# Direct Heating Mash Tun - Burning



## Screwtop (8/7/07)

Have been directly heating my SS keg type mash tun for a while (5 batches). Using a 3 ring gas burner, usually only use the inner two or the middle ring. During the third mash using this method I detected a burnt mash smell, only slightly. When cleaning afterwards I removed the FB and there was some burnt/caramelised mash burnt onto the bottom under the FB. This carbon was really difficult to remove from the SS, took ages. After mashing today removed the FB again and there was a small amount of burnt mash there again.

A couple of questions for others using this method. 1. Could this be from too thin a bottom in the tun (keg). 2. Could it be from the bottom of the tun being too close to the burner as the centre which is closest to the burner is the worst.

I'm really enjoying the freedom of being able to step mash easily using direct heating, but don't want to be burning the mash. The reason I started direct heating using a gas burner was because I was having trouble with this same problem using a hand held immersion heater.

Screwy


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## mika (8/7/07)

Could be a bit thin on the base for the amount of heat and how fast you want to heat it.
You can try thickening up the bottom, which may well slow the heat transfer rate. I have heard of people using the little ceramic bits and pieces like you use in the column of a :cough: water distiller. The idea is to end up with more surface area over which the heat is transferred. It'd be fun digging them out of the mash at the end of it all and to work properly they'd probably need to be under the false bottom to get the best contact with the bottom of the pot.
Couple of ideas for you.


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## Pumpy (8/7/07)

Screwtop ,

I have been considering direct heat to my mash tun and been looking at Zwickles mash tun which uses a stirrer however I still think he raises the temperature gradually to avoid scorching the grain .so imagine his brewday takes a fair bit longer.

http://www.aussiehomebrewer.com/forum/inde...ic=7364&hl=

Pumpy


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## Tony M (8/7/07)

Direct heating gives great flexibility with temp control and it is dead easy provided you keep the mash stirred. However with a false bottom, I dont see a practical way to keep the material in contact with the tun bottom agitated. It is easy with a perimeter filter. Here is mine.


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## Zwickel (8/7/07)

wow Tony, beautiful work mate :super: 

Screwy, to avoid burning the mash Im using pots with so called "sandwich bottom" thats a bottom made from many layers of metal.
have a look at the bottoms:
http://www.aussiehomebrewer.com/forum/inde...si&img=1055
that kind of bottom spreads the heat equable to the pot.
Also the stirrer is working permanent.

In your case, Id suggest you not to heat up with full power and the use of a permanent stirrer.
Also a kind of chimney (wind shield) would help, like this:





Some homebrewers have mounted a copper chain at theire paddel, it slides over the bottom to avoid burning the mash.

you may think over that.

Cheers


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## sqyre (8/7/07)

hmmmm...

I'm curious, what would happen if you were to continuously circulate using a march pump while mashing?

possibly with a sparge arm or similar, under the lid to help keep the temp.

would a "stuck sparge" be guarranteed to occur from circulating for that amount of time??

That should keep the mash from burning in one spot as well as help to evenly distribute the heat through the mash...



Just a sunday night drunken uneducated thought...

sqyre..


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## Zwickel (8/7/07)

sqyre said:


> hmmmm...
> 
> I'm curious, what would happen if you were to continuously circulate using a march pump while mashing?
> 
> ...


Sqire, thats indeed a good idea, some homebrewer around here had tried that already, but they say the wort has been caramelized at the heating coil.

Another idea comes from a company that sells the "Speidel Braumeister", its a commercial version of a homebrewing system.

They keep the grain in a so called "grain tube" and the wort is pumped permanently through the grain tube and heated outside.

just have a look at it here:
http://www.speidels-braumeister.de/shop_co...sche-daten.html

Cheers :beer:


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## ant (9/7/07)

sqyre said:


> hmmmm...
> 
> I'm curious, what would happen if you were to continuously circulate using a march pump while mashing?
> 
> ...



My understanding is that very idea is the basis of a HERMS system; to continuously recirculate the wort during the mash. From what I've read and seen in action, you are *less* likely to get a stuck sparge because you are getting a nice compact grain bed, and you evenly distribute the heat through the mash.

This idea won't change any burning/scorching of the mash though, because the idea is to continuously circulate the wort, and not the grain. The grain itself will still be sitting on the bottom of the mash tun, so it will still be scorching.

