Constructing a Homebrew Lauter Tun with PID Temperature Control

[nicktay]

Hello All,
I'm currently upgrading my homebrew equipment, in order to have more control over the whole brewing process. At this point, I use store bought malt extract (sugars extracted from grains) to create the fermentable liquid that becomes beer, but I would like to start brewing with all grain and perform the sugar extraction process on my own.

That having been said, what I plan to construct is what is referred to as a lauter tun. It will be a 10 gallon insulate container in which near boiling water is mixed with grain, and the temperature of the water, grain sludge must be temperature controlled. Current options I have to control the temperature are an electric heated rod or a recirculation system with a heat exchange. I decided, after some research, to employ steam heat. Steam heat has advantages over the other options because heat is transferred more quickly and it is cheaper.

For the container I plan to use a Gott 10 gallon cooler. I plan to use a PID temperature controller with a temperature probe to monitor the temperature of the liquid and control the functions I need to control. To employ steam heat I plan to purchase an electric pressure cooker and fasten plumbing to it which will run through a solenoid gas valve to the lauter tun. The steam will exit through nozzles into the hot liquid. In order to distribute the heat evenly, a motorized stirrer will mix the concoction.

The problem is I need to have the valve turn off when the liquid has reached its target temperature, the pressure cooker must turn down (but not off), and the motorized stirrer off. When the liquid is too cool, I must have the PID controller turn on the valve so that it opens, turn on the pressure cooker, and turn on the motorized stirrer.

I 'do not really understand at all how these components will connect and I do not wish to destroy them or myself when connecting them.

PID- http://auberins.com/index.php?main_page=product_info&cPath=1&products_id=3
Probe- http://auberins.com/index.php?main_page=product_info&cPath=3&products_id=55
Valve- http://www.stcvalve.com/Solenoid_Valve_Specification_2V025.htm
Pressure Cooker- http://www.target.com/gp/detail.html/176-7444481-0450846?ASIN=B001AQDAFA&AFID=Froogle&LNM=B001AQDAFA|Deni_Electric_8.5_qt_Pressure_Cooker&ci_src=14110944&ci_sku=B001AQDAFA&ref=tgt_adv_XSG10001
Motor- ??

Could someone tell me what components I will need for this and how to connect them? I will send you a 6-pack of the next beer I brew and I will be extremely grateful. They are outstanding brews by the way!

 

[brewnog]

I've done a bit of homebrewing in my time. Not really convinced that steam heat is the way to go, do you have some more detailed justification than heat being transferred more quickly? I don't really see why it's cheaper either, than, say, an electric immersion element in the bottom of the tub (which would very easily be controlled thermostatically).

 

[nicktay]

Well I want something that transfers heat quickly so that I can do step mashing. I don't know if steam is quick enough, but I thought it would be worth a try.

 

[dlgoff]

I have had a little experience with steam generators used for humidity control in environmental chambers. A PID controller was uses to drive a heating element inside a small tank (approx. 1/2 gal.) which generated the steam as needed. The controllers input was from a sensor in the chamber and was set to maintain the proper set-point humidity.

In your case, you could monitor the temperature of the lauter tun with a thermocouple and control its temperature by turning on a heating element in your steam generator. I would not suggest using a vessel under pressure. Just let the steam mix with the grain.

My question would be, does it matter how much steam can condensate in with the grain?

That'll be one six pack.

 

[dlgoff]

With a little more thought, could you heat the grain by running the steam through a coil of copper tubing inside the lauter tun?

Here is a company that make steam generators:
http://www.reimersinc.com/steam_boilers.htm"
Here is a good place to get temperature equipment technical info:
http://www.omega.com/temperature/Z/zsection.asp"

 

[Q_Goest]

Hi nicktay,
Your controller is overkill, and may not even work as you want it. I’d suggest something much simpler such as a temperature switch with display. Something like this:
http://store.antx.com/digitaltemperatureswitch.aspx

I can’t vouch for this one, I’ve never used it. But it comes with a temperature probe, a relay to drive the valve, and operates on 110VAC. Seems like everything you need in an easy to use package. I’m sure there are others like it, so you may want to look around.

