Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

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Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by chris2012 » Mon Apr 22, 2019 7:00 pm

Just wondering if the Maltmiller fine crush is ok for use in a mash tun, with a false bottom?

Cheers!

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by Jocky » Mon Apr 22, 2019 8:36 pm

I expect it should be. I have a false bottom and crush my own grain pretty fine. Just make sure it drains freely.
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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by chris2012 » Mon Apr 22, 2019 9:17 pm

Cheers! Will get some of that next time then.

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by guypettigrew » Mon Apr 22, 2019 9:57 pm

Never tried the fine crush. I always buy the ordinary crush. Works fine in a false bottomed mash tun and gives over 90% mash efficiency.

What advantage do you think there would be to the fine crush over the ordinary crush?

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by chris2012 » Tue Apr 23, 2019 12:05 am

I was wondering if my efficiency might increase. Recently I got around 1.050 OG from grain from another supplier, the expected OG was to be around 1.066. However I do know I mashed lower than I should have, only hitting around 63 C tops (I calculated the strike water temp around 71C, when I filled up the mash tun with water on the grain, it only hit around 61C and I had to add lots of boiling water to even get to 63C, so much so, that I didn't sparge, as there was so much liquor already).

Could there be other reasons for a low mash efficiency though, apart from incorrect mash temp. and lack of sparging heh.

Thanks

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by Kev888 » Tue Apr 23, 2019 9:47 am

If you didn't sparge then that will likely be by far the main reason for getting lower gravity results. Small differences from the crush and so on are going to be minor by comparison; probably not worth worrying about if the basics didn't come together, really.

The fine crush would likely work if you have no issues with the mash sticking, though keep in mind that finer crushes can hamper efficiency as well as improve it, depending on the system. Though you'd obviously need other things to come together consistently to be able to tell if you were getting a difference from this.
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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by guypettigrew » Tue Apr 23, 2019 9:52 am

The best way I've found to calculate strike temperature is to use 'Andy's strike temperature calculator' on here. It gets me the right mash temperature every time, as long as I stir the mash really well.

Not sparging could easily reduce your mash efficiency, but perhaps you're doing full volume mashes and draining really well.

Other factors such as pH and water treatment may affect your efficiency, but not to the degree you've experienced.

There can also be a loss of extract, ie reduced efficiency, when you drain from the boiler. Although my three vessel system gives me good mash efficiency (over 90%), my overall efficiency drops to below 80% due to wort inevitably left in the boiler with the hops and trub. Yes, the hops could be squeezed or sparged, but then I'm not sure what nasty tastes might be extracted along with the last litre or so of sweet wort.

it's worth using the efficiency calculator in 'Graham Wheeler's Beer Engine' to check efficiency after the mash and after the boil. If you don't already have GW's BE it can be downloaded from here. It's also really good for creating recipes!

Hope this is helpful.

Guy

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by chris2012 » Tue Apr 23, 2019 10:17 am

That's the strike temp. calculator I used actually. However I wonder if I have a fair loss of heat as I pump from the HLT to mash tun.

I will definitely try and sparge properly next time too.

I'll have a look into 'beer engine' too thanks!

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by guypettigrew » Tue Apr 23, 2019 11:12 am

I set my HLT to 85°C, then pump to the mash tun. After a vigorous stir and running a litre or so of liquor into a jug and pouring it back into the MT the liquor in there is usually close to my desired strike temperature. Usually about 74°C.

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by chris2012 » Tue Apr 23, 2019 11:24 am

Sorry I'm a bit confused, you mash at 74C?

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by Kev888 » Tue Apr 23, 2019 11:57 am

74c is his strike temperature of the mash liquor; so adding the grain will then cool this and if it was calculated correctly the combined total will automatically arrive at the mash temperature.

Probably you know all this but for completeness: most strike temperature calculators are referring to the liquor once stabilised in the MT. They don't account for losses during transfer from HLT to the mash tun, or even the warming of the mash tun itself. So you will need the initial (e.g. HLT) temperature to be higher, especially if the mash tun is heavy stainless or cold. With experience of a given setup you'll be able to gauge how much higher, but if in doubt you might find it easier to overshoot a little and then simply allow the mash liquor to cool to the exact strike temperature. Filling the MT cooler and then trying to warm it up is also valid, but can be more faff, partly as the natural cooling is against you. But in either case, do any adjustments needed to the strike temperature (i.e. 'before' mashing in) and life will be much simpler during the mash.