If the idea is to continuously circulate the mash and not just the wort, I think you would be in for a difficult sparge... it would probably be easier to recirculate the wort and add a coil to the HLT (or separate HERMS unit) to avoid the scorching. Wouldn't it??? :huh:


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## blackbock (9/7/07)

I'm glad this thread came up - I was hoping a FB would minimise the problem (currently working with s/s braid only.) Looks like, if anything, a FB makes the problem worse, because you can't stir under it. I have burnt a mash only once, but the taste is impossible to ignore. I noticed when it happened to me, the burnt region was a relatively small area right in the centre. Perhaps spreading the gas flame with a pipeclay triangle or similar may work?

Is there anyone who direct heats their mashtun with a NASA? Hot water infusions may be easier after all!


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## blackbock (9/7/07)

I just had another idea. You could somehow use a water bath to heat the tun, just like chefs do when they melt chocolate. I might mull over this idea.


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## Batz (9/7/07)

ant said:


> My understanding is that very idea is the basis of a HERMS system; to continuously recirculate the wort during the mash. From what I've read and seen in action, you are *less* likely to get a stuck sparge because you are getting a nice compact grain bed, and you evenly distribute the heat through the mash.
> 
> This idea won't change any burning/scorching of the mash though, because the idea is to continuously circulate the wort, and not the grain. The grain itself will still be sitting on the bottom of the mash tun, so it will still be scorching.
> 
> If the idea is to continuously circulate the mash and not just the wort, I think you would be in for a difficult sparge... it would probably be easier to recirculate the wort and add a coil to the HLT (or separate HERMS unit) to avoid the scorching. Wouldn't it??? :huh:




This is what I do ant,the HERMS coil is in a 20lt urn.
The mash is continuously recirculated,I can easly dial up step mashes with this system.I have never had a stuck sparge as yet  ,with a double batch and big beers the flow is slower,this is because of the grain weight crushing the braid rather than a compressed grain bed.





The wort is taken from the mash tun value,pumped via the march pump (mounted under the switch board) then through the HERMS coil and back into the top of the mash tun.

Sorry for the hijack Screwy,not answering you question at all

Batz


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## Screwtop (9/7/07)

Thanks for the replies brewers, all of the suggestions raise further questions, I do stir but as was pointed out you can't move the mash accross the bottom of a tun with a FB. Burning depends upon the mash schedule and type of grain. A mash of straight Pilsener burns a little over a 4 step mash, any mash containing 500gr or more of corn burns even on a single step. Zwickles sandwich base is the answer I think, seems the SS is too thin. Thought of having a thermowell dish welded onto the base of the tun. Maybe it's time for a HERMS like Batz, have a second HLT that I could put a coil into, all I'd need is a pump. Maybe a pottery heatsink under the tun might work. It's not that much of a deal as long as the FB is removed and the carbon scrubbed off after each use. 

Made a fine Zwickel Pilsner yesterday and only had a small area of caramelisation under the FB. Thanks to Zwickel, will post his recipe for a North German Pils (Beersmith 24L batch) later today. 


Does anyone have any suggestions as to what to use to remove the carbon, tried a little caustic solution, but still it was hard to remove, mostly SS scourer and elbow grease is required.

Screwy


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## schubidubi (9/7/07)

I don't know if you like the Idea (it's not mine) but why not lifting the grains of the bottom like this home brewer:
http://www.thebrewingnetwork.com/phpBB2/viewtopic.php?t=4650

Hope I can help instead of asking questions all the time


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## Pumpy (9/7/07)

I could put my immersion heater in a tall narrow SS pot and used one of those MashMate Hot Liquor & Mash Tun Temperature Controller DEI-106 to control the immersion heater then recirculate by pumping the the mash wort through it and back into the Mash tun like Batz, untill the wort was up to temp .


Pumpy :unsure:


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## Tony (9/7/07)

i think thats called a RIMS Pumpy...... cant remember what it stands for.

i have a piccy of a cool invention i was on the net once, i have thought about building one but was worried about de-maturing enzmes by over heating the recirculating wort

Its just a piece of copper tube with a 2400W element jamed up the middle

probably not on subject but close

cheers


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## tangent (9/7/07)

re-circulating (something starting with i) mash system


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## BenH (9/7/07)

Screwtop (and others who directly heat their mashtun),

Do you insulate your mashtun?

I have a SS keg that is wrapped in a camping mat, but still find I lose an unacceptable amount of temp over a 60min mash. 

I'm considering directly heating the mash tun but don't want to melt/burn the 'insulation'. (I have a copper manifold so will be able to stir the mash). On the other hand, I don't want to have to stand there and stir for 60 minutes, so would like to just bump up the temperature every now and then.