The solenoid valve you pointed at isn’t rated for the temperature. It shows a maximum temperature of only 80 C, so don’t even try to use it. I’d suggest an ASCO solenoid valve that’s rated for hot water and steam such as found here:
http://www.ascovalve.com/Common/PDFFiles/Product/HotWater_SteamR2.pdf

Regarding the pressure cooker, I don’t think you’ll need any additional controls for that. From looking at it, I have to believe it has a built in temperature and pressure control. When you take steam off, the pressure will drop along with the temperature, but because the pressure drops, the water will boil, so you’ll have some additional steam coming off as the pressure drops. That’s a good thing. When the solenoid valve is closed, the pressure cooker will heat back up automatically (I would think!). So I think you’re set with that. No additional controls needed.

Note that the pressure cooker also has to have some kind of pressure regulation/relief device on it. So if the controls on the cooker fail, you have a safety mechanism built in.

Now you’re asking this question on an electrical engineering forum but there’s some thermo and fluid flow you need to be aware of. Pouring that steam into the brew will add roughly 3.6 pounds of water for every kW-hr of heat added. (edit: 3.6 pounds of steam added over an hour's time is the same as a 1 kw heater running for 1 hour) So you may be adding a substantial amount of water to your brew depending on how much heat you need to add and the insulation in your pot. It sounds like you plan on having the water already boiling, so the only heat needed (steam needed) is to make up the evaporation and heat rejected through the walls of your 10 gallon container. If that’s the case, I suspect you'll be ok and there won’t be too much steam (water) added.

Regarding flow rate, the ASCO with a Cv of .34 is plenty big enough. Too big actually. At 15 psi saturated steam from the pressure cooker and ambient pressure in your mixing vat, and assuming 4 ft of copper tube (1/4” copper with .375” OD) on the inlet and outlet, the flow rate is about 18.5 lb/hr of steam. So rather than doing an uncontrolled ‘burst’ of steam (which may actually splash things around a bit) I’d suggest putting a small globe valve on the inlet or outlet of the solenoid valve so you can modulate the flow. You’ll need to adjust the manual valve to suit your needs.

Regarding the stirring device, there are all sorts of mixers available. In industry, they’re also called “agitators” so you may want to Google that as well. Take a look about ¾ of the way down on this page for a mixing device that could be connected to a low speed electric drill and mounted above your pot.
http://www.hobbysilicone.com/supplies.htm

 

[dlgoff]

"When the solenoid valve is closed, the pressure cooker will heat back up automatically (I would think!)."

And blow up if the valve fails.

 

[nicktay]

I like the ideas. Why would the contraption blow if the valve does not close? There's a pressure regulator on the pressure cooker that I thought would take care of that problem.

I think direct injection is the fastest transfer of heat and therefore my best option here. I'm also pretty sure that the pressure cooker is the cheapest way to create steam unless there is an inexpensive system I have not seen already.

One problem I foresee is condensed water in the plumbing which would cause steam to backup and further condense. Is there a way to drain the plumbing of water buildup? If I place the pressure cooker so that the steam and water run downward through the plumbing into the slurry, would that solve my problem? I was thinking about putting a check valve in the plumbing close to the injector so that liquid can't run back through the line.

If this project gets off the ground and finished I will send a six-pack out for your help. Just send me your address. This lauter tun should be more efficient than what is available for purchase and my final beer product will be produced at a much cheaper price. If I have any more problems I will just post them as they come up.

Thanks!

 

[dlgoff]

Why would the contraption blow if the valve does not close? There's a pressure regulator on the pressure cooker that I thought would take care of that problem.

I was thinking you might be taking the steam from the "regulator" port. Is it a weight type regulator? If you are using a solenoid valve, when it's closed, the pressure will build up in the cooker. If the valve for some reason doesn't open, the pressure might increase until the pop-off safety plug pops or the container ruptures. That was my concern.

One problem I foresee is condensed water in the plumbing which would cause steam to backup and further condense. Is there a way to drain the plumbing of water buildup?

What you need is a http://en.wikipedia.org/wiki/Steam_trap" . You can place it just before the lauter tun.

They have a float that rises and falls in relation to condensate level and this usually has a mechanical linkage attached that opens and closes the valve. Mechanical traps operate in direct relationship to condensate levels present in the body of the steam trap.

If this project gets off the ground and finished I will send a six-pack out for your help.

I would really like to have a tast but we work cheap here. Just let us know how it turns out and that's all the thanks we need.

 

[Q_Goest]

Hi nicktay,

Why would the contraption blow if the valve does not close? There's a pressure regulator on the pressure cooker that I thought would take care of that problem.

Let’s be sure no one gets hurt... I’m assuming there is at least one port on your pressure cooker you can tap off of. If that port has a back pressure regulator or other type of pressure relief device, that device must not be blocked from performing its function. If there’s only 1 port, put a T on that port and connect the pressure relief device to one side, and the tubing run to your solenoid valve to the other.

