# New grain mill - hand crank vs drill power?



## Adrianc5 (29/10/15)

I have just bought a grain mill, nice 2 roller model from iBrew on the goldie. I did my first batch with it using a cordless drill to drive the mill roller.

My mash efficiency was down (~62%) on what I had previously (~70%), which I kind of expected as I thought it might take a bit of dialling in. I thought the grind looked ok, no photo though unfortunately. I made up the shortfall with some DME in the kettle so no dramas with the beer fortunately! The mill gap was around 1.35mm which is probably too high so I'm hoping changing this to around 1.0mm will sort out the efficiency issue but...

My question is - has anyone experienced a difference when a grain mill is power driven as compared to hand cranked? If so, are the recommended maximum speeds for a grain mill drive?

Cheers,

Adrian


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## hairydog (29/10/15)

Hey Adrian,

I hear around 200 RPM is the optimum speed,i have also bought a new mini mill and set the gap to about 1mm,i run it on a battery

drill which is about close to speed when loaded with grain through the rollers.5kg of Maris Otter went through nicely and efficiency was

about 75% BIAB with spare,can't comment on the difference between hand cranking but presume lowering gap distance will do the trick.


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## Crusty (29/10/15)

Depending on your brewing equipment, ie: if you recirculate your mash or not, you can go a lot finer. 0.9-1.0mm is a pretty good crush & should yield you pretty good efficiency without excessive flour. I use a drill for my MiniMill & the slower you go the better. Hand cranking is obviously slow so aiming for something similar with the drill, or as slow as you can go effectively is what you should be aiming for. Knock back the mill gap to your suggested 1.0mm & I reckon you'll be happy with it.


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## Adrianc5 (29/10/15)

Sweet, thanks for the quick feedback guys.


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## Weizguy (29/10/15)

I'm quite happy to hand crank my grain through the mill. Takes a bit of time with up to 8+ kg of grain, but at least the crush is good, and the husks are not torn due to high speed.
Getting 90%+ since slowing my sparge. Same mill @1.0mm gap
It IS an awesome mill though.
Try a batch with a drill and one hand-milled and see if there is a detectable difference.


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## welly2 (29/10/15)

You and me both, Les. I've milled up to 6kg of grain manually and it didn't take that long to be honest and efficiency was up there around 80%. Can't say I'm too bothered about spending time hooking up a drill to it, not at this stage anyway. When it becomes a chore I'll automate it.


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## Weizguy (29/10/15)

Just checked my records and have milled up to just short of 12 kg by hand. Some fast thinking to allow all the grain to fit in the mill. I think it overflowed the bucket, so please be aware when planning to mill.


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## spog (29/10/15)

Adrianc5 also take into consideration the size/ capacity of the hopper , if you have a blockage and have to remove the hopper you may end up losing valuable grain trying to clear it.
Perhaps design some sort of shut off slide to stop spillage and post it here to help others or build a small hopper .


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## woodfired (30/10/15)

Les the Weizguy said:


> I'm quite happy to hand crank my grain through the mill. Takes a bit of time with up to 8+ kg of grain, but at least the crush is good, and the husks are not torn due to high speed.
> Getting 90%+ since slowing my sparge. Same mill @1.0mm gap
> It IS an awesome mill though.
> Try a batch with a drill and one hand-milled and see if there is a detectable difference.


Morning Les,

You mention better efficiency since slowing the sparge. How slow are we talking for total sparge time? Do you stir or cut the bed during this sparge? 
I noted that Sean had the cutting blades rotating slowly up at Murrays on Saturday. He said it was to avoid channelling. 
Your stout is still sitting in the fridge. I'm waiting for the right occasion. :chug:


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## woodfired (30/10/15)

Sorry I forgot to add my comments directly on this thread.

I mounted my mill on a large timber base so that I could use my battery drill and I positioned it on the base so that with the drill in place it is balanced for weight. Works very well. It achieves a good crush without any husk shredding. My efficiency is only about 70% but after Les' comment I think I may me going to fast on the sparge.

I have the gap set to 1mm also. One tip my cousin gave me that has been useful is that if you have any harder grains like wheat and rye, mix them with your base malt and they will crush easier because the mill doesn't have to crush the hard grain across its entire width at any one point in time. I trialled this when I got my mill and it was very true. I had to up the torque setting on my drill for wheat and that was the only time I noticed it tearing the grain rather than crushing it. Even at 50/50 this was alleviated.


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## warra48 (30/10/15)

I've recently gone back to hand milling my grains. 5 to 6 kg milled in no more than 5 minutes is not a hardship.

I agree with Les the Weizguy, and my experience is very similar.
My gap is set at about 1.1 mm, and hand milling leaves the husks intact much more than they were when using a drill. The drill milling used to tear the husks, probably because I just couldn't slow it down enough.

My mash efficiency always comes in at 90%+, but the biggest difference has been in run off and sparging. Since going back to hand milling, the time taken has reduced by half.


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## woodfired (30/10/15)

Now I'm thinking my run off and sparge are too fast. I think my face must look a bit like Sergeant Schulz in you logo Warra.

I fly sparge most of the time. and probably only take about 10 to 15 minutes total. I then leave a 5lt jug under the outlet while the boil begins and usually collect another couple of litres.

