### Author Topic: Help with direct heating mash tun  (Read 3430 times)

#### charlie

• Assistant Brewer
• Posts: 225
##### Re: Help with direct heating mash tun
« Reply #15 on: February 22, 2019, 08:19:06 pm »
In operationg a lauter tun, the metric that matters is not flow rate, but velocity -- not gallons per minute, but inches per minute  -- in order to establish the ...

Meh. I'm too lazy to do the math, and one GPM works for me. ;-)

Charlie
Yes officer, I know that I smell like beer. I'm not drinking it, I'm wearing it!

#### Robert

• Official Poobah of No Life. (I Got Ban Hammered by Drew)
• Posts: 4214
##### Re: Help with direct heating mash tun
« Reply #16 on: February 22, 2019, 08:41:33 pm »
In operationg a lauter tun, the metric that matters is not flow rate, but velocity -- not gallons per minute, but inches per minute  -- in order to establish the ...

Meh. I'm too lazy to do the math, and one GPM works for me. ;-)

Charlie
I, too, established my flow rate (I use a lauter tun) by long time experience teaching me what works.   Then I ran all the calculations from the article and found out... I was dead nuts on the perfect velocity.  So that kind of proves (in a bass ackwards way) the validity of the formulas and theories, which means if somebody's having trouble, they should get them to a solution faster than trial and error.  But yeah, Charlie, those of us who lucked into it really don't need to hurt our brains with extra math!
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.

#### BrewBama

• Official Poobah of No Life. (I Got Ban Hammered by Drew)
• Posts: 6130
##### Help with direct heating mash tun
« Reply #17 on: February 23, 2019, 07:12:53 am »
One name for the aluminized bubble insulation is Reflectix.

Will direct heat affect the bubble insulation? I think I've heard that on other threads.

If direct heat means an open flame source — yes it will melt and even possibly ignite. Either way it’s gonna smell like @\$\$. If direct heat means electric coil — less of a problem (don’t let it touch).  Induction — no problem.

FWIW — my recirculating mash combination sweet spot is 5/16” on a pump output linear flow control valve (which is ~.7 gpm), a 1.75 qt/lb mash thickness, and a course crush where the kernels are broken into grits vs flour (.040 at the center of a JSP two roller mill).

I found it interesting that Mecca Grade recommendation for their malt is to “achieve the best possible extract and flavor, please consider using at least a .040” mill setting to maintain a fine crush on our malt.

No whole kernels

All kernels broken into at least three pieces

Starch exposure is critical”

Sent from my iPad using Tapatalk
« Last Edit: February 23, 2019, 08:35:38 am by BrewBama »

#### Mr SOnSO

• 1st Kit
• Posts: 15
##### Re: Help with direct heating mash tun
« Reply #18 on: February 23, 2019, 12:07:12 pm »

If direct heat means an open flame source — yes it will melt and even possibly ignite. Either way it’s gonna smell like @\$\$. If direct heat means electric coil — less of a problem (don’t let it touch).  Induction — no problem.

FWIW — my recirculating mash combination sweet spot is 5/16” on a pump output linear flow control valve (which is ~.7 gpm), a 1.75 qt/lb mash thickness, and a course crush where the kernels are broken into grits vs flour (.040 at the center of a JSP two roller mill).

I found it interesting that Mecca Grade recommendation for their malt is to “achieve the best possible extract and flavor, please consider using at least a .040” mill setting to maintain a fine crush on our malt.

No whole kernels

All kernels broken into at least three pieces

Starch exposure is critical”

Sent from my iPad using Tapatalk

I appreciate all the input on this subject.
It is open flame direct heat so any insulation will have to contend with that. In previous brews I have used a slower flow (not sure of the rate) with less than great results. Either the heat loss through the hoses, pumps and mash tun does not raise temps or the wort temp rises (190s +) under the false bottom and boils the wort which really restricts flow.

As I said in the original post, ambient temp has been around 50 in my garage and even when doing a single mash no recirc my temps are falling 8 degrees in a 60 minute mash. Thats with covering the lid of the tun with a blanket and covering the entire mash tun past the bottom with a flannel lined sleeping bag. The weird thing is, I used to use this method when I lived in Wisconsin and wouldn’t lose more than 4 degrees during winter months. And thats with removing everything and stirring the mash every 15 minutes.

