Maltzilla malt mill: my rig and a brief review

[corncob]

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.

 

[DuncB]

So from a several year user of the Maltzilla to a new user I'm wondering if it's still all roses with your milling ?
Now that you are a few brews in.

 

[corncob]

Actually, right after the maiden voyage with the new mill, certain circumstances grounded my whole brewing enterprise. Very lame. I was planning to get back and update this thread after 3 or 4 more brews though.

Personally, I'm optimistic about the mill, except for the longevity of the plastic construction and chinese motor. Only time will tell there. The crush is good, but contains some flour. I think that's par for the course without conditioning with any 2-roller or homebrew 3-roller (where the husks must pass through the tighter gap along with the kernels). I love how it doesn't clog. I love the drill battery option. I don't mind the speed a bit, considering I can walk away from it while running. If it doesn't self-destruct after a dozen brews, it gets 5 stars from me.

 

[DuncB]

I've had mine a few years now.
Plastic lasts fine. I use mine with a 18v battery.
I do condition makes a difference.
The gap on the gauge is " nominal " it does not correlate with the markings on the adjuster. Kegland confirmed this when I wrote to them about this.
The main issue you will find at some stage is the non powered roller will stick and the crush stops.
You'll need to free it from the lower side with a finger then it will run again for a while.
About 20 uses in at less than a year I couldn't get it to crush for more than a few seconds.
Extremely frustrating.
Took it apart you'll need a circlip removing pliers and lots of husk and flour in the housing around the bearings.
The bearings have a non perfect seal just a plastic cover and opening this up it was full of flour.
All 4 bearings.
Clean and reassemble.
You will then find reassembly nigh on impossible to get the gap the same as before.
Kegland said they'd never had this problem reported! and why not just change the bearings. My feeling it should be a fully sealed bearing.
I've had to take it apart another three times since then when the problem recurs.
I expect the mill to stick at least once every crush and as the frequency increases I see a teardown looming.
On the positive side I like the crush I get no torn or chopped up husks.
I do vacuum the mill after each use, kegland suggested I blew compressed air through it after each use. Didn't see a compressor as part of my mill requirement.
I have not seen a long term review from portly gentleman, or from Gash on the homebrew channel.
It is possible of course that kegland explored my advice and spent a few more cents on the bearings and you will be fine.
Keep us updated.

 

[corncob]

Thanks for the info. If I get flour migrating into the bearings, I'm going to be extremely disappointed.

 

[DuncB]

Thanks for the info. If I get flour migrating into the bearings, I'm going to be extremely disappointed.

I can pretty much guarantee you will.

 

[simbabrew]

I had mine clog up due to flour in the bearings, but I was using water to clean it. Since replacing the flour-caked bearings and never having water touch it, it has worked flawlessly for a couple years. The bearings were pretty cheap and easy to source on Amazon. I think it depends on how good the bearing seals are.

 

[DuncB]

Did you get the fully sealed bearings with metal covers over the bearings?

They are fit for purpose. Agreed not expensive to replace but the mill is pricey and should come with a decent set of bearings.

 

[simbabrew]

No, I just got some bearings from Amazon that are the usual Chinese quality. They have plastic covers over the bearings. I must of got lucky!

 

[DuncB]

No, I just got some bearings from Amazon that are the usual Chinese quality. They have plastic covers over the bearings. I must of got lucky!

Well done.
The bearing caps do flick off with a jewellers screwdriver or something fine and pointy and can be vacuumed clean if problems do occur.

 

[oakbarn]

I can pretty much guarantee you will.

I just put my Maltzilla togather. The instruction could have been clearer and what gap to set is non existant. They say add some grain an crush and look at it. I would love to have a starting point. Two credit cards? 4 credit cards? Have seached the web and unless I want to buy a Maltzilla there is nothing else.

 

[corncob]

I have settled on the "1mm" setting. You could start there. But I'm going by the look of crushed grain, because that's really what matters.

 

[DuncB]

The readings on the dial for gap are arbitary really.
Adjust the dials to give a gap about 1mm or a bit less, I do condition my grain.

THe instructions are poor. I find my system copes with the fine crush really well I'm not using BIAB.

I can't check gap till I get home but it's not more than a mm I'm sure.

 

[oakbarn]

I have settled on the "1mm" setting. You could start there. But I'm going by the look of crushed grain, because that's really what matters.

@concob:
@DuncB

Thanks. I ordered a Gap Guage that read from .5 to 15 mm. I will try about 1.5 to see how it does.

How do you condition the grain? I think I read to mist and leave 6 hours.

 

[DuncB]

Okay home now.
Measured the gap and it is 0.75 mm tight pushing the feeler gauge through the rollers.
This on my maltzilla corresponds to the 0.25mm reading two settings around anticlockwise from the 0mm reading.
Attached photo trying to show this.
I'd go one notch wider than whatever your 0.75mm reading is to start with and see how your system works with that.

To condition take total weight of grains. Subtract weight of any flaked grains, wheat or roasted grains.

Take the weight and work out 2% of this weight, ie 4kg grains ( after subtractions above) so 2% is 80g.

I put my grains in a rectangular plastic storage bin and then get a spray bottle and fill with water. Weigh the bottle and say it weighs 300g then spray grains ten times or so, mix with my hand and then respray.
Keep doing this until 220g left in the bottle. This way you have sprayed with 2% by weight.
I then put the lid on the storage bin for 20 minutes or so, then at milling time add in the roast grains if you have any and mill them.
Have a look at the grains as you mill them, if you think not fine enough try one notch tighter.

I mill the wheat and things like rye tighter than for barley.

Hope this helps.

 

[corncob]

I have never tired conditioning, actually. I know it works, but I'm lazy and using a bag anyway. Planning to go back to a real mash tun soon though. I'll probably have to start conditioning. My maltzilla leaves halfway decent intact husks, though, so maybe not.

 

[DuncB]

I get nice husks with mine conditioned, just cuts the flour down a little.

 

[oakbarn]

Okay home now.
Measured the gap and it is 0.75 mm tight pushing the feeler gauge through the rollers.
This on my maltzilla corresponds to the 0.25mm reading two settings around anticlockwise from the 0mm reading.
Attached photo trying to show this.
I'd go one notch wider than whatever your 0.75mm reading is to start with and see how your system works with that.

To condition take total weight of grains. Subtract weight of any flaked grains, wheat or roasted grains.

Take the weight and work out 2% of this weight, ie 4kg grains ( after subtractions above) so 2% is 80g.

I put my grains in a rectangular plastic storage bin and then get a spray bottle and fill with water. Weigh the bottle and say it weighs 300g then spray grains ten times or so, mix with my hand and then respray.
Keep doing this until 220g left in the bottle. This way you have sprayed with 2% by weight.
I then put the lid on the storage bin for 20 minutes or so, then at milling time add in the roast grains if you have any and mill them.
Have a look at the grains as you mill them, if you think not fine enough try one notch tighter.

I mill the wheat and things like rye tighter than for barley.

Hope this helps.

No Pix