Stainless Steel or Copper HERMS Coil

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dozer4412

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I want to make a HERMS coil and am looking for some advice. The idea being I’d create an Immersion Chiller and rather than pull it in and out each time I need it I’d attach it inside a Keggle with an input and output bored through the Keg wall and some kind of quick disconnects on the input and output. To start with I’d just use this Keggle as my Brew Kettle and pump cold water to cool, but at some point in the future I’d make this my HLT and use it both to control the mash temp and as a giant ice bath to cool the wort. I’m a long way from the second phase, but why not plan ahead a little.

1.
Should I go with stainless steel or copper for the coil?

a.
The Big Daddy Immersion Chiller thread spells out how I’d go about creating a copper one.

b.
If I went stainless steel I’d use McMaster #8989k98 as suggested by Boerderij.

2.
With stainless how would I go about attaching fittings to the tubing? Copper seems straight forward as I can solder, but I’m no wielder and would like to avoid wielding if possible.

3.
If I use copper should I be worried about the outside of the pipes oxidizing?

It seems like the easy choice is copper, but there’s just something sexy about stainless. I’m still keeping an open mind about what way to go.
 
Copper is cheaper and has better heat transfer properties. I wouldn't worry about the copper oxidizing any more than you would with an immersion chiller, which is usually none at all for most people.
 
I am sure you know my point of view:D

The conductivity of copper vs. stainless is almost completely negligible in our situation. SS will add maybe a minute to your cooling time and zero in my anecdotal experience.

CIMG2816.JPG


CIMG2820.JPG


Built in Stainless Coil $128.27
1 -> Type 304 Stainless Steel Welded Tubing 1/2" OD, 50' Coil $70.33 McMaster-Carr 8989K98 http://www.mcmaster.com/
2 -> 1/2" tube -1/2" FPT Compression fitting (90 deg elbow) SS-810-8-8 $40.00 McMaster-Carr 5943K216 http://www.mcmaster.com/
2 -> 1/2" close nipple $3.44 Buy Fittings Online 27-4P1-1/8 http://www.buyfittingsonline.com/Fittings/item6592.htm
2 -> 1/2" Stainless Steel Washer $5.00 Bargain Fittings - http://www.greatbargain.net/order/shop2.html
2 -> 1/2" Stainless Steel Locknut $9.00 Bargain Fittings - http://www.greatbargain.net/order/shop2.html
2 -> 1/2" Silicon O-ring size 211 $0.50 Bargain Fittings - http://www.greatbargain.net/order/shop2.html

..................

Find the swagelok fittings on eBay by searching for "SS-810-8-8" or by searching "swagelok" and sifting through the listings.

This will give you a 1/2" NPT male nipple exposed outside the keg, from there you can connect it to your system however you see fit.
 
The reason why I'd go SS on a HERMS coil is that you really don't want to remove the thing for cleaning. Copper is going to sit through many cycles of being wet/dry and it will get tarnished. For a wort chiller, the act of using it in acidic wort keeps it clean. I also would suggest having the lower end of the coil penatrate the HLT wall at the bottom instead of running it like an IC because it will allow complete draining.

You can get threads on the tubing with a compression fitting. I wouldn't pay Mcmaster prices though. Watch Ebay for a pair of them.
 
Check on ebay. There is a guy that sells a SS coil there all the time. I got mine for around $60-80 or so, 50' 3/8" coil.

If you buy on eBay you should wait for a better deal IMO. I bought my 1/2" 50' coil on eBay for $30 shipped. I have not seen such a deal since though. $71 new from McMaster for 50' of 1/2" is impossible to beat consistently as far as I have been able to find.

:EDIT: That is a great deal for an immersion chiller! I would still be happier with 1/2" for a HERMS coil.
 
On that point, I went with the thinner 3/8" instead of the 1/2" because with a thinner tube you'd get better warming essentially more of the liquid is touching or near the surface (or that was my thinking). I never did the thermodynamic/heat transfer calculations on it though. LOL

Additionally, I wanted to make my pump push less liquid so as to not stress it (I wasn't sure how good it would work).
 
In your case, 3/8" may be more efficient but will have less cooling potential. Surface area is directly related to heat transfer, and 3/8" to 1/2" makes a pretty significant difference.
 
Thanks for the info everyone. Boerderij that was above and beyond what I was looking for, but I can’t thank you enough for the detailed info.

As I’m new to a lot of this stuff I thought I’d also post the following about Swagelok fittings as I’ve been trying to figure out for the past few days how I’d attach a fitting to the end of my stainless steel tubing. After the video all this talk about Swagelok fittings I keep reading about all made sense.