I did increase the coarseness of my grind just a bit to improve flow but did not lose efficiency which is at 75%.

BTW how do you measure crush on your mill? I use a 2 roller Monster Mill.

#### Robert

• Official Poobah of No Life. (I Got Ban Hammered by Drew)
• Posts: 4214
##### Re: Help with direct heating mash tun
« Reply #19 on: February 23, 2019, 01:05:16 pm »
Measure the gap on your mill using feeler gauges from the auto parts store, about \$6 for a set.  I have the MM2 Pro with the 2" rollers and set it to 0.032" with good results, but that means little as you need to optimize the crush for your rig.

If you're having heat loss in the hoses, you could try wrapping them with foam pipe insulation.
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.

#### BrewBama

• Official Poobah of No Life. (I Got Ban Hammered by Drew)
• Posts: 6130
##### Help with direct heating mash tun
« Reply #20 on: February 23, 2019, 01:06:49 pm »

BTW how do you measure crush on your mill? I use a 2 roller Monster Mill.

I measure crush by looking at the grain kernels to see that each one is broken but not ground to flour. Thru trial and error I found this works for me and my system and how I operate it. Once I was happy I noted the gap measured with a bazillion yr old feeler gauge in the center of the rollers. The match marks were put there by Mr Schmidling as a reference.

Sent from my iPad using Tapatalk
« Last Edit: February 23, 2019, 01:12:06 pm by BrewBama »

#### Mr SOnSO

• 1st Kit
• Posts: 15
##### Re: Help with direct heating mash tun
« Reply #21 on: February 23, 2019, 01:19:50 pm »
Measure the gap on your mill using feeler gauges from the auto parts store, about \$6 for a set.  I have the MM2 Pro with the 2" rollers and set it to 0.032" with good results, but that means little as you need to optimize the crush for your rig.

If you're having heat loss in the hoses, you could try wrapping them with foam pipe insulation.

BTW how do you measure crush on your mill? I use a 2 roller Monster Mill.

I measure crush by looking at the grain kernels to see that each one is broken but not ground to flour. Thru trial and error I found this works for me and my system and how I operate it. Once I was happy I noted the gap measured with a bazillion yr old feeler gauge in the center of the rollers. The match marks were put there by Mr Schmidling as a reference.

Sent from my iPad using Tapatalk
Thanks fellas!
I remember hearing years ago on the Brewing Network from someone, maybe Denny, that he crushes until he's nervous. I've followed that instruction ever since.

#### BrewBama

• Official Poobah of No Life. (I Got Ban Hammered by Drew)
• Posts: 6130
##### Re: Help with direct heating mash tun
« Reply #22 on: February 23, 2019, 01:57:58 pm »
When I mashed with a single infusion, I’d tighten the mill as far as it would go which followed Denny’s advice. In fact, I started all grain brewing patterned on his setup.  A guy named Don Osborn does videos on Youtube using his method which is how I learned to brew. It made getting into all grain very approachable.

But now, I use a Recirculating Infusion Mash System and perform Hochkurz-style steps. That fine a crush with a thicker qt/lb ratio mash thickness would compact the grainbed, I’d get poor extract and often frustrating brew days due to a cavitated pump.  So, I began making adjustments for my system and how I operate it.

I ended up with a ~.7 gpm flow rate, a .040 mill setting, and a 1.75 qts/lb mash thickness as my combination sweet spot. I’ve thought I might mash thinner but I am happy with my results at this point.

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#### Bilsch

• Assistant Brewer
• Posts: 249
##### Re: Help with direct heating mash tun
« Reply #23 on: February 23, 2019, 08:33:09 pm »
Another good way to measure you gap is to use post it notes. You take a small stack, just guess at an amount then remove sheet by sheet and measure after each sheet with a micrometer or vernier caliper until you get the thickness you looking for. Then feed this stack into the mill gap and tighten the adjustment until the stack just goes in with a slight resistance.

#### goose

• Senior Brewmaster
• Posts: 1299
##### Re: Help with direct heating mash tun
« Reply #24 on: February 24, 2019, 07:46:25 am »

If direct heat means an open flame source — yes it will melt and even possibly ignite. Either way it’s gonna smell like @\$\$. If direct heat means electric coil — less of a problem (don’t let it touch).  Induction — no problem.

