Wet Milling?

Discussion in 'Grain, Malt and Adjuncts' started by Lionman, 13/10/17 at 4:39 AM.

 

  1. Lionman

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    Posted 13/10/17 at 4:39 AM
    So I was pondering a machine that milled and doughed in at the same time and looking on the net for ideas.

    I came across the idea of wet milling, where the grist is moistened before it's milled. Apparently it makes the husks more resilient to the milling process which leads to easier lautering and sparging and a slight bump in efficiency.

    Has anyone done this? Is it worth the effort?

    And back to the original idea, a machine that you could stick on top of your mash tun with a full batch hopper that simultaneously milled and mashed in would be pretty sweet. I was thinking a pump that on the bottom side of the mill that pulled up liquor into an auger that pushed the water/grain mix back down into the tun. No more fishing for dough balls, sore hands from stirring, breathing in grain dust etc. Am I crazy?
     
  2. razz

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    Posted 13/10/17 at 4:43 AM
    Hey Lionman. If you do a bit of reading you will find that wet milling is one thing (like a larger scale brewery would do to avoid doughing in problems) compared to malt conditioning, which is what some members here have done. Use the search tool for “malt conditioning” I’ve done it myself and it works very well.
     
  3. n87

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    Posted 13/10/17 at 4:58 AM
    I have contemplated milling straght into the strike water... the one thing that stopped me is steam.
    Unless your grain is saturated, you will end up with flour. That stuff, if find, is statically attracted to the mill.
    Think of the following, coarse, equations

    Flour + water = dough
    dough + heat = bread

    So with the steam rising from the strike water, I would guess you would be gumming up your mill.

    Maybe not hot enough to make bread... but dough is bad enough ;)
     
  4. razz

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    Posted 13/10/17 at 4:59 AM
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  5. pnorkle

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    Posted 13/10/17 at 5:32 AM
    I seem to remember a similar thread about wet-milling from some years back. I could be wrong, but I think Ducati Stu was responsible for it.
     
  6. Lionman

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    Posted 13/10/17 at 6:52 AM
    Yeah I understand they are two different things, sorry, I used the wrong term. The terms are used interchangeably by some homebrewers it seems. I have read a few guides on malt conditioning, I am interested to know peoples opinions on the subject. I think I will give it a go.

    I'm also interested in actual 'wet milling' or something similar. It looks like the term is also used in industry for certain ways fop rocessessing grains outside of brewing so it maybe isn't the right term.

    I would think if under the mill the grain is isolated from the mash tun except for a tube with an auger in it that there would be a limited amount of steam making contact with the internals of the mill itself and it might not be an issue.

    As in something like this awesome sketch. Haha.

    wet mill.jpg
     
  7. technobabble66

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    Posted 13/10/17 at 8:01 AM
    Correct.

    I do grain hydration or malt conditioning prior to milling.
    Works brilliantly - maintains integrity of husk so it's like adding several handfuls of rice hulls to the mash. Really helps with flow through the mash bed.
    It can mean slightly greater workload on the mill - so if cranking the handle by hand you might slightly notice it, however if you're milling with a motor and you doing a LOT of grain then the extra workload may be significant strain on the motor, say with 150kg at a case swap resulting in a burned-out motor ... :oops::mad:


    The general rule (from DucatiBoy Stu, i believe) is ~10mL of water per 1kg of grain.
    I use a sprayer while i pour the grain from 1 bucket to the next, then stir by hand for a minutes, then leave for 2-5mins while it softens/hydrates the husk, then mill away.

    NB: I milled several kgs with DJ_L3thal a few months ago on his MM3 mill. A top quality mill like that probably doesn't benefit from the grain hydration as much as my crappy KK mill, as the "nip angle" (?terminology?) is much better, so it does a proper job of crushing the inside of the grain without tearing the outside.
     
    Last edited: 13/10/17 at 8:10 AM
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  8. Lyrebird_Cycles

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    Posted 13/10/17 at 8:38 AM
    Wet milling was a thing a many years ago, it was effectively mashing in whole malt and milling the mash.

    Basically never used any longer.
     
  9. MHB

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    Posted 13/10/17 at 9:09 AM
    Bluetongue had a shiny new Steiner wet mill, whole brewery is gone now, but it was a pretty sexy brewhouse.
    Might be making a comeback. (Edit - wet milling not Bluetongue)
    The mill at malt shovel was a wet mill, they had bypassed the water feed, and put it on an auger, I think it went from there to a malt hydrator, then pumped with a progressive cavity (mono) pump to the mash/kettles, haven't looked at that brewery for a decade or so - might not be contemporary info.

    Liomman - never try to "suck" hot water, it will cavitate like a daemon. I would also be very suspicious of a mill that wasn't designed to run wet, I suspect water will be leaking out everywhere, if nothing else look had and long at the bearings and your electrical safety, trying to get the right balance of grain flow and water so the result is at the right temperature and L:G, that you don't run out of water part way through, that you don't have too much water left over but enough to clean any malt out of the mill...
    It would be a problem best left to large brewing concerns where they can afford to do a lot of process control for what to a home brewer would be a small return.
    Mark
     
  10. Ducatiboy stu

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    Posted 13/10/17 at 11:01 AM
    Correct. And works wonders to keep your husks in tact which makes for better sparging...and gives a few more eff% points :)

    The trick is not to use to much water
     
  11. Lyrebird_Cycles

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    Posted 13/10/17 at 12:48 PM
    Since you asked: No, your terminology is a bit confused.

