Pumps and PIDs

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Hopsteep

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I’ve just ordered some shiny bits and bobs from the BrewBuilder in order to upgrade my two vessel system. The new stainless coil will double as a Herms and Immersion cooler (with a bit of luck) and I’m including ports to allow me to whirlpool.

My DIY skills aren’t particularly proficient when it comes to electrical wiring and soldering, although if push comes to shove I’ll gladly have a go. Once I’ve fitted the herms bits and bobs the next thing will be to fit a pump and a PID.

I know several people have asked on here about solar pumps and there are mixed reviews from what I’ve read. The pump I buy needs to be able to cope with some stray bits of grain and be able to be throttled back mechanically with a ball valve (just to keep it simple for now).

During the mash, I’ll need a temperature controller / temperature probe. What do people use (ideally something plug and play like my trusty Inkbird fitted to my fridge) with their HERMS?

Please could anyone recommend a cheap pump fit for purpose, and offer some advice for fitting a temperature probe and controller.

Thanks in advance,

Sam
 

uDicko

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Can't recommend one but I will say don't get the brown one, solar pump. I can vouch for its tendency to freeze with the odd grain. PITA
 

BeerCat

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You will need to male a PID costing around £50. Inkbird sell them or Aubergine I think. Fairly straightforward to wire.
MALTMILLER sell a decent pump for £85, as said above the cheap brown pumps are prone to freezing. I threw out 4 broken ones. You will need a new temp probe for the PID as well. Depends where you want to put it. Possibly on the output of your mash tun.
 

Hopsteep

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Awesome thanks for clearing that up. I guess there’s not a cheap mag pump out there.

Having had a look at other threads I’m leaning towards building my own controller. We will see.
 

peebee

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The irony is the little 12V pumps are more powerful and more efficient than the 230V behemoths. But that's because the big pumps have big tolerances (gaps) which is why they can handle mucky water/wort. But it needs a powerful motor (probably 230V) to overcome the inefficiencies. £70-75 should get you one (wow, when I was building my brewery not so long ago, £140 was about the cheapest!). For pumping clear water the little 12V jobs are fine, so any brew system using two pumps are best designed to avoid the need to pump clean water and dirty wort with the same pump wherever possible.

Those IPB-16 jobbies look the business. I'd probably go down that route if I was building my brewery now. The links are American though; you might try https://www.amazon.co.uk/Inkbird-Pre-Wired-Thermostat-Temperature-Controller/dp/B072JW5F66/ref=smi_www_rco2_go_smi_g8682124849?_encoding=UTF8&%2AVersion%2A=1&%2Aentries%2A=0&ie=UTF8 (out of stock currently) because you want to be sure it'll work with UK electrics.
 

Druncan

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I like pumps!!!!:rolleyes: I got this for big transfers; https://powellbrewing.co.uk/product/wort-transfer-pump-2/ It primes easily and reverses. It sucks so hard it collapses re-inforced tube and needs throttling. I was advised that it switches off @ > 90*C, but have never run anything above 85*C. I also have a 240v china mag pump I got it for £50 two years ago; I regularly have to dismantle the head to clean gunk off the impeller. https://www.ebay.co.uk/itm/Magnetic-Drive-Pump-15R-With-304-Stainless-Steel-Head-Beer-Brewing-220V/273844323604?hash=item3fc264c514:m:mF8MfC69VL-HgyVCZwEFXLg more expensive now,,, I am also using a 12v pump https://www.ebay.co.uk/itm/12V-Solar-Hot-Water-Pump-Circulation-High-Quality-Food-Grade-100-C-CoupleUULK/264221256471?hash=item3d84d06b17:g:tGcAAOSw1Fda5A-k it's fitted in a bodged peltier keg cooling system. All great, all work fine!
 

blawford

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Awesome thanks for clearing that up. I guess there’s not a cheap mag pump out there.

Having had a look at other threads I’m leaning towards building my own controller. We will see.
I own this pump - https://www.kegkingdom.co.uk/products/brew-pump-3000. Has been great so far for the money, I use it for re-circulation and never hand any issues with grain, easy to dissassemble and clean.

