HERMS COIL OPINIONS
Posted: Wed Feb 01, 2017 12:36 pm
by SoCal Surfer
I have a 25' x 3/8" copper coil for my herms coil I do not like the flow rate and am stepping up to 1/2 x 25' or 50'. Is 50' better because it's longer or am I just taking up space because all of the heat that has transferred be done in 25'. I recirc constantly and use a bucket heater to keep my HLT at a constant temp. I'm sure 50' will work but will 25' work just as well? I am doing 5 gallon batches. What works for you?
Re: HERMS COIL OPINIONS
Posted: Wed Feb 01, 2017 3:05 pm
by Charlie
I'm running 25 feet of 1/4 inch ID soft copper in a dedicated 4 gallon stock pot heated by a hot water heater element. With my March pump running unrestricted I get about 1 GPM through the coil, which I heard was about the right flow rate.
To hold the mash at 152F I set the stock pot at 154 and run the pump 10 minutes on, 10 minutes off. On cold days I might kick the stock pot up to 156 degrees. My mash tun wears a quilted jacket which insulates it some.
The 1/4 ID tubing works pretty well, so I think your 3/8 is fine unless you need a higher flow rate.
Charlie
Re: HERMS COIL OPINIONS
Posted: Wed Feb 01, 2017 3:55 pm
by Charlie
I see that I didn't address your question. There's a couple of ways to look at it:
* The smaller the tubing the higher the surface area to volume ratio.
* Faster flow (lower dwell time) means less opportunity for heating.
Long story short, I don't really know. I get adequate heat input using my 25 ft of 1/4 ID and a couple of degrees differential, so I think 50 feet is overkill.
Charlie
Re: HERMS COIL OPINIONS
Posted: Wed Feb 01, 2017 4:22 pm
by Charlie
The issue with my current HERMS is that I can't figure out a decent way to automate it. I'm thinking about going with the following system to save space and maybe get it under automatic control.
Sorry about satch bombing your thread.
Charlie
Re: HERMS COIL OPINIONS
Posted: Wed Feb 01, 2017 4:37 pm
by SoCal Surfer
maybe I am trying to solve a problem I don't have. I am pretty sure I have 1 gpm. I'll let it be for a while. But I'm not one for diagrams but this is what I did.
My pump runs constantly. As a result, my beer has been much clearer and my conversion has been great. I did an iodine test and was floored as to how well it converted in comparison to what I have done before.
The heater in my HLT is controlled by an ultrastat IIA with the temp sensor in the mash tun.
My mash temp is pretty rock solid. Maybe I don't need more flow at all.