eKettle: recirculating vs. non-recirculating

[adpostel]

I am limited on searching here at work, so I'll just ask the question.

What are the differences between having a recirculating system as opposed to just having the heating element in the brew kettle?
My objective is to build an electric HLT with PID control for my 3 vessel system.
Or possibly even build it to do BIAB batches as well, when needed.

I have read a ton of info on here, but one thing I can't seem to find is the answer to the original question.

Oh, also, my 3 vessel system consists of 2- 9 gallon SS Kettles and a 10 gallon round cooler MLT w/false bottom and CF plate chiller. Objective is making strictly 5 gallon batches. So the most water I would need to heat to a specific temp would be 6-7 gallons. ..

 

[iijakii]

Honestly the main difference is bling because people want to use stainless steel pots instead of coolers for their MLT. If you're using a cooler to mash in, and have a 3v setup doing batch-sparges, you don't need to recirculate to control temps. If you move to SS mashtun or a no-sparge system you'll absolutely need to recirculate to control temps.

 

[adpostel]

Thx for the response, but I am mainly referring to the HLT. I am wanting to build a PID controlled HLT. And the question is do I have to have something to move the water around in it, or can I just use the heating element only? I am trying to avoid using a pump to move the water around in the HLT. I am wondering about temperature differential within the HLT, is there a differential, or is it negligible?

 

[hillhousesawdustco]

Pretty negligible within the HLT itself. I have a coil inside my HLT to recirculate the mash and raise temp to mash-out (also works as a heat exchanger post-boil) but don't have anything circulate the water in the HLT other than a spoon. There is a small difference between the placement of PID-thermostat and the top and bottom of the HLT, but it is pretty easy to adjust for. G'luck!

 

[adpostel]

Man, that is good to hear. I'm gonna put one of those things together, it should provide some, set it and forget, it ease of operation for the strike and sparge water, and hopefully some consistency.

 

[processhead]

I have used a propane fired HLT and now have one heated by an electric element with manual controls.

Neither arrangement has ever left me feeling like I needed a PID controller for heating strike water or sparge water.

All you need is a thermometer to monitor the kettle temp.

 

[hillhousesawdustco]

I'm sure the manual set-up works beautifully under appropriate supervison but I have to say that I love setting a temp on my electric PID-controlled HLT and then wandering off for a while to do other chores to come back and find it right where I set it.
A PID is also just the bees knees if you add a coil in the HLT- maintaining mash temps and ramping up to a 168 mashout with the push of a button is pretty great.
I have a totally manual propane boil kettle, and love the hands-on aspect of that. I also love the flexibility of my fancypants HLT, so just find what works for you!

 

[adpostel]

I agree with hilhouse, while there are several ways to heat up water, I dont see anything wrong with using technology to increase efficiency and consistency. Heating up strike water, sparge water and mash out water to very specific temps can be done with a heating source and a thermometer, that is correct. But my personal objective is to be able to control those temps throughout my brew session, which allows me to focus on other things like crushing grain, measuring out hop additions, getting the chiller setup, and enjoying a homebrew, all without having to have my handheld thermometer over my HLT several times as it is heating up. I am still doing a 3 vessel process, just automating the part, which in my opinion, is the most important, but yet tedious.

 

[BadNewsBrewery]

I'm not 100% sure I get the question as there are two possible 'recirculations' you could be mentioning, and both have been addressed here.

1: Recirculating the mash in either a HERMS or RIMS style setup, where you're constantly recirculating the mash through some means of temperature control (HLT in HERMS, or an element in a section of pipe with RIMS). One advantage of this setup is that you can hold mash temperatures very accurately. As mentioned earlier, if you have a standard cooler type mash tun, you won't notice a ton of heat loss anyways, so it may not be worth it. The other advantage of this style of recirculation is that you can do variable temperature mashes, with lower and higher steps and even raise the temperature up to your mash-out temps. This can be done by adding boiling water or by doing decoction steps, but doing it via PID and changing the HLT / RIMS value is viable and some prefer it.

