Questions for electric herms guys.....

[swanwick]

So @KyBeer when step mashing, are you taking the HLT up to 5-6f above the next step temp each time?

Did you ever think about keeping the HLT at the next scheduled step temp and then turning the Mash Re-circ pump on and off as needed to keep the right temp in the Mash (via probe in Mash)?

It seems to me that way you would only have the pump on part time to maintain temp during a step and could turn it on full bore when transitioning steps until target temp is reached (HLT would be on its way to following step or sparge). Seems that would hit target faster than your current 1f per minute starting with HLT at previous mash temp (or a few degrees above).

Disclaimer: I am in the process of setting up an automated electric HERMS system and working on the final design tweaks. Do not have brewing experience with the plan above. My actual brewing experience is with a 3-tier gravity system that I am retiring.

 

[swanwick]

In thinking about this a little more, it seems that with the pump on only part of the time (assuming no stirring help also), there could easily be temp stratification in the mash (hot on top, colder on bottom). Seems for what I am suggesting, there would need to be a HERMS bypass so that the re-circ could be continuous. When temp dropped below target, it would send through HERMS. When at or above target, it would just send bottom wort to top. This would probably only make sense in an automated brewery.

Wondering if this approach would create wide swings since the temp probe is at middle of pot. By the time new hotter wort had partially reached probe, there would be half a pot of hotter wort above.

 

[Control Freak]

I run my circulation pump throughout the entire mash time. I agree with your premise regarding uneven temperatures. As far as the design of the system, don't skimp on the coils both heating and HERMS. You may want to talk to Bobby at BrewHardware.com, he's a great source of information and is more then willing to help.

 

[swanwick]

So what temp are you keeping your HLT? If your pump is on continuously, you can't go too far above desired mash temp and then when you want to raise the mash temp for step or mashout/sparge you can only do it at the speed that your heat source can raise the HLT and the MT. I have 5500w element, but the temp rise would be faster if I already had the HLT at the new desired temp and now just needed to keep it that way as I raised the MT quickly to same level.

 

[Control Freak]

My system has a 4-5 degree differential which stays pretty constant.
You'll definitely get to mash out faster if you start with higher temp water in the HLT but you should calibrate your heat loss and see if it's worth it.
My system gets a 1 deg. rise in 41 seconds (Avg. 10 minutes to get to mash out ) so I'm content just to let the HLT do its thing.
If your designing your system don't skimp on the HLT coil, get the biggest one you can comfortably fit in the kettle. More surface area definitely works to your advantage.

 

[Mad Mann]

There is a Temperature Differential between the temp of the HLT and Mash Tun and it varies with each system. In order to get the best control the HLT has to have constant recirculation. The best place to monitor the temps are at points in the circulation loops. As far as stirring the mash, it's recommended that you stir the top 1/3 of the mash which prevents it from becoming overly compacted. In addition once your system is dialed in avoid opening and closing the kettles this accounts for a lot of heat loss.View attachment 764662

Where is the best location to take the temperature, the inlet or outlet of the mash tun?

 

[Control Freak]

My probes for both the HLT and MT are located just at the outlets.

 

[swanwick]

Where is the best location to take the temperature, the inlet or outlet of the mash tun?

Thx @Control Freak I will have to "play" with it a bit to dial in. Do you know if water is a close enough approximation for testing as compared to soaking grain bed? Would prefer to have a decent sense of differential before first batch on newly built system.

@Mad Mann I have probes in the HLT and MT ~1/3 of way from bottom of each (Stout Tank thermowells). I am also planning to add a tee with a probe where the HERMS returns to the MT. Then will evaluate via experience what combo of those probes should drive the HLT heating element. Sounds like most people believe the Mash return is the right one to use.

 

[Control Freak]

I would go with water to get your starting points then when you add the grain your settings will change but not radically. I found that when I tuned the PID a second time with the grain in the system it only took a few minutes to complete. Running water will give your boil off rate, temperature rise times, as well as the percentage to set your boil kettle PID. Usually 70-75%.