    For a given roller gap, nip angle is a function of roller diameter so since the two mills have roughly the same roller diameter they'll have the same nip angle at the same setting. IIRC they are both about 38mm so the nip angle will be far too high.

    Any roller with a diameter below ~250mm will have a nip angle higher than the optimum for malt milling. This can be partially compensated by good flute profile and having the flutes twist in the same orientation so that they oppose each other at the nip point. This may seem paradoxical but remember that the front of one roller meets the back of the other.

    The smaller the roller the harder this is to do, by the time you get down to under 40mm you need to overcompensate with aggressive knurling or fairly deep cutting profiles. The KK mill uses the first, the MM the second. From what I've seen so far, the knurling causes more damage to the husk.
     
    Last edited: 13/10/17 at 12:56 PM
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  12. Danscraftbeer

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    Posted 13/10/17 at 1:09 PM
    I like the results some people have posted here when they just slightly hydrate their grain before milling.
    I mill my own and prefer dry for longer mileage of the mill. Dry is cleaner. If you over hydrate your grain you get gunge build up on your rollers. Like sugar in the engine, bad!
    So although I've seen sexy pre lightly hydrated milled grain porn photos here I still haven't re hydrated grain pre milling.
    $0.02
     
  13. Ducatiboy stu

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    Posted 13/10/17 at 1:17 PM
    And the trick is not to over hydrate. You want just enough water that the husk absorbs it all. If your getting gunge then it is to wet

    Ideally, when you use the " stick my arm in the bucket and mix the fuxk out of it" method, you should have no water in the bottom of the bucket and an almost bone dry arm

    Its a fine line and depends on humidity, temp, wind, the solar system, some bloke called god, monty python, unicorns and beer

    And as for mills, speed is also a big factor. My 50mm rollers ( SS knurled ) run at about 180rpm and thats about as fast as you want. Mills 5kg in about 1min. Smaller rollers need even slower speeds or you just tear the grain apart
     
  14. Danscraftbeer

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    Posted 13/10/17 at 2:05 PM
    and then even if you tare the grain apart dry it still makes good wort when you re hydrate it post milling. Vorlauf is good.
    Not to say you may get better results re hydrating, to be clear...
     
  15. wynnum1

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    Posted 13/10/17 at 9:32 PM
    Strike water is at a temperature that after the grain is dumped in quickly drops in temperature where if you milled into strike water that would change how temperature would need to be managed.
     
  16. n87

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    Posted 13/10/17 at 9:41 PM
    That is also true, if you have a recirc rig, you would just have the strike water at mash +1 and recirculating till about 3/4 was in.... depending on how wet your mash is.

    To combat gumming up the mill, you could have it to one side of your mash run with a half pipe chute, so in theory, no steam would travel back up it to the mill.
     
  17. Ducatiboy stu

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    Posted 13/10/17 at 9:56 PM
    Strike water needs to be about 8*c higher than your target mash temp*

    *YMMV depending on grain temp etc...but 8*c is pretty close
     
  18. n87

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    Posted 13/10/17 at 11:45 PM
    But if you are adding the grain gradually... say 5kg/min, then the strike would be too hot for the first grain.
    if you were recircing, you could keep the temp... maybe... around mash temp.
     
  19. Ducatiboy stu

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    Posted 14/10/17 at 1:38 AM

    This is true, but regardless, if you are not introducing a little bit of heat to the mash, the cold grain will still pull the temp down
     
  20. Jack of all biers

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    Posted 14/10/17 at 2:32 AM
    As has been stated there is a difference between 'wet milling' and 'malt conditioning' and I'll add that there is the more modern version called 'steep-conditioned wet milling'. It is briefly described in the Malt book (Malt-A practical guide from field to brewhouse 2014). It is basically having the grist sprayed or briefly (60 seconds or so) dunked in hot water for the husks to become pliable and more water is added at the crushing stage, which is pumped to the mash vessel at Sacc. temp. These types of mills are purpose built for task, with the right types of corrosion resistant alloys and CIP systems. They are used by breweries that operate on efficiency/cost basis, as the whole grist can be crushed and up to mash temp in 20mins or so (as opposed to traditional 'wet milling' where the grist can be first steeped for up to 30mins before crushing commences) and it allows increased capacity in the lauter tun. An example of such a commercial mill.

    As you've acknowledged 'malt conditioning' is more of interest to you.

    To your original idea of having the mill above your mash tun filled with hot water. I would say that unless you want layers of gunk stuck to your rollers, and the corrosion that will eventually set in, I wouldn't do it in the way you have sketched or proposed. I think it would be better for your equipment to 'malt condition', if you will, mill into a bucket or other vessel and then tip that into a funnel type device that slowly (with adjustable control if you like) adds the grist to the liquor (which can be recirculated or mechanically mixed).

    To avoid the negatives of mash stirring, as you posted above, a mechanical mixing of your mash may be preferable. Lyrebird_Cycles has made a direct heated and mechanically mixed mash tun, but I can't remember the thread he posted pics of it (kills two birds with one stone with the easy step mashing ability). Instructions on a home built mash mixer here. Or if you'd rather buy one ready made then the Germans sell the mixers at home brew scale though at 258 Euros plus postage, you'd really have to hate hand mixing.

    EDIT - Lyrebird_Cycles set up located here
     
    Last edited: 14/10/17 at 2:43 AM

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