Also, I’m assuming the pressure cooker has automatic controls on pressure and temperature. With both controls and pressure relief, you should be fine.

One problem I foresee is condensed water in the plumbing which would cause steam to backup and further condense. Is there a way to drain the plumbing of water buildup? If I place the pressure cooker so that the steam and water run downward through the plumbing into the slurry, would that solve my problem? I was thinking about putting a check valve in the plumbing close to the injector so that liquid can't run back through the line.

Yes, that should solve the problem. I’d suggest using small diameter tubing, perhaps made of plastic if you find material rated for that temperature. Using plastic reduces thermal mass when compared to copper or stainless which reduces the resulting condensation inside the tube. Also, keep the tubing as short as possible and running downward so any condensate simply pours into the beer.

I disagree you need a steam trap. That’s overkill here. There’s no problem with blowing a few drops of boiling water out the end of the tube and into your brew.

And as for sending out a sample of your brew… I’ll never turn down a hand crafted sample!

 

[nicktay]

Thanks! I will let you know how everything goes and get your address then to send some brews. All the help is appreciated.

 

[nicktay]

I'm a college student, so it will take me some time to save up the funds to purchase all the necessities to do this project.

 

[nicktay]

Still working on accumulating the funds, but I'm out of college and now have a job. I'm excited to start this!

 

[nicktay]

Any tips on where I might find 20-30 gallon food-grade steel cylindrical containers?

 

[dlgoff]

Any tips on where I might find 20-30 gallon food-grade steel cylindrical containers?

I'm getting thirsty just looking at it.
[PLAIN]http://www.machineryandequipment.com/media/catalog/product/cache/1/image/265x/5e06319eda06f020e43594a9c230972d/S/7/S735395.JPG
Here's a place that sells used not only http://www.machineryandequipment.com/view-all-inventory/Kettle/" .

 

[nicktay]

Thanks dlgoff! I have some good options on that end now.

I've been giving this some thinking, and I was wondering if anyone know of a usb peripheral I could use that would collect data from an electronic thermometer and control power distribution?

i'm thinking that there has to be some sort of switchboard out there that you can use to send data to your computer (in my case a mac) while running software that can record the data and simultaneously turn on and off solenoids, a steam generator, a motorized stirrer, pumps, etc. This way I could collect and store measurements for each brew and automate the equipment based on parameters or timers.

Thanks for all the input!

 

[dlgoff]

nicktay,

Now your talking. With good control comes good beer. You can tweak the system for your own taste. Anyway, sounds like a fun project.

I don't know how much money you are willing to spend, but http://www.ni.com/labview/" .

LabVIEW (short for Laboratory Virtual Instrumentation Engineering Workbench) is a platform and development environment for a visual programming language from National Instruments. The graphical language is named "G". Originally released for the Apple Macintosh in 1986, LabVIEW is commonly used for data acquisition, instrument control, and industrial automation on a variety of platforms including Microsoft Windows, various flavors of UNIX, Linux, and Mac OS X. The latest version of LabVIEW is version LabVIEW 2009, released in August 2009.

http://en.wikipedia.org/wiki/LabVIEW"

There are other ways also. I designed a generic system using a smart modem (16 digital IO, 8 analog inputs, 4 analog outputs, 2 accumulator inputs) that interfaced to a serial port (RS232). I first learn the modems uP commands (in order to read switch status, switch relays, measure values, etc.) then I wrote and complied a BASIC program to provide a personal computer MMI (man machine interface). Then it was just a matter of choosing the right sensors for measuring, relays to turn on pumps and operate solenoid valves, and transducers (4-20ma output) to operate control valves etc.

 

[nicktay]

Wow, that is absolutely perfect for this project. I wasn't planning to spend too much on the control end originally, but I think that is going to change.

I'm not an engineer, however, so this is a little foreign to me. I'm sure with a little research I will be able to figure things out, but I would like to know which device to use. Would this work?:

http://sine.ni.com/nips/cds/view/p/lang/en/nid/201630#

Also, how are the device and instruments, valves connected? Does the DAQ device connect directly to the solenoids and the temperature probe?

Also, temperature being my number one concern, are there any suggestions you might have on how to take advantage of a DAQ? It seems like there are so many more possibilities incorporating this into my project.