It is possible to measure the mash tun's thermal capacity and so calculate things more closely. But for most thin/homebrew vessels you can get away with just getting the strike temperature of the mash liquor as the calculator suggests.
Last edited by Kev888 on Tue Apr 23, 2019 12:03 pm, edited 1 time in total.
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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by PeeBee » Tue Apr 23, 2019 12:02 pm

Kev888 wrote:
Tue Apr 23, 2019 9:47 am
If you didn't sparge then that will likely be by far the main reason for getting lower gravity results. …
Ahh, Kev, that's contradicting what I'm trying to push at the moment: No sparge and full boil volume mashes. Does limit SG, at least when using a 30L Grainfather: My last brew (only full-strength brew using this method so far) had an SG 1.055 which was really pushing the volume limits of a Grainfather (I with-held 3L of mash water for boil top-up after the grain basket was removed too). But I'd reduced my expected brew-house efficiency to 72% from 75% and didn't need to; I ended up with 1.055 but was aiming for 1.053/54.

I risked "no sparge" 'cos the BIAB bunch (also using full boil volume mashes) said it doesn't have much effect on efficiency.

But, to steer back on subject, I have found myself using fine grind and with the Grainfather false bottom which is fairly coarse holes. I grind my own grain using a gap of 0.83mm (Bulldog mill) which is tighter than many would consider apparently (I recently dropped it from 0.88mm because of low efficiency) and does appear finer than some 'normal' commercial grinds. But finer grinds might be better for recirculating mash systems? And a Grainfather does drain the mash grain quite well.
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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by guypettigrew » Tue Apr 23, 2019 12:45 pm

chris2012 wrote:
Tue Apr 23, 2019 11:24 am
Sorry I'm a bit confused, you mash at 74C?
As Kev888 says, 74°C is the strike temperature, ie the temperature of the liquor before the grain is added. By the time I've added about 5.5Kg of grain at (say) 15°C the mash temperature is at 66°C.

Andy's strike temperature calculator does all the sums for you!

Guy

Edit-forgot to say, as Kev888 mentioned, the equipment takes a lot of the heat from the liquor. With my set up I've found setting the HLT to 85°C gives me the right temperature in the MT. It may well be different with your set up.

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by chris2012 » Tue Apr 23, 2019 1:08 pm

Oh sorry I got you now, I was confused about the two figures for some reason. This has just given me an idea, since I have a pump on my HLT and Mash tun, I guess I could recirculate the water from HLT to Mash tun, prior to adding the grain, so that there is no drop in temperature while transferring (the mash tun will obviously eventually lose heat though). Then add the grain. And turn off the pumps. (Kind of like RIMS, but not pumping the actual wort, just liquor)

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Re: Maltmiller fine crush, ok for use in a mash tun, with a false bottom?

Post by Kev888 » Tue Apr 23, 2019 1:40 pm

PeeBee wrote:
Tue Apr 23, 2019 12:02 pm
I risked "no sparge" 'cos the BIAB bunch (also using full boil volume mashes) said it doesn't have much effect on efficiency.
Yeah, a couple of things going on there, I guess: If one doesn't sparge, then wort retained by the grain will be at around the full pre-boil gravity, whereas if you do sparge (properly) not only will this have a rinsing effect but the liquid then retained by the grains will be of quite low gravity - and so the grain will retain far fewer of the precious sugars.

However, full-volume BIAB partially mitigates this by the bag being very free draining indeed (essentially a 360 degree false bottom that can be squeezed), so it reduces lost sugars by reducing the retained wort volume instead. Similarly, the bag has no deadspace to lose the high gravity wort there.

Systems like the grainfather are pretty good; their grain drains by gravity and the malt pipes/baskets have no deadspace. A traditional mash tun as used in the OP though will typically retain more wort in the grain and likely have more deadpace (especially if pumped); so at full volume this will be less efficient than a bag, and/or 'much' less efficient than it could be if optimally sparged as intended.
Kev

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