Cheers, BenH.


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## Tseay (9/7/07)

Has anyone tried heating the mash using a hot water version of a chilling coil. Presumably you would have to add hot water initially. Would it just be too slow ?


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## Screwtop (9/7/07)

BenH said:


> Screwtop (and others who directly heat their mashtun),
> 
> Do you insulate your mashtun?
> 
> ...




My SS mash tun is insulated with a camping mat style rubber and a windshield insulation screen, heating gently using the inner two rings of a three ring burner is not a problem, tried using the outer ring but heat came up through the holes in the lower chime and the insulation got a bit sticky and smelly.

Good explanation of RIMS and HERMS HERE

Screwy


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## Tony M (9/7/07)

BenH said:


> Do you insulate your mashtun?
> I have a SS keg that is wrapped in a camping mat, but still find I lose an unacceptable amount of temp over a 60min mash.
> I'm considering directly heating the mash tun but don't want to melt/burn the 'insulation'. (I have a copper manifold so will be able to stir the mash). On the other hand, I don't want to have to stand there and stir for 60 minutes, so would like to just bump up the temperature every now and then.
> 
> Cheers, BenH.



I have 25mm of rockwool or fibreglass around mine. It doesnt mind the heat. I hit the empty pot for 30 or 40 seconds to warm it a little before I add the grain and water otherwise the mash temp drops a couple of degrees in the first five minutes as the SS tun slowly warms up. One more hit of two or three minutes about half way thru the mash is all the extra heating reqd. before mashout which is also quick and easy with two rings burning.


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## Dr Gonzo (9/7/07)

Tony,
Nice looking paddle.
What do you use to drive it?


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## sqyre (9/7/07)

ant said:


> This idea won't change any burning/scorching of the mash though, because the idea is to continuously circulate the wort, and not the grain. The grain itself will still be sitting on the bottom of the mash tun, so it will still be scorching.



True... 

but i was thinking along the lines of the mash tun having a false bottom suspending the grain above the direct heating surface with only the circulating wort coming in contact with the base.

The only issue i can think of is the tiny particles that pass through the false bottom and sit on the bottom of the tun. Perhaps a BIAB style bag could be used as a filter/liner to reduce this.



sqyre.. :blink:


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## Screwtop (9/7/07)

sqyre said:


> Perhaps a BIAB style bag could be used as a filter/liner to reduce this.
> 
> 
> 
> sqyre.. :blink:




Might be onto something there Brucey, will try this as a first fix, Plan B: have a stainless dish made up to go on the burner under the tun, fill this with water to act as a bain maree. Will need to get one made out of SS sheet about 2mm thick, 400mm diam, side wall 120mm with base welded in leaving a 20mm collar below to contain the burner lames. Ie: the dish would be 98mm deep and the tun would sit in that. Have to find a fabricator.

Screwy


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## sqyre (9/7/07)

If the bottom of your tun is flat, i would firstly try putting a piece of 3-4mm steel plate between the burner and the tun... this should act as a dampener to help disperse the heat evenly. if it makes even contact with the tun bottom it should transfer the heat and not act as heat shield..

bit like a pot on a barbie plate... 

That would stop any "hot spots" from from occuring..although it will take a little longer to heat up untill the plate is hot then it should be business as usual..

if it doesnt work just slide the plate out...

worth a try... :huh: 

i would use some mild steel plate, stainless may be more likely to act as a heat shield with its shiny surface. Just a thought..

Sqyre...


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## mika (9/7/07)

Draggin it OT again, I've thought a mini external cylinder for HERMS operation would be a good thing. Something small allowing rapid control of the Heat Exchanger temperature, as Pumpy suggested with an electric element, Mashmate temp controller for easy control without going full P&ID loop control.
I haven't come across an element small enough with enough grunt.


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## Screwtop (9/7/07)

sqyre said:


> If the bottom of your tun is flat, i would firstly try putting a piece of 3-4mm steel plate between the burner and the tun... this should act as a dampener to help disperse the heat evenly. if it makes even contact with the tun bottom it should transfer the heat and not act as heat shield..
> 
> bit like a pot on a barbie plate...
> 
> ...



Nah Bruce,

Mash tun has a Keg Style bottom!


