Milling: Difference between revisions

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[[Oxidation]] processes start immediately after milling and can have a negative impact on the subsequent beer quality. Therefore the time between milling and dough-in should be kept as short as possible. Microbiological problems may also become a concern if it is stored for too long after conditioning.<ref name="Kunze"/>
[[Oxidation]] processes start immediately after milling and can have a negative impact on the subsequent beer quality. Therefore the time between milling and dough-in should be kept as short as possible. Microbiological problems may also become a concern if it is stored for too long after conditioning.<ref name="Kunze"/>


Commercial low oxygen breweries fill all areas containing milled grain with inert gas (CO<sub>2</sub> or N<sub>2</sub>). Low oxygen home brewers may also attempt this by flowing inert gas into the bottom of the mash tun and milling directly into it.<ref name="Kunze"/>
Commercial low oxygen breweries fill all areas containing milled grain with inert gas (CO<sub>2</sub> or N<sub>2</sub>).<ref name="Kunze"/> [[low oxygen brewing|Low oxygen home brewers]] may also attempt this by flowing inert gas into the bottom of the mash tun and milling directly into it.<ref>http://www.lowoxygenbrewing.com/forum/viewtopic.php?f=2&t=1025</ref>


With my current system, I have Co2 hooked up from below, mill directly into mash tun, my mill sits on a plate that I made for sitting on top of the kettle, when complete I remove the mill, place the mash cap on top with Co2 still flowing, and continue the purge. With my new system, I'll mill into the mash tun, pull a vacuum, purge, and repeat until all o2 is removed.<ref name="lob1394">[http://www.lowoxygenbrewing.com/forum/viewtopic.php?f=18&t=1394 "milling into mash tun"]</ref>
With my current system, I have Co2 hooked up from below, mill directly into mash tun, my mill sits on a plate that I made for sitting on top of the kettle, when complete I remove the mill, place the mash cap on top with Co2 still flowing, and continue the purge. With my new system, I'll mill into the mash tun, pull a vacuum, purge, and repeat until all o2 is removed.<ref name="lob1394">[http://www.lowoxygenbrewing.com/forum/viewtopic.php?f=18&t=1394 "milling into mash tun"]</ref>

Revision as of 18:47, 15 May 2020

(In progress)

Grain (also called grist) consists mainly of starch granules inside a husk. Before the mash, it must be mechanically crushed using a grain mill in order to break open the husk and expose the starch and enzymes inside. The starch granules are also crushed in the process, increasing their surface area. In general, the crush quality affects the mashing process and saccharification time, lautering, the brewhouse yield, fermentation, the filterability of the beer (beta-glucan content), and the color, taste, and overall character of the beer.[1]

Basic Milling Process:

  1. Set the desired mill gap.
  2. Weigh out the grain on a scale per the recipe specifications.
  3. Optional/recommended: Condition the grain. (See below)
  4. Add the grain to the hopper.
  5. Spin the drive roller to run the grain through the mill (into a container or directly into the mash tun).

Grain Mills

Corona Mill

  • Save your money and get a real mill.

2-roller

3-roller

  • Malt Muncher 3 Roller Grain Mill (MoreBeer)
  • Monster Mill MM3 Grain Mill (MoreBeer)

High-end

Reasons to buy a mill

  • I like, big, husks, and I cannot lie!


Bearings vs bushings? Bushings wear out over time. However, if you keep the bushings lubricated with just a drop of mineral oil every now and then it works MUCH nicer.[2]

I also gave up conditioning after going 3roll and get a really awesome grind. However IMO you have to be turning fairly slowly (100 or less) for ripping not to happen.[2]

Knurled vs fluted?

Stainless steel vs cold rolled?

3-roller vs 2 roller

The 3-roller mill has several advantages:[3]

  • It provides less husk damage, which aids in lautering.
  • It more fully separates the starch from the husk, while providing superior grain feed, even with wheat.

There are also a few disadvantages to a 3-roller mill:

  • Additional power is required to drive it.
  • Brewhouse efficiency may be higher than initially expected.
  • They are generally more expensive.

The 3-roller works by pre-crushing the grain in the preliminary gap between the top two rollers, then opening the husk to expose the crushed kernel in the secondary gap with the third roller. The top gap is fixed at approximately .060" which easily pulls in both wheat and barley, softening the starch without tearing up the husk.[3]

Gap Setting

The optimal mill gap setting is dependent on your mill, your brewing system, and other factors. Therefore there is not a one-size-fits-all gap setting. For some brewing systems, the husks must be disintegrated as little as possible during milling because they are required for lautering. For other brewing systems such as "Brew In A Bag" (BIAB), the grain can be very finely milled if desired. Less well modified malt requires finer milling.[1]

A feeler gauge should be used to adjust the gap setting.

