Herms Design Help/Questions

I am wanting to build a HERMs brew stand with PID control. However I have a few questions based on the different systems I have seen here. I am a pretty new AG brewer, and understand most of the terminology, but do not have enough batches under my belt to say or sure, if Batch or Fly Sparging etc is best. I would like something with the most flexibility.

As far as temp control for the MT my understanding is it is best to put the thermocouple in the recirc output and control the heat based by adjusting the heat of the HLT where most people have a cooper coil.

What do you do when heating sparge water, if the MT is not calling for heat?

Sight Glasses - I understand the one on the HLT to know how much strike/sparge you have, and how much you have dispensed, and on the BK to know how much volume you have collected/boiled out.

I am using 50L kegs for all my vessels, this leaves me a little short on 10gal batches since I only have 13.3Gal of BK capacity.

Would I run into any problems with boiling in two kettles and perhaps pushing 15 gal out of the system. Seems like I could mash 30-33 lbs with a 13 gal MT. I would make sure the two kettles where well mixed before the boil and blended again after the boil for consistency, unless I wanted to do different hops/partygyle etc. This seems like it adds a lot of options, without adding the cost of importing a large BK (I hate shopping for crap here in Guatemala, 2 days of hunting around for something second rate.)

I am leaning towards an electric HLT/Hot water source for the herms coil because driving an electric heater with a PID is something I know.

What is everyones thoughts but the HERMS coil in the HLT, or use a seperate chamber/ shell and tube with a second pump etc?

Thanks!
GuateBrewer

I'm new to this too and am putting together a similar electric PID / HERMS system as you, but from what I understand the theromocouple in the MLT (whereever you end up placing it exactly) isn't used to control the HLT burner or element but to turn the pump on/off that recircs the MLT fluid through the coil in the HLT.

You set the HLT to (say) 180 after you've got your strike water in the MLT and the pump/PID will recirc depending on the temp you set based on your rests or just to keep the temp constant.

Kal

Kal,

Thanks for the info, I guess the main issue we need to be considering is PID vs On-Off controllers as well as thermocouple placement.

A PID on a march pump out of the box would likely smoke the pump cycling on off in millisecond bursts. My experience with PID's is in the heating side of process control and an electric heater does not really care if you pound it on and off all day long.

I have been reading and re-reading this HERMS Design Specifics

But I guess like all things in brewing there is good enough, more good enough, and better good enough. Its just hard to figure out what level of good enough I want to be in. I mean people have been making good beer with just a few coolers and turkey fryers, but for me the electronics side of things is more interesting than the sitting around and watching water boil...

I used to use an on/off controller to control my pump and keep my HLT (containing heat exchange coil) at a constant temp. The controller would turn the pump on when Mash tun temp dropped below the set point. Now I recirculate constantly and use a PID to control the HLT temp. I put my thermocouple where the wort returns to the top of the mash tun. I know from trial and error that if I set the PID 2 F above desired mash temp that I will acheive my desired mash temp.

Interesting guys.

GuateBrewer: Good point about the March pump cycling on/off. Never thought about that.

SteveHaun: If you pump continually use the PID to control HLT temp during mash, what happens when the mash is over and you need to sparge? ie: what if the HLT temp has gone over 170F (too high to sparge)? Or is that not a problem as if you're constantly recirculating odds are that the HLT will never go over 165 or so to keep the mash somewhere in the 150's.

The more I think about it the more I like the idea of having the March pump constantly recirc. Better for the pump and will also give you very clear sweet wort.

Lots of thinking to do still... I'm still a month or two behind that stage.

Kal

Kal:
I think your concern about the sparge water temp is appropriate. I usually mash-out and set my PID temp at 175 and stop when my mash temp (thermometer in the mash tun) reaches 165. I batch sparge. I then drain the mash tun and then pump in the sparge water. I don't measure the temp of my sparge water but I have measured the temp of the grain bed which is usually in the low 160s after stirring. One could minimize the risk of too hot sparge water by setting the PID temp during mash out to 165-170.

Well this is how min work I have a HLT and a copper coil in it. Its is heated and controlled by a hotwater tank heatinig element.

My mash tun is just a 15.5 gallon converted keg with a bazooka screen that I made out of copper pipe and ss screen from a sink Hose,.

For me I fill the HLT with water and set my pid pump what ever I want my dough water I want in my MLT then start pumping the wort through my coil and set my PID to what temp I want.

My temp probe is on the out put on the coil.

My hoses are all quick disconnects. Simple swapping of hoses.

all of your questions will be answered here.

this guy has a neat electric herms setup.
The Powers Home Brewery