2 vessel BIAB eHERMS concept test

I have started to conceptualize my next brew rig. I don't believe I have seen this concept before and I feel it will give me the ease of use and practicality that I am looking for.

I want to do a two vessel BIAB eHerms. I have it all planned out for process and equipment but I would like some feedback on the concept.

So I will have two pots one will be the HLT with HERMS coil. The other will be the BK/BIAB vessel. Single pump will run the HERMS. I will have 2 PIDs running temps. 1 PID will be for the HLT sparge water and the other will be for controlling the pump during recirculation. I will have a control panel where I can plug in both elements and the pump in two different locations so I can run the pump separate from the PID when it comes time to cool the wort.

Process hopefully this will help to make the system make sense.
1. fill both BK and HLT with water and turn on the PID for HLT and turn on the heating element for the BK.
2. Once the BK reaches strike water turn off the element and add the grain to a BIAB bag and mix well till I hit mash temperature then turn on the PID to control the pump for the recirculation.
3. once the mash is finished I will turn off the recirculation PID and unplug the pump from the PID and plug it in to a different circuit to control it manually. I will hoist out the grain on a pulley built into the stand and use the pump to sparge the grain with water from the HLT. making sure to turn off the element in the HLT.
4. once I have the boil volume I will turn the BK element back on and begin my boil.
5. close to the end of the boil I will fill the HLT with ice water and then recirculate through the herms coil to chill and whirlpool.
6. then gravity feed into carboy.

Thoughts and feedback about the concept? has anyone built this before? is there a build thread somewhere? All comments appreciated.

I do BIAB, so I'd be interested to see how this concept works out.

Why have a PID control the pump? Just recirculate through your HERMS the entire mash. Overall I think the system design is very weird though. I'm not trying to be negative and crap on your idea, but it seems like a lot of design/work/cost to still be doing a BIAB.

I also don't mean to thread crap but I assume you're looking for constructive criticism to shape your plans. It seems to me that there is no benefit to going with two vessels. You can accomplish the same exact thing using a single vessel with a protected element in the bottom or by using a more rigid basket to keep the grain off the element.

I've thought a bit about trying to incorporate even a crude sparge into a single vessel BIAB by trickling filtered but cold water over the grain basket as it's slowly being hoisted out of the wort. In reality, it's really only going to boost efficiency by a couple percent and I think I'd rather just accept whatever the no sparge number is.

The ONLY con I can see to a single vessel is that it has to be larger than any vessel in a multi-vessel setup, but not THAT much bigger. I'm figuring a 20g can handle a very big 10 gallon batch. My latest musing is to put dual 4500w elements in the bottom of the single vessel. 9000 watts during strike heating, then run them in series during the mash which would yield 2250 watts spread over two huge elements. That's ELWD (exceedingly low watt density), then back up to 9000 watts until boil is achieved at which time I may either go back to 2250watts or a single 4500. It sounds complicated but I'm pretty sure I can make it happen with simple button pushes affecting contactors or rocker switches if necessary.

If you really want to stick with an extra HLT/HERMS for some reason, that vessel could be as small as an out of commission corny keg.

yea the only suggestion i have is that pumps should not be controlled via PID/temperature input. controling temperature of the mash by controling flow rate of the recirculation gets to be unweildy. its best to directly control the source of heat.

if you have to do it that way, instead of cycling the pump on and off, its better to have a motorized ball valve on the output of the pump, and have the PID open and close the valve.

iijakii said:

Why have a PID control the pump? Just recirculate through your HERMS the entire mash. Overall I think the system design is very weird though. I'm not trying to be negative and crap on your idea, but it seems like a lot of design/work/cost to still be doing a BIAB.

Click to expand...

I can follow what he is proposing, but it does vary from the norm. I've thought about using my "spare" sanke keg to add a second vessel to my BiaB eKeggle setup for use as a HERMS setup, but that is as far as I've gone with it. I personally would not worry about sparging unless you plan on brewing thousands of barrels a year, the increased efficiency really doesn't get you that much over doing full volume BiaB. You could get about the same result using a single vessel recirculating mash using a false bottom. You'll still get some wort filtering from the recirculation, you should get 70%-75% overall efficiency, and still have very good temperature control during the mash.

I'm just thinking out loud here while I type, not trying to talk you out of something different.

audger said:

yea the only suggestion i have is that pumps should not be controlled via PID/temperature input. controling temperature of the mash by controling flow rate of the recirculation gets to be unweildy. its best to directly control the source of heat.

if you have to do it that way, instead of cycling the pump on and off, its better to have a motorized ball valve on the output of the pump, and have the PID open and close the valve.

Click to expand...

that makes a lot of sense. Tell me if i got this right.

So instead of using two pids: 1 to hold temp in hlt and one to turn the pump on and off. I could just run the pump the whole time and use the HLT PID to turn the heat up in the HLT to keep the Mash temps up in the BK/MLT?

Bobby_M said:

I also don't mean to thread crap but I assume you're looking for constructive criticism to shape your plans.

Click to expand...

Indeed I am. No worries. What you're saying makes sense.

But if I do a no sparge mash do I still need to dilute the boil volume and it would be helpful to put in hot water instead of cold water. So the HLT would provide hot water to dilute with. plus the mash recirculation and chilling benefits that come along with the HERMS.

is that correct?

Not as a rule. The guys doing traditional BIAB no sparge are mashing with enough water such that pulling the bag and dripping will yield 6.5g or so preboil. No dilution necessary. The only reason you wouldn't full volume mash is if you're going for a big beer and can't hold it all in the vessel. I'd say poor planning on that one... size the pot for the max that you'd ever expect out of the system.

Even if you had to dilute later, it would be a minimal amount and with the wattage I'm looking at, it wouldn't take very long to reach boil whether the dilution was hot or cold. Remember, it's rather common in a recirculation system like this to ramp to mashout towards the end so the initial volume is going to be around 170F anyway.

I have a system where the PID runs the pump. It works well... The system struggles a little bit to "learn" the resistance of pumping wort through boiling water, but it worked very well to conduct a step mash with my last Belgian saison. I am actually thinking of moving to a "no sparge" system where I put the entire boil volume into the HLT and allow it to recirculate just to maintain temps at the discretion of the PID. I would say that maintaining temps with the PID controlling the pump works well... stepping up temps can be a bit difficult, but that Belgian saison is an awful tasty proof of concept.