I have a three roll mill and am recirculating so I use 0.049" for the gap.[2] I have a 2 roll monster mill set at 0.034”. If I condition and slow mill it’s a good crush, but if I just go quick at that gap, there’s too much flour.[2]

Everyone always talks about gap but I really feel that milling speed has more effect on a good crush then the roller spacing, or conditioning.[4]

Driving the Mill

Motor vs drill vs hand crank vs mule?

100RPM amazon gear motor ? I assume you're referring to the Makermotor gear motor? I bought the 50 rpm because I was concerned the torque of the 100 rpm, at 2.2 ft-lb, wouldn't be enough. I'll be interested to hear how the 100 rpm motor works for you because 50 rpm is painfully slow.[2]

I aim for about 120 RPM.[2] I also like to mill slower, about 70 is what my motor puts out.[2]

The best speed to run home brew mills is around 150-250 RPM. Running it faster will create more flour, so slower is generally better, whatever works without your drill or motor stalling. It usually takes a little more torque to get the mill going than to keep it going, so you will have to give it some more power to start the mill, and then slow it down once you are milling.[3]

Other Considerations

Oxidation processes start immediately after milling and can have a negative impact on the subsequent beer quality. Therefore the time between milling and dough-in should be kept as short as possible. Microbiological problems may also become a concern if it is stored for too long after conditioning.[1]

Commercial low oxygen breweries fill all areas containing milled grain with inert gas (CO2 or N2).[1] Low oxygen home brewers may also attempt this by flowing inert gas into the bottom of the mash tun and milling directly into it.[5]

With my current system, I have Co2 hooked up from below, mill directly into mash tun, my mill sits on a plate that I made for sitting on top of the kettle, when complete I remove the mill, place the mash cap on top with Co2 still flowing, and continue the purge. With my new system, I'll mill into the mash tun, pull a vacuum, purge, and repeat until all o2 is removed.[6]

I pre-underlet CO2 and some during milking too. I don’t run it constantly because the regulator starts to freeze up and it also starts to freeze my MT ball valve and chill the FB. The net result, if I run too much CO2, is that I come up short on strike temp because of the water passing through a super-chilled ball valve. Then, when milling is done, I turn the CO2 back on and then remove the platform to which my mill is mounted and cap the grain. Some air will get in. -- solution: Get a cheap hair dryer, connect it up to blow on your regulator, no more freeze ups.[6]

My process was similar to others. My mill is mounted to one of those round pine table tops (identical to the one shown above), large enough to cover the entire MLT. -Purge MLT from the bottom for 10 minutes with grain in the hopper. -Mill with CO2 continuing to flow. -Add grain to hopper as needed. My goal was to keep it pretty much topped up so the CO2 I was purging with might purge the grain in the hopper too. Not convinced it was effective, but made me feel better.[6] -When milling complete, remove mill, place mash cap and lid. -Move CO2 connection to MLT recirc return and continue purging. -Underlet -Turn off purge once water gets close to the level of the return connection. -Finish underlet.

I mill into an unpurged empty vessel. I purge while the water preboils and chills.[6]

Purging isn't an absolute requirement, but it is a good tweak to the process. I wouldn't get hung up on it initially. After you've got the rest of the process down its something to look at. The point of purging is dilution. Unless you are using some type of displacement method the best thing you can do is dilute whats there. Realistically you won't be able to put enough of a vacuum on any brewing vessel to do an effective purge. Your best bet is continuous flushing with inert gas.[6]

"Flaked" or "rolled" adjuncts do not need to be milled, although they can be run through the mill with the rest of the grain if it is convenient.[7]

Sieve testing

Conditioning the Grain

Aside from cellulose, the husks also contain polyphenols and other compounds that create an unpleasant bitter taste and have a negative effect on the colloidal stability of the beer. Dry husks fragment easily and lautering becomes more difficult if the husks disintegrate too much. However husks become more elastic when they are moist, making them easier to protect and subsequently making lautering more rapid.[1] Wetting the grain is called "conditioning". The goal is to increase the most content of the husk by approximately 2%.

http://www.lowoxygenbrewing.com/uncategorized/grain-conditioning/

Process:

  1. Add water to a small spray bottle. Generally the amount of water should be about 1-2% of the weight of grain.
  2. Spray the grain evenly while stirring (e.g. with your hand) until the grain becomes pliable.
  3. The grain may be milled a few minutes after wetting.