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## ant (10/7/07)

Screwtop said:


> Plan B: have a stainless dish made up to go on the burner under the tun, fill this with water to act as a bain maree. Will need to get one made out of SS sheet about 2mm thick, 400mm diam, side wall 120mm with base welded in leaving a 20mm collar below to contain the burner lames. Ie: the dish would be 98mm deep and the tun would sit in that. Have to find a fabricator.
> 
> Screwy



A 20L urn with a copper coil in it sounds cheaper in the long run - and easier for precise temp control? h34r:


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## Tony M (10/7/07)

Dr Gonzo said:


> Tony,
> Nice looking paddle.
> What do you use to drive it?


A BBQ spit motor. Its a bit slow for my liking as I can hear the mash starting to simmer when it has been heating for a while. I am about to change this as the controller for our garage door got fried in a storm the other night so I am having to fork out for a retro fitted motor/controller combination. The upside of that being I will be left with a beaut little geared 24V motor. Not bad for $500.00!!!!


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## Screwtop (26/7/07)

ant said:


> A 20L urn with a copper coil in it sounds cheaper in the long run - and easier for precise temp control? h34r:




Well the dish idea didn't work, scrounged a big SS tub from the tip shop and cut the bottom out, too much energy loss, too slow. Got the shites with the Immersion Heater and attacked it opening up the coils gently using a F/big screwdriver. Now it works a treat! the mash doesn't get lodged in the thing and burn.

Have a 45L urn, got it for a song as it was not working, shouted it a new simmerstat for $23, works well now. Think a HERMS might be the GO, off to the scrap yard for a copper coil from inside an old hot water system. Next a Pump!

ED: Splng


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## rehnton (26/7/07)

talking scorching does anyone have a magical cure for cleaning burnt on wort from over the side style immersion element?
mine's rogered; was hoping to revive it sufficiently to use in the HLT
tried CLR, elbow grease, even soaked overnight in coke but cant get the inside or between coils clean


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## Darren (26/7/07)

rehnton said:


> talking scorching does anyone have a magical cure for cleaning burnt on wort from over the side style immersion element?
> mine's rogered; was hoping to revive it sufficiently to use in the HLT
> tried CLR, elbow grease, even soaked overnight in coke but cant get the inside or between coils clean





Try hot napisan for a couple of hours.

cheers

Darren


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## PostModern (26/7/07)

Darren said:


> Try hot napisan for a couple of hours.
> 
> cheers
> 
> Darren



Failing that, try caustic. Nasty stuff, tho so be careful with use, handling, discarding and ingestion by pets, children, etc.


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## Screwtop (26/7/07)

Haven't tried the hot Napisan but have tried everything else, mild Vinegar to Heavy Caustic. Phosphoric Acid works reasonably well and wont hurt the metal. Go to Bunnings and get a small copper wire brush, a bit like a toothbrush, that and elbow grease works. I spread the coils which seems to stop a lot of that happening the mash doesn't get stuck in between the coils.


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## Batz (26/7/07)

Screwtop said:


> Have a 45L urn, got it for a song as it was not working, shouted it a new simmerstat for $23, works well now. Think a HERMS might be the GO, off to the scrap yard for a copper coil from inside an old hot water system. Next a Pump!
> 
> ED: Splng




Mines a 20lt urn Screwy,but you can see how I did it.
I am really happy with the results,more so since I added a Mashmaster controller to it.






I don't have my system hard plumbed,I like the idea of removing the hoses for a good clean/sanitize.





Batz


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## Darren (26/7/07)

I ahve always wanted to do that Batz, It raises temps ok?

I have the urn and copper but was sceptical it would work.

cheers

Darren


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## Batz (26/7/07)

It takes a few minutes to rise in temperture Darren,10C would take 5 minutes or perhaps a bit more.
After a while you learn to factor that in,I wonder if I should had some more coils into the centre of the urn?
I may give it a go soon I have all the gear here I need.

Batz


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## deckedoutdaz (26/7/07)

Don't let the missus hear i know even the slightest thing about home duties........for cleaning baked on wort and grains.....dip the element into vinegar then liberally cover in bi-carb, it will fizzle and froth, rub off after a couple of minutes with a plastic scourer, if its really baked on you might need to repeat, i believe its the same for cleaning an oven but don't try it or you'll have the job forever.....


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## AndrewQLD (26/7/07)

Batz said:


> It takes a few minutes to rise in temperture Darren,10C would take 5 minutes or perhaps a bit more.
> After a while you learn to factor that in,I wonder if I should had some more coils into the centre of the urn?
> I may give it a go soon I have all the gear here I need.
> 
> Batz



Batz,
I have been looking at going this way, I still have the S/S pot you gave me predrilled for a herms, how about we organise a weekend and you can show me how to build it :lol: . Got a price on 5 mtrs 3/8" copper pipe $53.00 just got to get my head around tooling it up. I've got a keg of heffe we could share as well  .

