HERMS coil questions

[fakr]

So, I'm going to throw a HERMS coil in my HLT so I can recirculate and maintain my mash temp.  

Anyone have any experience with making HERMS coils and mouting them in your HLT?

Specifics:

-would 3/8th ID be big enough?
-would 20 feed be long enough?
-Does it matter if part of the coil touches the heating element?

Any other advice would be great.

[fakr]

ah, found a good article...

http://www.theelectricbrewery.com/hot-l ... ank?page=3

[Chris Craig]

I would think 3/8 would be plenty big for recirculating the mash.  The wort is being filtered as it recirculates.

It doesn't really matter how long the coil is because you're going to use a PID to turn the pump on and off to control the mash temperature, right?  The pump would just have to stay on a bit longer to heat the mash back to temp.

I would avoid having the coil touch the element if I were you.

Question:  Are you using 2 PIDs for this?  One to control the HLT temperature, and one to control the mash?  I guess this would be the best way.

[fakr]

to be honest, I'm building this half fast, until I "acquire" a 20GAL HLT and build a new controller.  

for now, I have a 50L hlt, 1 PID with an alt circuit to turn on the pump at a set temp.  I only have 1 temp probe, and thought of just making a T junction on the return from the HERMS coil back into the mash tun so I'd ultimately be controlling the HLT temp according to the output temp of the coil.  

being temporary, and on the cheap, I was thinking of just haning the coil down into the HLT, hooking it on the side for now, and attaching the hoses with hose clamps....remember this is temporary for the next month or two.

[fakr]

When I get the 20GAL blichmann HLT, I think I'm going to build the HERMS coil the same as in the link I posted above...looks like a real pro job.

for now, looks like a 20 foot 3/8 ID copper coil, a few 90degree fittings on each end, making a hook to hang off the side of the pot, and a T on the output for the temp probe...

hope it works fairly well and does me until the next build.

[fakr]

Wanted to post an update.

I built the 3/8" copper HERMS coil, for a total of about $40.  Took about 30 minutes to solder together and clean up.

I used it last night and for the first time maintained a constant mash temperature for 60 minutes!  

This is very exciting, and I'm really wondering why I didn't do this sooner.  it was only $40 in material.


Note:  

I did not recirculate the hot water in my HLT around the coil in any way, so I'm assuming if I had have, I would have transferred heat more efficiently through the coil.  But to be honest, I don't think I'm going to bother, as this requires an additional pump and further complexity to the recirculation.   To compensate for not recirculating the hot water, I had to set the HLT temp a little higher to get the desired heat transfer.

To maintain a mash temp of 152F, my HLT was set to 170F.  If I recirculated the hot water around the coil, I probably could have set the HLT tem to something like 160F....and if I made the coil longer, probably even lower a temp....but like I said, to avoid further complexity, I'm just going to set it to a higher temp for the same results.

[Kyle]

very cool, I`m planning to do one of these as well. I take it you used brass compression fittings though eh. The stainless compression fittings for a half inch coil to half inch NPT are available at Bobby M`s BrewHardware.com site, but a couple of those alone runs $30 US.

[fakr]

I didn't use ball valves or compression fittings for this Kyle.  I did this on the very cheap and is a temporary setup until I get a bigger HTL.

this is just copper wound in a coil about the diameter of a keg.  90degree fittings were put on either end of the coil, both pointing up, and a length of copper pipe was added to each so they both reached the top of the pot.  I then put a couple of 90s together to form a hook of sorts that hooks the coil to the inside of the pot.  
At that point, I just slide on my 1/2" silicone hose to the coil...that's it....pretty basic and definitely not pretty...but it works.

I thought I had a picture of the coil, but I can't find it on my phone so I'll take a pic tonight and post what it looks like.

by the way, I use a 1/2" to 3/8" reducer on the coil to step it up to 1/2" for all the rest of the fittings.

[Kyle]

thanks - for the info, makes sense. I'm very interested in doing a HERMS setup once I upgrade my mash tun to stainless

EDIT; that is worded poorly. Switching to a stainless MTL has no bearing on a HERMS setup. It's simply higher on my list of brew sculpture renos.

[HappyHax0r]

Can this be done in a coleman cooler style tun as well? Or is that just a fire waiting to happen?

[Kyle]

I have seen a few people on HBT instal heating elements in their cooler HLTs.

[fakr]

Kyle, why would you need to wait until you upgrade your mash tun to stainless?  The whole point of a herms system is so you don't have to apply direct heat to your mash.

It's your electric hot water tank that heats up the coil, thus heating the wort traveling through it, which is circulated back into your plastic or stainless mash tun.

Maybe I misunderstood?

[Kyle]

oh - you are correct there. I'm upgrading to a new mash tun for some unrelated reasons:

- my current cooler is very bulky and hard to clean
- I currently have alot of dead space in the Mash tun, so I'm interested in a new one with a bottom drain (sanke)
- the out port on the cooler has started leaking (very minor, and repaired for now, but its still a sticky mess from time to time)
- I'd like to have my keg cooler back for the patio come nxt summer

[fakr]

still doesn't stop you from making a herms coil though Kyle, all you'd need to do is make a wort return hole somewhere on your mash tun...I put it in the center of the lid of my old cooler mash tun, and put a cookie type sheet on top of the grain bed with holes in it for even wort distribution...