I wanted to share my latest modification to my single-vessel BIAB system. I basically added a second vessel (mash/lauter) that is fed by my electric brew kettle with reverse circulation from the bottom (similar to the Braumeister but with two vessels). The system is controlled by an Arduino using a modified version of Mathos Braudino code. When the pump shuts off gravity allows the wort to back flow through the pump and into the brew kettle. This provides automated mash-in and mash-out with no addtional, pumps, valves or hardware.
No worries about the pump exposing the heating element from slow flow in the conventional circulated BIAB approach.
No need to lift the bag to sparge
Simple: 1 pump, 1 heating element, 1 temp probe
Fully automated mash-in and mash-out
And the best part: I've programmed the Arduino to provide a delayed start. So, I can fill the system with grain and water and set the system to start eain the middle of the night or when I'm at work. When I return it is ready to start the boil. This should cut my brewing time down to about the same as extract and allow me to brew on other than weekends.
The second vessel is a plastic bucket with a false bottom. The false bottom is made from the bottom of another bucket drilled with holes. I've added 3 legs made from stainless carriage bolts to keep the false bottom from jamming too far into the bucket.
I put the false bottom inside
a BAIB bag and put the bag and false bottom in the bucket. The thought behind this is to use the false bottom to seal the sides of the bag against the bucket so that all of the flow has to go through the bag and the grains and not sneek between the bag and the wall of the bucket.
Here is the bucket with grains and the bag:
Here is the mash in with the bag zip tied shut:
Return flow is from copper pipe near the top of the bucket:
I've tried one brew so far and got 65% efficiency. I normally get 70% with the single vessel BAIB. But, I only single crushed the grains. I normally double crush for the BIAB. That will be my next experiment.