I’m from the Madison area of Wisconsin.
 
Last edited by a moderator:
Well next time your in Madison let me know and I'll buy you one. The more I get into the sub culture of home brewing the more I realize how great the people involved in it are.
 
I'd love to see some pics when you guys are done. When I first brought up this idea here, it got a lot of criticism (not a bad thing) and people were very skeptical if it would work and be easy enough to clean. A few more supporters and proven systems in public would be great! Cheers, Justin
 
I'd love to see some pics when you guys are done. When I first brought up this idea here, it got a lot of criticism (not a bad thing) and people were very skeptical if it would work and be easy enough to clean. A few more supporters and proven systems in public would be great! Cheers, Justin


Why is cleaning a big concern? It's in the boil kettle.
 
What are people using to bend the stainless steel tubing to create the coil? Will a simple spring tube bender do the trick?
 
Resurrected...

I am planning out a 2 vessle build that would use a stainless steel coil. The HLT would double as the BK and thus the HERMS would be the Chiller as well. I've got a few questions thought.

Would this be difficult to clean given that both the inside and outside of the coil will touch wort? How should I terminate the ends of the coil so that it can be removed or will it be easy enough to clean that I wont need to remove it?

Since its both herms and chiller, what length should I use? Does 50' fit easily inside a Sanke Keggle? What diameter should I make the coil?

Thanks!
 
I've been using and pond pump in a bucket with star-san than I pump through my coil while I'm heating up my strike water. I do this because I have a copper coil and want to remove any copper oxide (the green stuff) that can form in or on the tubing and can be toxic , If you are going to go stainless this is not a problem.
 
I use copper and my HEX coil is in the HLT, life is good.

I flush it after mash with hot sparge water and the outside (which only touches water) is a lovely brown oxidised color.

No fuss, no muss, no worries.
 
Wondering if someone can assist, I am looking at replicating Boerderij's HERM coil below but I am unsure about the compression fittings for the coil to the 90* elbow. My keggle has a 1/2" threaded port welded in, as such I need a male to screw into it, but then what do I need for the coil? A female receiver?

If this sounds confusing it is because...I'm confused. I guess I don't know how a compression fitting works on a straight tube. Do I have to flare the end of the HERM coil?

Any help is appreciated.


...


2 -> 1/2" tube -1/2" FPT Compression fitting (90 deg elbow) SS-810-8-8 $40.00 McMaster-Carr 5943K216 http://www.mcmaster.com/
2 -> 1/2" close nipple $3.44 Buy Fittings Online 27-4P1-1/8 http://www.buyfittingsonline.com/Fittings/item6592.htm
2 -> 1/2" Stainless Steel Washer $5.00 Bargain Fittings - http://www.greatbargain.net/order/shop2.html
2 -> 1/2" Stainless Steel Locknut $9.00 Bargain Fittings - http://www.greatbargain.net/order/shop2.html
2 -> 1/2" Silicon O-ring size 211 $0.50 Bargain Fittings - http://www.greatbargain.net/order/shop2.html

..................

Find the swagelok fittings on eBay by searching for "SS-810-8-8" or by searching "swagelok" and sifting through the listings.

This will give you a 1/2" NPT male nipple exposed outside the keg, from there you can connect it to your system however you see fit.
 
If you have 1/2" NPT couplers on the kettle for the hex you probably want to use a pair of these 1/2" NPT - 1/2" compression SS elbows.

Comp90-12Tx12MNPT-2T.jpg


You don't flare the tubing end, just slip the nut over the tube end followed by a ferrule, stuff the tube end inside the compression fitting and run the nut tight.
fwiw, I used these with nylon ferrules for plumbing my 1/2" SS hex so it can be undone if ever needed...

Cheers!

[edit]ps: while Bobby kinda steers one towards SS ferrules for hanging a hex the nylon ferrules have worked fine for a few years with my 50' hex.
 
Thanks for the help!
If you have 1/2" NPT couplers on the kettle for the hex you probably want to use a pair of these 1/2" NPT - 1/2" compression SS elbows.

Comp90-12Tx12MNPT-2T.jpg


You don't flare the tubing end, just slip the nut over the tube end followed by a ferrule, stuff the tube end inside the compression fitting and run the nut tight.
fwiw, I used these with nylon ferrules for plumbing my 1/2" SS hex so it can be undone if ever needed...

Cheers!

[edit]ps: while Bobby kinda steers one towards SS ferrules for hanging a hex the nylon ferrules have worked fine for a few years with my 50' hex.
 
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