower sieve plate. Flow at this point is the same as a BM. The overflow from the mash pot drops back into the boil pot and is continuously recirculated.
One difference I have is the solid bottom mash pot. To drain the mash pot when raised, I have incorporated a small 3/8" hole in the bottom of the pot. This should restrict the flow to promote grain bed optimal settling similar to standard vorlauf/fly sparging practices. This hole is sealed by a simple flap valve when the pot is setting on the bottom of the boil pot. This valve opens as the pot is lifted for draining.
Heat is provided by a gas fired system. This system uses a large banjo burner which has been the basis of my boil pot during prior use. I have modified the gas delivery to permit temp control via a PID controller and valve. This system now includes a pilot light to facilitate the on/off of the main gas flow. My initial thermocouple is mounted to sense the output flow temp immediately after the pump.
I may eventually convert to electrical heating if this thing proves useful. I'm basically utilizing my existing system by adding some features to things I already have. I had no idea where this was going until a came across the BM. That was exciting for me since it appears to justify my game plan.
This thread has been an excellent source of info and everyone's participation greatly appreciated.
Construction is almost complete. I'll probably start playing with the circulation and heat control this weekend. I'm probably a couple of weeks from brewing pending start up surprises... there are always some.
The reason I was questioning the capacities of the BM was to get some understanding of the volumes internal to the BM 20L system. In looking at my system I will have significantly more volume capability than what I perceive the 20L BM has. This does make for a tricky design decision regarding the max capacity of my mash pot. I will most likely be cutting a couple of large overflow ports in the side of the pot to limit this capacity. This will be necessary because the system may hold too much water for a 5-6gal grain bill if not limited. I'll have to play with the mash pot volume to determine what's best for this system.
That's it for the moment... Cheers...