Advantages:

  • The grain can be ground more thoroughly (tighter gap).
  • Husk volume increases (looser grain bed).
  • Yield and attenuation are increased.
  • Conversion is faster.
  • Reduces dust.
  • Decreased risk of dough balls.[4]

Disadvantage:

  • Requires labor.


I regularly use 24+ pounds of malt, weigh it out in buckets, then pour a thin layer into a large plastic tub, spray it down, pour another layer, spray it, and repeat until done. Easy peasy, works great.[2]

I do 100L batches with malt bills anywhere from 20-30+kg and still condition my grain. I just have a large tote and a flexible misting nozzle for my sink hose. I turn the mister on and stir with my mash paddle since it no longer stirs the mash. Works like a charm and is actually easier and more enjoyable than spraying 7kg with a spray bottle, this method doesn't involve any hand cramps.[2]

I have the mm3 pro powered by a low speed drill. I don’t condition any more because I find it’s not necessary. But the conditioned crush was absolutely beautiful. Endless piles of barely torn husk. The mash wasn’t noticeable better though. So I eliminated that 10 minute effort from my brew day and focus elsewhere.[2] I found it made a beautiful crush but didn’t make any noticeable difference in dough balls or lautering so I stopped wasting my time. Maybe if i was doing batches with 10lbs of grain I might do it, if only for the dust control, but it’s a huge pain to do with my typical 20-33lb grain bills.[4]

All I do for conditioning is spritz the grain while using my hand and arm to stir the measured grain in the bucket. The extra 5-10 minutes it took, I feel, was worth the elimination of doughballs and less mess on the bottom of the mill.[4]

I still do mine. I like the qualities of the crush (more intact husk, less dust, etc) enough that I have never stopped. Same procedure as you, spray bottle and stir with my hand.[4]

I still condition. I do it now mostly to keep the dust down during milling. The quality of the crush didn't change much for me pre/post conditioning and I never had doughball problems before conditioning, either. But, I mill by hand so my RPMs are not high and thus I'm not shredding to powder.[4]

I still condition my malt for the reduction of dust in my mill like you and I believe I get a better crush as I'm still only using a Cereal Killer mill, although I simply take 30-50ml of pre-boiled water and pour it on the malt and mix it up by hand.[4]

I still condition as well. Doesn't take much time to do, and I am getting good results with it.[4]

I also condition the grain. Stirring with spoon in one hand, spraying with the other. Takes about 1-2 minutes, then I let it sit for 7-10 minutes prior to milling. Keep the dust to an extreme minimum as well as keep the husks from shattering - caveat is that I have a 2-roller mill.[4]

I stopped doing it because I was losing a lot of efficiency. Like 10-15 points solidly. Stopped conditioning and I'm back in the right range again. Haven't touched the mill gap setting so I have no idea why this is the case.[4]

my mill isn't the greatest, and it seems to grip the conditioned grain much better and therefore mills faster even at the same speed.[4]

grain conditioning is helpful with keeping the husk more "intact" to protect the acrospire and polyphenols from being exposed to air right off the bat which helps to minimize some oxidation prior to dough-in. ??

To be clear, I don't measure it. I just spray some on and mix it up, then add more if I think it needs it. That's what I'm doing for better crush. I can almost do it by feel. It's doesn't seem dry and lose. It's not sticky or clumpy either. It stops feeling dry and friable.[4] I think I notice it most in the sound of it. If you pick up a bunch, the sound it makes as it flows back down shifts a bit and I think that is what I'm really going by. I also don't bother measuring conditioning water and go by feel.

Our mills don't like wet grain.[4]

When I started conditioning I felt like the kernels slightly expanded and didn't want to go through the gap as easily and so I did widen my gap.[4]

Adding a Motor

Coming soon?

http://www.lowoxygenbrewing.com/forum/viewtopic.php?f=2&t=694

See Also

References

  1. ↑ a b c d e Kunze, Wolfgang. "3.1 Milling the Malt." Technology Brewing & Malting. Edited by Olaf Hendel, 6th English Edition ed., VBL Berlin, 2019. pp. 203-218.
  2. ↑ a b c d e f g h i j "Choosing a malt mill."
  3. ↑ a b c "FAQs" Monster Brewing Hardware. Accessed May 2020.
  4. ↑ a b c d e f g h i j k l m n "Revisiting grain conditioning."
  5. ↑ http://www.lowoxygenbrewing.com/forum/viewtopic.php?f=2&t=1025
  6. ↑ a b c d e "milling into mash tun"
  7. ↑ "Brewers Barley Flakes." Product Information Sheet, Briess, 2019.
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