Designing a HERMS System

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Normans54

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Hey everybody,

After taking some time off of brewing to handle some work responsibilities, it is time for me to get back into the brewing game. I have about a half dozen brews under my belt and I am ready to take the plunge and start building a HERMS system. Unfortunately, I do not know how to do any metalwork or electrical wiring, so I had to get a bit creative. As such, I wanted to attach my design for my system so that I could get some feedback from the more experienced brewmeisters.

My plan is to drill two holes into the top of my mash tun, feed some food grade silicone tubing into each of them and seal them. Then attach the tubing to a chugger pump to feed it through a repurposed wort chiller sitting in my HLT to act as my HERMS coil which will then pump it back into the mash tun. I want to do it this way so that I can avoid compacting the grain bed, thereby leading to stuck sparges. I will hook the pump up to a Johnson thermostat controller so that it can automatically maintain the mash temperature. Then, I will use a propane burner to bring the HLT up to temperature, then shut off the propane burner and maintain the temperature with an electric bucket water heater hooked up to another Johnson thermostat controller. Then, when I am ready to sparge, I will attach the pump to the valve on the bottom of my HLT and pump the water into my mash tun. What do you all think? Do you have any suggestions? Thanks!

HERMS 2.jpg
 

microbusbrewery

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Based on your description and the diagram, you'll be pulling and returning from the top of the mash. It sounds like you're doing this to avoid a stuck mash. Assuming that is correct, there are a couple problems here. First, how are you going to prime the pump? Second, assuming you could prime, how are you going to prevent sucking up a bunch of grain and clogging the hose? Third, assuming you address the first two issues, pulling and returning to the top of the grain bed is going to result in uneven temps throughout the grain bed...kind of the whole reason for using a HERMS/RIMS in the first place. IMO, pull from the bottom using some kind of a false bottom to filter, and return to the top. That will result in uniform temps throughout your mash bed. Put a ball valve on the pump, throttle it back and stuck mashes won't be anything to worry about. I recirculate during my entire mash and I think I've only had two stuck mashes. And that's including some wheat and rye beers that were 40-50% wheat and/or rye malt. Pull from the bottom, throttle back the ball valve, use some rice hulls with significant amounts of huskless grain, and you'll be fine.
 
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Normans54

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Thanks for the advice. I appreciate it, as it appears that i would have run into problems with my current design. A follow up question just to clarify: if I attach the pump to the bottom and then add a ball valve to the output end of the pump, you are suggesting that, after I finish mashing, I close the ball valve and then reverse the pump to push what liquid is left in the tube back into the mash tun in order to relieve the pressure in the grain bed, thereby avoiding stuck sparges? Would I not have to worry about introducing oxygen into the wort by doing so? Thanks so much!
 

Bobby_M

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You'll have to move the heated mash through the grain bed for it to be effective so that requires removing the liquid from the bottom, heating, then putting it back on top.

The actuated pump version of HERMS is less effective than the constant recirculation method because the temp probe that triggers the pump may not represent the average mash temp. When the wort is static, there can be variable pockets of temperatures. In the constant recirculation method, the mash temp is purely regulated by the temperature of HLT.
 
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Normans54

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Bobby M, thanks for the response. So with the constant circulation method in this case, would I just keep the HLT temperature at whatever temperature I want to mash at and then shut off the pump and bring the temperature of the water up in the HLT when I am ready to sparge? I would imagine that constantly recirculating the mash through the HLT when the water is at the temperature I am going to sparge with would not allow me to keep the mash at the desired temperature, right?
 

oakbarn

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If you have a good false bottom and make the Mash a little wet, you will not normally have a "stuck" mash unless you have some oatmeal or other gummy adjunts. If you are doing that, add rice hulls. If you do get a Stuck mash, you can add a lillte more water by Back flowing from the HLT to the bottom of the Mash Tun.


We use a Chinzilla and two pumps and it works A+ as a herms!
 

Bobby_M

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Bobby M, thanks for the response. So with the constant circulation method in this case, would I just keep the HLT temperature at whatever temperature I want to mash at and then shut off the pump and bring the temperature of the water up in the HLT when I am ready to sparge? I would imagine that constantly recirculating the mash through the HLT when the water is at the temperature I am going to sparge with would not allow me to keep the mash at the desired temperature, right?
Yes you can do it that way but you can also start ramping the HLT temp up to 170F at about the 30-45 minute mark which gets the mash up to mashout and the sparge water up at the same time.
 
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