Milling Problems

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Hi All,

I've been reading the board here for a month or so, finally decided to get off my bum and write something.

I've been doing AG for a couple months now, maybe 6-8 batches so far. results have been really tasty, but i've been having lots of efficiency problems, it's been something like 65%, sometime down to 55%. prety frustrating. the best i've got has been low 70's.

anyway, i think my milling has a lot to do with it. i bought a marga molino maybe 2 months back, which has been good - i've modified it with a baseboard & drill stand & larger hopper. i've been running it using a 12v battery drill, which has worked ok, but it seems to take forever to grind the stuff. recently i've found some posts here quoting grinding 10kg in 15min or 5kg in 5min with a marga, i've been doing more like 4kg in 1hr, at a coarser setting than i'd like. i saw this morning some advice to slow the drill speed, which i tried (on the notch past 2), but if anything it made the feed slower (although the grind seemed quite good for the few grains that got through)

any suggestions would be great, i'm starting to get to the point of not wanting to brew because it's too frustrating and takes too long. maybe i'm too impatient :)

(hopefully this'll be the first post of many, and i can eventually help somebody else)
G'day Rob7,

I've been having exactly the same problem with mine, but my efficiency has actually improved with the slow crush. The crush is excellent, the efficiency good, just DAMN slow. 6kg in an hour in my case using a drill as slow as I can get it to work. I've widened the mouth of the small plastic hopper and built a bigger one of my own to go over it which holds almost 3 kg of grain. I've set it on a board - basically copied the mods suggested by AndrewQLD in the photo gllery as best I can. If I could even get the time down to 20-30 minutes for 5kgs I'd be happy enough - didn't expect it to be lightning fast. An hour of noisy grinding makes life difficult in our house as well :(

Any suggestions for speeding up the process gratefully accepted.

Hey Shawn,

good to know it's not just me. i just tried the slow speed this morning for a quick trial, and the crush did look better, but i reckon it'd even slower than 6kg/hr. i might have to work on my patience. and maybe build a bigger hopper - that might help, i could leave it to itself for a while then. the current one holds probably 500g.

yeah, the noise is a problem for me too - i'm in an apartment and worry a bit about neighbours, since i start grinding about 8am normally.

yeah, the noise is a problem for me too - i'm in an apartment and worry a bit about neighbours, since i start grinding about 8am normally.

You do AG in an apartment, Rob? How do you manage that? :blink:
not easily

i've got an old canning boiler (~30L, 1800W electric element), first to heat strike water, than sparge water (which then goes into pots on the stove), then to boil the wort. also a 25L esky for mashing. so, i grind into the esky, put the strike water in, heat the sprge water, put that on the stove, then drain the wort into the boiler. not exactly the best system, but it has been just ok. i need a more powerful boiler, which i'm trying to organise at the moment, although i need to concentrate on one problem at a time.

Hi Gough and welcome to Rob7,
It sounds to me like both you guys do not have the mill set or modified to ensure that the top roller gap is WIDER than the bottom roller gap.
If the top gap is narrower than the bottom then it takes "forever" to mill your grain.
Do some searching on this forum, Grumpys, and Goliaths, and you will find a heap of info.
Mine will crack 5 kg in about 5 mins on a drill speed of medium.
That is a little faster than "slow" setting but not flat out on the"fast" setting.
The drill I used is a cordless "Dewalt" brand and it has a variable speed trigger so I can vary the speed during milling.
A good guess at drill speed would be approx' 150 rpm.
Have a look at the hopper on mine in the photo gallery on this forum.
By experimenting with the speed of the drill, I found that faster was "finer" to a point where it started to shred everything.
When you are assessing your mill just compare the crush with some milled grain from a reputable HB shop.
I hope this helps,