Cheers
Andrew


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## Screwtop (26/7/07)

Batz said:


> Mines a 20lt urn Screwy,but you can see how I did it.
> I am really happy with the results,more so since I added a Mashmaster controller to it.
> 
> View attachment 13944
> ...



Yeah flexibility is what I want too, will use hoses and probably some brass snap on hose fittings, Bunnings sell one type that seals well, the others are crap. Since it's a big urn I was thinking of making a drop in coil like a chiller, do you think that would work Batz? Or would I need to have the lid on for efficiency. Using the mashmaster do you set the temp of the urn and then recirc to raise the temp to that of the urn (would be a bit lower depending on losses, I guess).

3/4 copper would give more surface area Andrew, was going to use 1/2 in from the scrap yard here.


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## Batz (26/7/07)

Screwtop said:


> Yeah flexibility is what I want too, will use hoses and probably some brass snap on hose fittings, Bunnings sell one type that seals well, the others are crap. Since it's a big urn I was thinking of making a drop in coil like a chiller, do you think that would work Batz? Or would I need to have the lid on for efficiency. Using the mashmaster do you set the temp of the urn and then recirc to raise the temp to that of the urn (would be a bit lower depending on losses, I guess).
> 
> 3/4 copper would give more surface area Andrew, was going to use 1/2 in from the scrap yard here.



You could drill the lid I suppose,you need to keep the coil just off the element as well.
I'll go 1/2" tubing for ease of bending and finding fittings.

Andrew
Easy to finish off the project mate,you need a kettle element,few metres of 1/2" copper tube,rest of the gear I may have floating about.Lets get together for a beer and knock it up hey?



Batz


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## Batz (27/7/07)

Screwtop said:


> Using the mashmaster do you set the temp of the urn and then recirc to raise the temp to that of the urn (would be a bit lower depending on losses, I guess).




Spot on how I do it Screwy,if you use a drop in coil you will be left with it full of wort after recirc.


Batz


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## Screwtop (27/7/07)

Batz said:


> You could drill the lid I suppose,you need to keep the coil just off the element as well.
> I'll go 1/2" tubing for ease of bending and finding fittings.
> 
> Andrew
> ...



Thanks Batz, in the bigger urn the coil can be wound to sit outside the element, I think that would work? 1/2 inch is easy to source from scrap. 

Andrew, for urn bits at reasonable prices try J G Thomas in Bayswater WA. The usual suppliers told me there were no spares available for my old Langco. J G Thomas had replacement parts, new simmerstat only $23.90 

Screwy


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## Screwtop (27/7/07)

Batz said:


> Spot on how I do it Screwy,if you use a drop in coil you will be left with it full of wort after recirc.
> Batz




The plumbed in coil would still have wort left in it too, but not as much I guess. Might plumb it in! Do you use the snap on hose connectors?


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## AndrewQLD (27/7/07)

Screwtop said:


> The plumbed in coil would still have wort left in it too, but not as much I guess. Might plumb it in! Do you use the snap on hose connectors?



I plan on having my HLT sparge water run through the herms coil at the end of the recirculation, seems it would be a good way to clean it, is this how you have yours setup batz?

Screwtop, I plan to use a smallish S/S pot for the herms with an elcheapo BigW kettle element. I figure if I keep the volume of water in the herms as small as possible then the heating cycle should be more predictable. Some good info here

Cheers
Andrew


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## Batz (27/7/07)

Screwtop said:


> The plumbed in coil would still have wort left in it too, but not as much I guess. Might plumb it in! Do you use the snap on hose connectors?




Gravity is my friend as far as wort left in the coil.
I use those plastic wing nut type connectors you can buy from boating places.





They come in straight or 90,and screw straight on to 1/2" bsp nipples.Also have 1/2" barb for the hose.

$5.95 each

Batz


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## Screwtop (27/7/07)

Andrew, interesting stuff, as recommended use a small vessel for the heat exchanger. That was why I'd considered using the drop in coil in the 45L urn. Thought it might be better off being preserved for use as something else, maybe HLT or something in the future once I can get a hold of a smaller urn.

Have some of those hose nut and tails Batz, thought the barb might crack off too easily being plastic so was going to try the snap on type.


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