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Direct Heated Mash Tun

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chiller

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At 4.00 am one morning I woke with a start. A direct heated mash tun, why not.

I needed a vessel to convert -- existing 50 litre aluminium HLT.

A manifold to fit -- the one from my 38 litre rubbermaid was exactly right.

A source of heat -- now for a very brief moment I considered another jet burner [nasa :)] but the idea of scrapping a scorched mesh out of the tun didn't appeal.

I visited all things hot -- globe imports and they had this minute single ring burner that looked as if it would do.

Insulation for the tun [not while flame is on]. A cheap camping mattress from clarke rubber and I was ready.

I estimated the small burner would raise the tun 1 degree per minute and it did so the temperature increase wasn't too rapid.

Despite the fact most grains now are fully modified I have always tried to do a rest at 50, 60, 70 and 75C but with hot water additiuons you run out of tun very quickly.

My first step was spoton 50C which I held for 10 minutes and then applied heat to raise the temperature to 60C. This took 10 mionutes and during each temperature increase I gently moved the mash to prevent any scorching. The next rest at 60 C was held for 30 Minutes and even though the tun is Aluminium and only had a rubber camp matteress for insulation the temperature didn't change at all in the 30 minutes.

The next step was 70C and again this took 10 minutes to reach temperature. and was held for 30 minutes as well.

I usually don't worry about a mash out but with direct heat it was a breeze. 75C for 10 minutes and then start the sparge.

The runoff was very clean and my efficiency is up by about 4% using my normal batch sparge.

My biggest concern was burning the mash but with a small gas flame and the Aluminium pot for heat distribution I didn't have any problems.

I use Sodium Met in my mash so the extra movement of the mash won't cause any problems.

As an aside the extra efficiency is probably due to the stirring of the mash as the temperature is raised.

Steve
 

Doc

Doctor's Orders Brewing
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Awesome.
Got pics ?

When is the next 4am brainwave ?

Beers,
Doc
 

GMK

BrewInn Barossa:~ Home to GMKenterprises ~
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excellent idea Chiller...

Things like "Some people need to get a life" come to mind - But i think in your case it is more like "Some people need to goto sleep"...

:lol:

i like the rubber camp mattresses - i insulate my aluminium kettle with one.

Note:
Best thing about using Aluminium is you can have the same brilliant new idea, tommorow, and the next day , and the next day and so on...

:D
 

Justin

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Yep, there are no problems with direct heating the mash. A number of my friends do it this way with uninsulated converted keg mash tuns. If you don't get too carried away with the speed of heat application and make sure you stir then it all works flawlesly. If you stop stirring you "will" scorch. My friends have been using manifold designs over false bottom so I'm not sure how a false bottom would go, still assuming no problems though.

One reason that some people go to a herms or rims set up, is after stirring a thick mash for 10+ minutes that might be 10gallons in volume, it feels like your arms are going to drop off.

Don't stop stirring and all should go well.

Cheers, Justin
 

Darren

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Steve,
Don't leave that mash for a minute. If the dog escapes, phone rings, misses calls turn the burner off. Only takes a second to scorch and you will probably find out until the brew-day is finished and its time to clean up.
Then you will need to get a taste for smoked beer

Cheers
Darren
 

Snow

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Sounds great, Chiller. I used to do a similar thing with my partial mashes in my 10L boil pot, before I moved to an esky. Worked well every time.

As an aside, why do you add Sodium Met to your mash? I've heard of others doing this, but I never really worked out why.

- Snow
 

Hoops

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When I was in one of the Brisbane Brew clubs there was a guy in the club who step mashed by directly heating the mash tun......with steam.
He had a pressure cooker heated by a gas burner, hooked up to some tube going into the manifold in the mash tun with a valve. When he wanted to heat the mash he turned the burner on full bore, opened the valve up which sent the steam through the manifold. You still have to stir it or you get areas of differing temperature. He was very happy with it as it didn't burn the grain as it could only heat it to a maximum of 100C.

Something that I would like to get around to doing in the future. I would go Electric element in a sealed boiler (with pressure relief valve), into the mash tun with a motor to mix the grain. Would love to set it all up so it's controlled by computer and semi-automatic.
Well I have to have something to aim for :rolleyes:

Hoops
 

Kai

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Snow, my understanding is that sod met acts as an antioxidant, ie it gets oxidised in place of those precious compounds in your mash, minimising any risk of HSA and helping keep the colour slightly lighter in light coloured beers.

Same principle as dried apricots.

Awesome.
Got pics ?

When is the next 4am brainwave ?

4am?
 

chiller

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Hi guys just an update on the heated mash tun.

I've put a jet [nasa] burner under the tun and it is very controllable.

Just brewing a stout with oats so a protien rest was in order. And then stepped to 65 then 70 then to 75.

Very easy and as long as the temp is kept at 1c per minute all should be well.

The real answer is the Aluminium pot as the heat distribution is awesom.

Steve.

PS pics to come. :)
 

ausdb

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I am in the process of looking at ways to improve my brewing setup and trying to decide between staying with an esky/indirect heated mash tun and going to a direct fired system or a herms/rims. As I like german styled beers stepped mashes are part of the fun.

Is the 1C a minute a hard and fast rule as far as the amount of heat you can safely add without scorching? I remember a thread or something somewhere basically poo-pooing direct heated mashes and herms/rims systems as they were saying the step times took too long and the only real way to do stepped mashes was either with boiling water infusions or decoctions.

I have played around with direct steam infused step mashes which seem to work well for a 20-25l batch size but take too long for the steps with a 40L batch size, I need more steam heating capacity. I could also use the pressure cooker to do a decoction but havent tried it.

Hopefully this will start a bit more of a discussion about the relative merits of each system

Cheers ausdb
 

Darren

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Hopefully this will start a bit more of a discussion about the relative merits of each system

Cheers ausdb
[post="64312"][/post]​
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ausdb,
My only advice with bottom heating is that you need to be very careful not to scorch any grains sitting on the bottom of the tun. It is not the sort of method you can use if you want to walk away even for a second. Also, constant recirculating does not prevent scorching
A rims or similar would get my vote for step mashing
 

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