Can be bought in various places if KegKingdom isn't to your liking (I seem to remember people complaining about them, they were fine with me at the time). https://www.angelhomebrew.co.uk/en/pumps/385-ahb-diablo-homebrew-pump.html and they have an uprated version https://www.angelhomebrew.co.uk/en/pumps/386-ahb-diablo-plus-homebrew-pump.html. I have always found the basic version that I have more than powerful enough if your hose length isn't too long.
 

Hopsteep

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Fitted the immersion cooler/HERMS coil this morning, as well as two ports for whirlpooling. I'm pleased with how it's looking. I need to wait for some silicone washers to turn up before leak testing as I didn't order enough.

fullsizeoutput_8d2.jpeg fullsizeoutput_8d3.jpeg
For fitting the pt100, am I right in thinking that having it connected to a T-piece on the inlet of the mash tun is the right way to go? And if so what method of fitting it do most people use? Do people blank it off and then drill a 14mm hole to fit it or use a 1/2'' BSP to 1/4''BSP reducer or similar?

This is my rough idea for the lid of the mash tun...
IMG_8786.JPG

There's no rush as this will be a gradual upgrade. I'm not likely to invest in a pump for a few months, but want to get everything set up and ready to go.
 

Hopsteep

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As far as I am aware most people place the probe on the output of the mash tun. That's how I trun mine. Love your build, what size kettle is that?
Interesting... would it not make more sense to control the input temperature of the mash (my mash tun is a converted thermopot so heat loss would be very little) although time taken to recirculate wouldn’t be long I guess. So I’m probably overthinking this!

It’s bergland 50L pot. My mash tun is also a 50L giving me the option to increase the size of the copper one day if I wanted to.
 

BeerCat

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Interesting... would it not make more sense to control the input temperature of the mash (my mash tun is a converted thermopot so heat loss would be very little) although time taken to recirculate wouldn’t be long I guess. So I’m probably overthinking this!

It’s bergland 50L pot. My mash tun is also a 50L giving me the option to increase the size of the copper one day if I wanted to.
From the basic testing i made i found it to be reasonably accurate. Sticking a thermometer in the mash gave me the same reading. I am only recirculating through one vessel though. There is an excellent article from another forum here by @peebee . Well worth a read.
 

peebee

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... There is an excellent article from another forum here by @peebee . Well worth a read.
Thanks very much! Blimey, I've just come off another thread where my post's on Jim's were getting referenced. I'll be getting a tap on the shoulder asking to explain why I'm encouraging locals to go off to Jim's!

I was actually preparing to repost it on here. It covers "one-pot" designs too now. It was interesting writing the original (15 months ago) because it changed my opinion of the best place to put a temperature probe; I hadn't appreciated a "feed-back" mechanism using a commonly chosen position made it an excellent choice - "feed-back" mechanism … good grief, hardly surprising I didn't appreciate it.

It'll come together in a following post. Put your feet up and sup a coffee (or beer?), 'cos it's big!
 

Hopsteep

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Thanks very much! Blimey, I've just come off another thread where my post's on Jim's were getting referenced. I'll be getting a tap on the shoulder asking to explain why I'm encouraging locals to go off to Jim's!

I was actually preparing to repost it on here. It covers "one-pot" designs too now. It was interesting writing the original (15 months ago) because it changed my opinion of the best place to put a temperature probe; I hadn't appreciated a "feed-back" mechanism using a commonly chosen position made it an excellent choice - "feed-back" mechanism … good grief, hardly surprising I didn't appreciate it.

It'll come together in a following post. Put your feet up and sup a coffee (or beer?), 'cos it's big!
 

peebee

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Deciding where to put a temperature sensor in a HERMS ("Heat Exchanged Recirculating Mash System") can be perplexing, especially if the sensor is feeding back to a "PID" controller that automatically manages the heating element in the HLT ("Hot Liquor Tank"). And therein lies the source of disagreements. HERMS uses the heat exchanger to manage the heat in the mash liquid, and therefore the mashtun: But HERMS does not control the flow of heating liquid through the heat exchanger (as is the case in many other process control examples), instead it controls the temperature of the water in the HLT. This difference opens up different ways of thinking compared to many examples published about heat exchanger process control. RIMS heats the mash (process) liquid directly so avoids these arguments (but generates a few of its own).