So many variables to consider, but the reasons I've not been to worried about the 70% I'm getting is that it seems to be a pretty commonly quoted efficiency level. Also I thought that having raised the temperature to 75 degrees for mashout, that the subsequent viscosity reduction would mean the sugars and wort would drain and rinse out of the grain more freely.

What techniques do you guys use and what time frames for a typical strength and grain type beer?

My apologies if I should have started a new thread for this. I'm not quite sure of the etiquette for that yet.


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## warra48 (30/10/15)

I batch sparge, with a mashout addition at completion of the mash, runoff, top up again, and sparge. Total time taken is about 45 minutes.
Pre-boil I generally collect 35 litres in the range of 1.035 to 1.045 SG, using an average of about 5kg grains.


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## Weizguy (30/10/15)

woodfired said:


> Morning Les,
> 
> You mention better efficiency since slowing the sparge. How slow are we talking for total sparge time? Do you stir or cut the bed during this sparge?
> I noted that Sean had the cutting blades rotating slowly up at Murrays on Saturday. He said it was to avoid channelling.
> Your stout is still sitting in the fridge. I'm waiting for the right occasion. :chug:


About 600 ml/min. Your batch size will determine how long that takes.
Don't usually cut the bed to avoid channelling, as my bed's nowhere near as deep as the one at Murray's

As for the stout. It's still a weizenbock.



woodfired said:


> Sorry I forgot to add my comments directly on this thread.
> 
> I mounted my mill on a large timber base so that I could use my battery drill and I positioned it on the base so that with the drill in place it is balanced for weight. Works very well. It achieves a good crush without any husk shredding. My efficiency is only about 70% but after Les' comment I think I may me going to fast on the sparge.
> 
> I have the gap set to 1mm also. One tip my cousin gave me that has been useful is that if you have any harder grains like wheat and rye, mix them with your base malt and they will crush easier because the mill doesn't have to crush the hard grain across its entire width at any one point in time. I trialled this when I got my mill and it was very true. I had to up the torque setting on my drill for wheat and that was the only time I noticed it tearing the grain rather than crushing it. Even at 50/50 this was alleviated.


For wheat or rye. I usually run them through the mill separately to the barley, and mill them twice. Yeah, it's tougher to mill by hand, but not impossible (by any means).
A fine crush is a good thing for wheat, as there is no husk on it, and therefore, it's more important than usual to preserve the husk on the barley that is crushed for the same batch, for a good lauter.


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## Screwtop (30/10/15)

Interesting reading. I use a drill with a ghetto speed control (cable tie around trigger and handle) :lol: Over nearly 8 years using this mill I have found that slow gives a better crush, gap is 40thou or 1.016 mm.

Much like Les and Warra my mash efficiency is usually in the 90% range....... SO LONG AS I: 1. Keep stirring to a minimum 2. Sparge/drain slowly over about 40 min for a double batch (50 odd litres to the kettle) a little more than 1 L/min.

If the grist is milled fine then efficiency can suffer if the mash is stirred vigorously or to often as flour and small particulate matter is stirred into solution and then settles into a muddy layer over the top of the mash. This prevents the mash from draining properly, wort channels down the sides reducing efficiency. 

If you must stir, then turn the mash gently rather than beat it!

Screwy


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## woodfired (30/10/15)

"As for the stout. It's still a weizenbock."

sorry. Had a few more beers once I got home that afternoon. I remember you telling me that now.

I'm usually aiming for low 30's to the kettle, so my 10 to 15 minutes is way too fast. I'll slow that down and aim for 50 minutes next brew.

Great tips on the wheat and rye. I'm looking forward to trying my previous brews on each of those to see the difference crushing separately makes.

You mention that a fine crush is a good thing for wheat. Do you change the mill setting? or does just running through twice achieve what you are after?


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## Weizguy (30/10/15)

woodfired said:


> "As for the stout. It's still a weizenbock."
> 
> sorry. Had a few more beers once I got home that afternoon. I remember you telling me that now.
> 
> ...


The twice-milled wheat seems to do the job, with the standard 1.00 mm setting. Sometimes I mix it into the barley and mill them together.

If you get your grain from the Brewman, he can seal the bag in two places, separating the wheat from the other grains. Just tell him you want the grain packaged using the 'MHB" packing technique, that he uses for me.


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## crd0902 (12/12/15)

Hi all, figured I'd post in here as its about milling and grain crush. First time crushing and just looking for advice as to if I'm on the right track. It's set at keycard width, hand milled and my mash tun has a copper manifold. Cheers 

Chris


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## Brewman_ (22/12/15)

Les the Weizguy said:


> If you get your grain from the Brewman, he can seal the bag in two places, separating the wheat from the other grains. Just tell him you want the grain packaged using the 'MHB" packing technique, that he uses for me.


Hi Les, just seen this.
Not sure if this should be the MHB or Les the Weizguy packaging standard. I think Mark, (MHB) Pioneered it and you have made it your own.

There is a whole lot that goes into how I crack the grain that many would not be aware of. It's the benefit of a commercial mill, and offering a variable crack. You can crack to pretty much any standard, and each brewer has their own spec, and this is the Spec that Les has.


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