2: Recirculating the water within your HLT for a HERMS type setup. This is done to allow for a unified or 'homogenious' temperature throughout the HLT, so that your temperature probe is reading an accurate value for the HLT temperature and so you don't wind up with hot spots. I would say this is a fairly important step, and can be more or less important depending on your tank layout; where is your heating element, where is your temperature probe. Given my layout, I can get 30-40* differences in temperature readings when the pump is off vs when it is on - granted, my temperature probe is in a T connected to the discharge, just before the valve, so this area cools down rapidly. There have been reports of people seeing 5-10* differences with the probe located directly in the HLT though. Alternatives to recirculation pumps are stirring (either manually or mechanically) or even the use of bubblers, which has been suggested but I'm not sure if it's ever been implemented. Some method of aggitation in the HLT to mix and distribute the hot water is definitely important to maintaining accurate and steady temperatures.

Good luck in your quest,
-Kevin

 

[adpostel]

Thanks Kevin, my question relates exactly to #2 in your post. I am not doing a RIMS or HERMS system, only using the PID controlled heating element to get strike and sparge water to specific temps, and the temp differences within the HLT that I would see if I didn't have anything to move the water around in it.

 

[cgherrington3]

I use a cheap harbor freight submersible pump in my ebiab keggle set up with PID. It cuts my time to temp in half and the heat is even. Without the pump you have a column of hot water and the edges will be cold.

 

[Bobby_M]

I have used a propane fired HLT and now have one heated by an electric element with manual controls.

Neither arrangement has ever left me feeling like I needed a PID controller for heating strike water or sparge water.

All you need is a thermometer to monitor the kettle temp.

This is not a jab at you at all but I think if you had the opportunity to brew one time with a PID on the HLT, someone would have to pry it out of your cold dead hands before you went back to manual gauge watching.

 

[Bobby_M]

Thanks Kevin, my question relates exactly to #2 in your post. I am not doing a RIMS or HERMS system, only using the PID controlled heating element to get strike and sparge water to specific temps, and the temp differences within the HLT that I would see if I didn't have anything to move the water around in it.

The PID's temp probe can easily sit in a pocket of either hot or cold water and it wouldn't reflect the average temp accurately. If you don't mind giving the water a stir from time to time, and especially right at the end when you think you've hit your target, no problem. You can use an aquarium air pump to pump some air down to the bottom of the pot which causes turbulence. You can also mount a small 60 RPM clock motor in the lid of the pot and have a small stirring shaft sit in the water.

 

[rgauthier20420]

The PID's temp probe can easily sit in a pocket of either hot or cold water and it wouldn't reflect the average temp accurately. If you don't mind giving the water a stir from time to time, and especially right at the end when you think you've hit your target, no problem. You can use an aquarium air pump to pump some air down to the bottom of the pot which causes turbulence. You can also mount a small 60 RPM clock motor in the lid of the pot and have a small stirring shaft sit in the water.

Once I make the jump to an eHLT this is the plan. It's simple and cheap enough to wire in a switch and outlet to your panel and turn a small motor to stir your water, or maybe turn on the pump to do a little circulation.

 

[BSD_Glass]

I recirc my eHLT with an aquarium pump and find it fully adequate as far as equalizing temps in said vessel. It was a lot cheaper than a second Chugger.

I took a corny dip tube that had a hole near the "top", cut the bottom off so it was close to the bottom of my kettle and soldered the tube, to a ball lock gas in connector mounted through the lid. I plug the air pump into the corny gas in quick connect and Bob is, as some would say, my uncle.

I had a pretty powerful older style aquarium pump laying around from my sculpture days at art school. It would push air through a 6' column of 6" acrylic tubing filled with water with a nested 1.5" tube inside the water holding a neon tube (no water touched the neon, ever) but I think any old $5 aquarium pump would move enough air to circulate a HLT just fine as regards stratification.

On my HERMS system, I switch from a RTD in the HLT to a RTD on the output of the Herms coil when I'm recirculating the mash and it settles down to my chosen temp fairly quickly. I'm not seeing much for temperature changes as I run my HLT into the mash tune while fly sparging except for a slow drop in temp (I turn off the element when I start sparging so as to not forget and dry fire it.)

Cheers.

BSD