Let's start with a somewhat stylised diagram of a HERMS setup.
HERMS.jpg


RIMS ("Recirculating Infusion Mash System") is much the same but the element ("E") is actually in the recirculating mash so there is no HLT holding the heat-exchange coil of recirculating mash. The element is going to be electric in RIMS but a gas burner could be used to heat the HLT for HERMS (more likely it is electric too - I've never seen a gas version but they exist).
RIMS.jpg


The diagrams illustrate the four likely locations for placing a controlling temperature probe: A, B, C and D. The pump ("P") recirculates the mash. Ideally all four locations read the same temperature, and they will for all minor changes to temperature; the actual location of the temperature probe becomes important when big hikes in mash temperature are being made, either when initially heating to the mash temperature or stepping the mash temperature up for stepped mashes or "mash out" at the end.

The advance that has come with both systems (HERMS and RIMS) is the "recirculating" bit. The mash liquid is separated from the grain (by a false bottom or the like), heated, and then returned to the grain. Previously insulation was the prime choice for keeping the mash temperature steady, or else heat was applied directly (there are also methods of manually separating portions of mash and heating it, such as in "decoction" mashing). The problem with directly heating the mash is the high proportion of solids in a mash which limits heat transfers to slow conduction, not faster convection (with associated currents), which will create pockets of cooler or hotter mash unless stirred well, and the solids can burn to the heating surfaces. Constant recirculation also stands in for convection currents, keeping the temperature throughout the mash more consistent.

"A" is one logical location for the temperature probe controlling heating of the mash i.e. in the tank with the heat source (the HLT). But is it the best? The most likely controller being used is of the "PID" type, because they are very good, but unless they have been very carefully tuned they can also be horribly slow at converging the set (desired) temperature with the actual temperature. And placing the probe at "A" has the effect of exaggerating this slow convergence. Tuning could accept a small temperature overshoot to speed up convergence, but most users are not going to be developing the necessary knowledge to fiddle about with these controllers in such detail. As a location for the controlling temperature probe in HERMS "A" may require a complete shift of thinking to select. No wonder the sensor location for HERMS causes such division of opinions.

"B" is a logical location for the temperature probe in RIMS because there will be no location "A". Location "B" (and "C" and "D") is actually in the recirculating mash stream. Many documented examples of heat-exchanger processes will show the location of temperature sensors at "B".

"C" as a location seems to be ideal because it's in the mashtun (MT) with the mash. But even with recirculation, temperature through the thick stodgy mash can't be guaranteed uniform so isn't a good candidate for a sensor controlling mash temperature.

"D" would seem a reasonable location, but there would be considerable lag between heating and seeing the result at "D". Meanwhile there would be undesirable over-heating of the recirculated mash unless very careful tuning was undertaken (far more so than if "A" was used - somewhat defeating any point of not using "A"). "D" is a good location for monitoring because it will help confirm when the system has achieved equilibrium (i.e. heating has done its work to reach the desired temperature and the system is now just maintaining it): Without such monitoring the system can be the source of uncertainty.

So, what of "B", the same location as would be logical for RIMS (the HLT and HERMS coil sort of replaces the RIMS tube). Can this be a better location than "A" for HERMS? When temperature changes are small the sensors at "A" and "B" will most likely be reading the same temperature. But for big jumps the heat exchanger may start lagging behind the speed at which the HLT is being heated. Meanwhile if the sensor is at "B" the controller could be allowing the HLT to over-heat (the controller is being told the temperature is too low): But that will also mean the heat-exchanger will not be lagging behind the desired temperature by quite so much (because more heat is being provided to the heat-exchanger). And as long as the mash is sucking enough heat out of the HLT for the over-heating to stay within "reasonable" limits, the over-heating should get less and less as the desired temperature is converged on.