FWIW — my recirculating mash combination sweet spot is 5/16” on a pump output linear flow control valve (which is ~.7 gpm), a 1.75 qt/lb mash thickness, and a course crush where the kernels are broken into grits vs flour (.040 at the center of a JSP two roller mill).

I found it interesting that Mecca Grade recommendation for their malt is to “achieve the best possible extract and flavor, please consider using at least a .040” mill setting to maintain a fine crush on our malt.

No whole kernels

All kernels broken into at least three pieces

Starch exposure is critical”

Sent from my iPad using Tapatalk

I appreciate all the input on this subject.
It is open flame direct heat so any insulation will have to contend with that. In previous brews I have used a slower flow (not sure of the rate) with less than great results. Either the heat loss through the hoses, pumps and mash tun does not raise temps or the wort temp rises (190s +) under the false bottom and boils the wort which really restricts flow.

As I said in the original post, ambient temp has been around 50 in my garage and even when doing a single mash no recirc my temps are falling 8 degrees in a 60 minute mash. Thats with covering the lid of the tun with a blanket and covering the entire mash tun past the bottom with a flannel lined sleeping bag. The weird thing is, I used to use this method when I lived in Wisconsin and wouldn’t lose more than 4 degrees during winter months. And thats with removing everything and stirring the mash every 15 minutes.

I did increase the coarseness of my grind just a bit to improve flow but did not lose efficiency which is at 75%.

BTW how do you measure crush on your mill? I use a 2 roller Monster Mill.

Additional information regarding insulation on the keggle mash tun. Only insulate the keggle between the top and bottom "rims" where they are welded to the keggle.  Also leave the draining holes where the rim meets the top and bottom of the keg uncovered. This will reduce the possibility of melting the insulating material with a normal flame from the burner.  Using the duct insulation I mentioned previously, I have never melted the spongy backing with direct heat in the 20+ years I have been using this material.  If you want to make a nice finish at the top and bottom of the insulating layers on the keg, you can use some aluminum tape to do so, also available at a big box store like Lowes.  This will also keep things like water and spilled grain particles from getting in between the insulation and the keggle.

I would post pictures here but I am out of town and unable to do so.
Goose Steingass
Wooster, OH
Society of Akron Area Zymurgists (SAAZ)
Wayne County Brew Club
Mansfield Brew Club
BJCP Certified

#### denny

• Retired with too much time on my hands
• Posts: 27237
• Noti OR [1991.4, 287.6deg] AR
##### Re: Help with direct heating mash tun
« Reply #25 on: February 24, 2019, 08:24:03 am »
Measure the gap on your mill using feeler gauges from the auto parts store, about \$6 for a set.  I have the MM2 Pro with the 2" rollers and set it to 0.032" with good results, but that means little as you need to optimize the crush for your rig.

If you're having heat loss in the hoses, you could try wrapping them with foam pipe insulation.

BTW how do you measure crush on your mill? I use a 2 roller Monster Mill.

I measure crush by looking at the grain kernels to see that each one is broken but not ground to flour. Thru trial and error I found this works for me and my system and how I operate it. Once I was happy I noted the gap measured with a bazillion yr old feeler gauge in the center of the rollers. The match marks were put there by Mr Schmidling as a reference.

Sent from my iPad using Tapatalk
Thanks fellas!
I remember hearing years ago on the Brewing Network from someone, maybe Denny, that he crushes until he's nervous. I've followed that instruction ever since.

Crush til you're scared
Life begins at 60.....1.060, that is!

www.dennybrew.com

The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts." - Bertrand Russell

#### Mr SOnSO

• 1st Kit
• Posts: 15
##### Re: Help with direct heating mash tun
« Reply #26 on: February 24, 2019, 11:32:08 am »

#### Bilsch

• Assistant Brewer
• Posts: 249
##### Re: Help with direct heating mash tun
« Reply #27 on: March 24, 2019, 09:03:29 pm »
I use meta-aramid (nomex) felt as a high temp fireproof insulation on mashtuns and boil kettles. You can get a 1/4" thick 12"x72" piece for \$28 from the felt store on Amazon.