Before my 11-year homebrewing sabbatical, I was using a 3-vessel setup and getting all my grain pre-milled from a supplier that had a consistent coarse crush. Since I started back, I have been using a BIAB setup and crushing with a corona mill turned by a battery drill. I just upgraded to a maltzilla. Event though the reviews out there are mixed, I like the spirit of the design, even if the execution might be weak in some places (I design machines for a living). My rig:
I spared no expense and went straight to junk pile for materials and vowed to use no measuring tools in its construction, being off the clock. The motor is rated for 24V, but I am powering with a DeWalt battery at only 20V for convenience--therefore it will turn slower and make less torque when loaded up. The drill battery adapter from Amazon is about the coolest thing I have been lately--it works as expected and includes an automotive-type fuse and switch. One thing to note is the baffle I put in the hopper. It keeps the weight of grain on the rollers to a minimum and also limits the speed at which grain flows into the gap. I believe this is the key to success with this mill. It takes a few minutes to go through a batch of malt, but it does not clog, hangup, or stop--even running at 20 volts. This is ideal for me, because I want to be doing something else while the mill runs.
Here is a picture of the crush for the maiden voyage brew:
This is UNconditioned malt run on the 1.25mm setting--I am sure the gap size is very "nominal," considering the stack up of parts that produce it, but it should be pretty repeatable if the flow rate of grain is fairly consistent. I got very little flour and very few uncrushed kernels. There are quite a few kernels that appear intact, but only because the husk is still holding the broken pieces of the kernel together. I think I will tighten this up a notch or two going forward, just to account for variation in kernel size, but I wanted to explore the bounding case. The first beer is a mild (boiling now). Obliterating the malt with the old corona mill gives me 82% mash efficiency for this recipe. That is with a 45-minute-total mash. Today I mashed for 75 minutes (60@158F + 15@162F) to be sure that any reduced efficiency was due to the crush, not due to incomplete extraction. I got 70% efficiency. This is a 1.035 OG beer. It is too early to tell for sure, but I believe (based on prior experience and this first mash) this number will hold for bigger recipes up to some threshold where the total volume of water used comes into play--probably around 1.045.
Would recommend at his point, but I may come back and add to this if my opinion changes in the future.
Edited to add: the bag squeezing was very, very much easier and less productive this morning, without all that flour.
I spared no expense and went straight to junk pile for materials and vowed to use no measuring tools in its construction, being off the clock. The motor is rated for 24V, but I am powering with a DeWalt battery at only 20V for convenience--therefore it will turn slower and make less torque when loaded up. The drill battery adapter from Amazon is about the coolest thing I have been lately--it works as expected and includes an automotive-type fuse and switch. One thing to note is the baffle I put in the hopper. It keeps the weight of grain on the rollers to a minimum and also limits the speed at which grain flows into the gap. I believe this is the key to success with this mill. It takes a few minutes to go through a batch of malt, but it does not clog, hangup, or stop--even running at 20 volts. This is ideal for me, because I want to be doing something else while the mill runs.
Here is a picture of the crush for the maiden voyage brew:
This is UNconditioned malt run on the 1.25mm setting--I am sure the gap size is very "nominal," considering the stack up of parts that produce it, but it should be pretty repeatable if the flow rate of grain is fairly consistent. I got very little flour and very few uncrushed kernels. There are quite a few kernels that appear intact, but only because the husk is still holding the broken pieces of the kernel together. I think I will tighten this up a notch or two going forward, just to account for variation in kernel size, but I wanted to explore the bounding case. The first beer is a mild (boiling now). Obliterating the malt with the old corona mill gives me 82% mash efficiency for this recipe. That is with a 45-minute-total mash. Today I mashed for 75 minutes (60@158F + 15@162F) to be sure that any reduced efficiency was due to the crush, not due to incomplete extraction. I got 70% efficiency. This is a 1.035 OG beer. It is too early to tell for sure, but I believe (based on prior experience and this first mash) this number will hold for bigger recipes up to some threshold where the total volume of water used comes into play--probably around 1.045.
Would recommend at his point, but I may come back and add to this if my opinion changes in the future.
Edited to add: the bag squeezing was very, very much easier and less productive this morning, without all that flour.
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