So "B" is ideal? Minimal tuning yet much of "A's" slow convergence is countered. This does depend on the dynamics of the brewing setup design but this can be ignored for most brewery designs. Some may not want to risk "B" and will stick with the "safe" sensor location of "A" (over-heating the HTL is very unlikely). Even if a brewing setup is found to be incompatible with this "B" approach, a far coarser and cheaper controller (than a PID controller) could be used on the HLT to limit its potential over-heating. The amount of lag between the HERMS coil and the HLT will depend on the flow rate of mash fluid through the coil (and the efficiency of the coil - note "rate" must take in the possibility of a stuck mash) so using location "B" releases the convergence of actual MT temperature and desired MT temperature from those factors too.

But there is a snag (for HERMS). If any sensor location other than "A" is used to control the temperature of the MT, the HLT cannot be heated using the same PID controller unless the recirculation system is operating. This might not be an issue for many, and it will not be a problem to work-around for the handy folk who would like the challenge. But the limitation may prove unsurmountable for some, in which case using location "A" is the only option. Another snag when not using "A" (for HERMS) is if recirculation is interrupted (e.g. stuck mash): The controller may continue to instruct the HLT to keep heating (until it is boiling unless some sort of fail safe is worked in).

So to gain the potential benefits of using location "B" for HERMS (i.e. possibly faster temperature ramps) you must accept the HLT is out-of-bounds for ad-hoc little heating jobs when the recirculation isn't running. But would the HLT ever be required when the recirculation isn't running? The handy might develop a scheme to switch between locations, or work in a second controller for independently running the HLT, but such complexity is outside the scope of this article. But this division of options should keep arguments raging for some time to come. Or avoid this divisive option and plump for RIMS, but be warned the choice of RIMS over HERMS is just a source of even more arguments!

Finally there are the "one-pot" designs such as the popular "Grainfather":
ONE-POT.jpg


Look at it carefully. All that has changed from the RIMS diagram is the position of the element. The "One-Pot" designs are RIMS! The temperature probe will frequently be sited at position "D", the position not recommended in the discussion above. But position D and B are near enough identical in this case. There is no position "C" because this design will have the grain contained in a basket, or "malt pipe", which makes position "C" awkward if not impossible.
 

peebee

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An interesting little detail in some real-life HERMS data logging (not my data-logging); shows the "feed-back" mechanism I mentioned, in action (showing two mash "steps" but as this was a test there wasn't a mash "rest" and it just went on to the next step):

Temperature (vertical) against time (horizontal). HLT temperature in black, Mashtun temperature in brown. The HLT over-heats to start with (by 4-5C in this case) then slides back to meet the mashtun coming up to set temperature. Thus compensating for any tendency for the mashtun temperature to converge slowly with the intended (set) temperature.
 
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Hopsteep

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Wow, thanks for that. I must admit I’ve read through a good 3 times so that it all sinks in! acheers.From what I gather, no method is perfect unless you’re a genius with circuits and wiring and have the ability to factor in readings from multiple points in the brewing rig.

I think I will stick with my original plan and fit the probe to the mash tun inlet. If it’s not working the way I want it will be really easy to reposition it. That’s the beauty of home brewing and enjoying getting hands on with your equipment I guess!
 

Hopsteep

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Quick update, on my quest to upgrade my set up I picked up a stainless steel catering table last night. The thing is solid. A little corroded from being stored outside, but nothing that can’t be sorted with some elbow grease. The best bit is it was only £50 clapa
I thought this was a bargain but my girlfriend was not impressed. Especially when I pulled up in the drive with it hanging out the back of her car :onechug:
 
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Hopsteep

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The brewing gear is retired now until the new year- I have a chocolate stout and a lovely ESB kegged ready to go in the bar and a batch of bitter bottled in reserve acheers.
So the upgrade resumes! I’ve just ordered the inkbird PID, 40a SSR and heatsink. For the probe I’ve ordered brewbuilder’s PT100 that’s threaded and a reducing bush so that I can house it in the t-piece for the inlet of the mash tun.

Some more exciting news- I’ve been dropping hints about getting a pump to my better half and a box from BrewUK arrived the other day. Hopefully my hints did the job!

No doubt I’ll get confused trying to wire up the PID so watch this space :beer1:
 

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