Hey Rob7,
I was having the same problem with my Marga when using the notch past 2. I think its because the bottom roller isnt in use and the top two rollers are very close together. I found by winding the dial around so that the '2' is facing the ground (not in an actual notch) and taping the dial in this position gives me a slightly finer crush and the grain flows through a lot better. It takes me less than 20 mins to weigh and crush my average 5kg grain bill.
Also make the slot in the hopper wider and longer.
I have worked out that i get an efficieny around 85-90%
thanks a lot dicko & tim

i'll give that a try later today - i'd read that i wanted the bottom gap to be wider than the top so that it wasn't in use, but it does make sense to have two gaps working.

cheers, i'll let you know the results
Thanks fellas,

My efficiencies have actually been better using the Marga than when I was relying on my HBS' mill, and the filtering/lautering have also improved. Just the speed of the crush as the issue. I think Dicko might be hitting it on the head with the problem revolving around the third roller. I'm using the crush on the 'notch past two' which was suggested as the best option and does indeed give a very good crush. Theoretically according to the little instruction booklet that comes with it the third roller should be automatically disengaged on this setting, but maybe it isn't? How did you get your gap wider Dicko? Can you move it independently? 5 mins for 5kg sounds like heaven at the moment! I'll give your tip a whirl as well Tim.



The theory of the three roller mill is to pre- crush the grain through the first two rollers so it easily goes through the bottom roller at the required crush or gap.

Because the roller dia' of the Marga is relatively small this is necessary for the grain to feed, and as well as the Marga has a very "smooth" knurl on its rollers and wont grip the grain like other mills do.

Tim is on the track when he says to turn the knob to obtain the crush then tape it, or as I preffered to do, remove the knob and drill it so you have some adjustment.
I drilled mine so it is adjustable but you only need a hole to locate the knob in the position that you prefer.

Thanks again Dicko.

I just tracked down your post from ages ago on Grumpy's forum (or at least I think it was you in an earlier incarnation ;) ) and that also helped a lot. Think I'll just tape the adjuster in the position with '2' facing down (as per Tim's suggestion) and give that a go. Hopefully it'll work...

I figured something must be going wrong! Everything was great with it except the time taken to crush. I hope the new setting gives as good a crush as the 'notch past two' because it was a beauty :)

Thanks again - gotta love this forum...

I did a test batch with tape and it went ok. Then i took the knob off and drilled a hole and made it a permanent setting. At this setting it shreds the husks a little more than the just past 2 setting, and its a little finer overall, but i havnt had any stuck sparges or lautering problems and i get really good efficiency.
Rob7 I reckon it may not be your grain crushing that is causing your low efficiency !!
Have you considered your doughing in procedure & temps and your sparging temps .

in the few uses my marga has had, I've been cranking by hand (don't recommend it - i now have a drill) and I've used spark plug gap measure thingys to measure the gap. I read from some guys in the states if you want to do 2 runs, do one at .080 and the second at .060.

I haven't had problems with grain flowing just sore arms :blink:

try this document

marga mill modification
Hi Boots,
Thats a good link as it says it all.
I never did two passes with mine once I got the two gaps set to how I wanted the grain.
Dicko and Tim,

Thanks for your help fellas. I pumped a kilo of grain through this arvo on the suggested setting and it went through in about 30-40 seconds! Top Darts. Crush looks good too. Glad to get it sorted :)

Thanks again. Hope I can return the favour sometime,

I'll add my thanks,

I did a batch this morning, the crush went magically - really quick, excellent crush. My overall efficiency was 78%, which is way above the best i've ever got. brilliant. i've now drilled out a couple of new holes in the wheel, ready to go again tomorrow!

i'm all keen to get brewing again. Happy days!

Cheers guys,
Rob7 I reckon it may not be your grain crushing that is causing your low efficiency !!
Have you considered your doughing in procedure & temps and your sparging temps .

Do you think they do Chatty.

I thought that after my first two batches,how wrong I was ,still they will get there eventually .

I just wanted to see my waving Roo


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