Are you crushing too fast?

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I recently came across this in BYO"

A common drill motor can motorize most mills. The problem with this approach is, while it works, it simply works too fast. Optimum roller speed for small homebrew mills is 150–200 rpm. Drills and most AC motors run at 1,750 rpm (U.S. 60 cycle AC.) The answer is to use pulleys and belts or an expensive gear reduction motor to run your mill more slowly.

http://byo.com/departments/1123.html

My only remedy right now is to use the torque setting on my drill and reduce the trigger.


Might explain a few points of efficiency and some individual differences between brewers with identical settings on the same mill.
 
My only remedy right now is to use the torque setting on my drill and reduce the trigger.

Same here. I have been wondering about this in the past and the BYO mention supports my suspicion. I'll ease up on my RPMs and see what happens. Then again, Bobby_M crushes fast and has no problems...
 
The article doesn't really say why faster is bad. My dewalt's low speed is 300rpm unloaded so I'd imagine it bogs to abotu 250 during the crush. I suppose I could slow it down by half triggering it but ehhh..
 
I just bought a new mill (see here: https://www.homebrewtalk.com/showthread.php?t=65631) after ruining my old JSP with my handheld drill... didn't know it until after powder-izing 18 lbs of grain. Doh!

Anywho, I just bought a 12" sheave and a 1.5" sheave along with a 48" 4L belt to reduce the 1/2 HP 1725 RPM motor down to ~ 200 RPM. Hopefully gonna build my milling station next weekend...
 
I hit 90% last time running basically full-bore.

The only thing that would make sense to me is if a fast crush is shredding the husks too much for them to form an effective filter bed, but it seems the downside would be difficulty in sparging, not an efficiency reduction. That, or maybe excessive tannin extraction. All theoretical, though; I know Bobby's spoken at great length about NOT having those issues with his high-efficiency mash, and I haven't noticed anything myself.
 
I've wondered about this, too. I've a Barley Crusher on which I use an old electric drill that is difficult to control the speed with the trigger. It's generally too fast. I'm going to try slowing it down next time by using my Rigid battery-powered drill, but FWIW I've always got about 92% efficiency, both from grain crushed at the LHBS and the Barley Crusher with my too-fast drill.
 
My 5-year old is in charge of running the Barley Crusher, and he likes to use the corded DeWalt drill. I'll read him this article from BYO and see what he thinks. Chances are, it won't change his mind any. :D

Helper_3-1-08.jpg
 
I run my corona-style mill at full speed on the drill and I don't have any problems with stuck sparges (batch or fly) and my last batch hit 90% efficiency.

I'm gearing up my new monster mill now and I plan to run it first at 400RPM and evaluate the crush, if it doesn't look decent I'll probably drop down to 200RPM.
 
I use a Snap-on 1/2 drive air drill. Not sure what the speed is but I would say that it's about 400 or so. I'm getting low 80's with that and the stock setting on the BC Mill.
 
I use a cordless dewalt 14.4v XRP with my BC. I never get stuck sparges, even on wheat beers (and I never use rice hulls), and my efficiency is routinely around 78-82%.
 
I use a cordless dewalt 14.4v XRP with my BC. I never get stuck sparges, even on wheat beers (and I never use rice hulls), and my efficiency is routinely around 78-82%.

Exactly the same here, but I use a 1/2" corded drill that I run at about 3/4 speed, crushing in my Corona-style mill. I use to crush slower (I'm not sure why) and my efficiency has only gone up.

I'm going to have to try back-to-back batches with the exact same grain bill grinding one slowly and one quickly and see if there is any difference.
 
I make sure my batteries are at full charge and I run my Crank N Stein at full RPMs. I don't know how crushing the grain faster is going to mess up my crush. I get fantastic looking grain, and my husks still look like they are full and intact.

I get 80-82% efficiency normally and no stuck sparges. Im going to try it next time though. Im going to crush a few pounds at full RPM, then do a few at a very slow speed. Im betting you won't be able to tell which is which.
 
My guess is the manufacturer recommendations are based more on prolonging the life of the bushings than the quality of the crush. If the husks start to shred, just back off the gap slightly and it should take care of it.
 
I use a drill too, reguraly getting around 80% efficiency and never any problems. But I suppose you could get an inverter and a 150 rpm DC motor? Maybe even a variable speed for some more freedom?
 
I still have a heavy duty paper shredder motor that I am going to convert. Nice and slow, but not too slow methinks.
 
Interesting. I'll try slowing things down a bit on my next one and see how it goes.
 
POST HI-JACK. John Beere. Did I read your post right. You just BOUGHT A NEW mill. What you doing with your old one? Want to sell it? PM me if you do. thanks.

Chris.
 
I often hand crank too... Oh wait, we're talking about grain mills!

I just built a crusher and soon will try it. I could use my cordless drill, but I also got an old AC drill with variable speed, that you can set the max with a small thumbscrew. Seems perfect to me. If it's got the guts...

I'm also building a hand crank for when I only got a little bit to crush and don't want to dig out the drill (or in case the power goes out and I want to brew...)
 
I've wondered about this, too. I've a Barley Crusher on which I use an old electric drill that is difficult to control the speed with the trigger. It's generally too fast. I'm going to try slowing it down next time by using my Rigid battery-powered drill, but FWIW I've always got about 92% efficiency, both from grain crushed at the LHBS and the Barley Crusher with my too-fast drill.

Hey guys, keep your eyes out in Goodwill and garage sales for an old-school half-inch drill. Mine's a black & decker. It's a single-speed, but that one speed is about 250 rpm. It's a slow-moving, high-torque piece of equipment that's useless for almost everything except motorizing you mill ... back when I was young and stupid I used it to sink deck screws. No brake, but you'd think that wouldn't matter with deck screws, right? Wrong ... I overdrove a bunch of 'em before I got the hang of it.

cheers!

--Finn
 
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