Also, I'm thinking about employing manufactured sparging nozzles (http://www.s-k.com/pages/pro_04_04.html) instead of making my own. For the life of me I can't find an industrial parts retailer who sells the parts I will need. I am hoping that using manufactured parts will help me avoid too much cleaning and clogging.

With sparging nozzles, I am a bit lost on a few factors:

1) psi's required
2) Number of nozzles
3) Which configuration to use (as there are a few: a. http://www.s-k.com/pages/pro_04_04_app1.html; b. http://www.s-k.com/pages/pro_04_04_app2.html; c. http://www.s-k.com/pages/pro_04_04_app3.html).

Also, would an electric pressure cooker work now? I am amping up the size to about 20 to 30 gallons as opposed to 5-10 gallons, so I think I will have to construct my own steam boiler. I would need to fit a closed high pressure container with a heating element, a pressure release valve, and a pressure probe for the DAQ along with outlets. Does this make sense, or is there an easier way to do this?

Thanks again dlgoff! Hope to hear back!

 

[hamster143]

You don't really need all that fancy electronics for the task at hand. It'll be convenient, for sure, but you can do all-grain with a much simpler setup. Indeed, beer has been brewn long before the invention of solid state electronics.

I have a homemade lauter tun that cost me around $40 in parts. It consists of a 5-gallon Igloo cooler from Wal-Mart, a simple sparging assembly made of copper tubing with some small transverse holes, and a faucet. The hardest part was to seal all leaks. Step mashing is done by adding measured quantities of water that you boil on the range top. The cooler is sufficiently well insulated for brewing purposes (the mash might cool from 70 C to 68 C in 30 minutes).

 

[dlgoff]

Wow, that is absolutely perfect for this project. I wasn't planning to spend too much on the control end originally, but I think that is going to change.

I'm not an engineer, however, so this is a little foreign to me. I'm sure with a little research I will be able to figure things out, but I would like to know which device to use. Would this work?:

http://sine.ni.com/nips/cds/view/p/lang/en/nid/201630#

This digital I/O would work fine for inputting switch statuses (open/closed→I) and closing switches (open/close a relay→O), but not analog signals like temperature. Note, you need the software also and the inputs are expecting 5volt signals. You would have to provide the proper resistors and their data sheet doesn't say how much current the outputs can supply. So I don't think you would be able to drive a solenoid valve directly but maybe with a small relay.

Also, how are the device and instruments, valves connected? Does the DAQ device connect directly to the solenoids and the temperature probe?

Also, temperature being my number one concern, are there any suggestions you might have on how to take advantage of a DAQ? It seems like there are so many more possibilities incorporating this into my project.

As above, solenoid valves would need to be driven by a relay since most outputs from a DAQ are small current sources. For the temperature, you're going to have to have an analog I/O like this one.
http://sine.ni.com/ds/app/doc/p/id/ds-218/lang/en"
I would suggest using a thermocouple with a transducer to provide an analog output to the DAQ. And you would be able to control the temperature with the outputs. Here again you will have to determine what type of driver to use between the output point and the heating device. Maybe a solid state relay SSR.

All this being said, hamster143 has a good point. You can do it all manually. But if you are trying to learn control system interfacing, this is a good project.

 

[nicktay]

You don't really need all that fancy electronics for the task at hand. It'll be convenient, for sure, but you can do all-grain with a much simpler setup. Indeed, beer has been brewn long before the invention of solid state electronics.

I have a homemade lauter tun that cost me around $40 in parts. It consists of a 5-gallon Igloo cooler from Wal-Mart, a simple sparging assembly made of copper tubing with some small transverse holes, and a faucet. The hardest part was to seal all leaks. Step mashing is done by adding measured quantities of water that you boil on the range top. The cooler is sufficiently well insulated for brewing purposes (the mash might cool from 70 C to 68 C in 30 minutes).

What started as a fun little project has kind of changed course for me. I'm considering starting a nanobrewery and would like to have process and quality control. In the very least I will be able to get my name out there.

What I really want is to control mash temperature very well to reach consistently high mash efficiency. I think a wort chiller is key here too in clarifying and in preventing infections.

 

[nicktay]

This digital I/O would work fine for inputting switch statuses (open/closed→I) and closing switches (open/close a relay→O), but not analog signals like temperature. Note, you need the software also and the inputs are expecting 5volt signals. You would have to provide the proper resistors and their data sheet doesn't say how much current the outputs can supply. So I don't think you would be able to drive a solenoid valve directly but maybe with a small relay.


As above, solenoid valves would need to be driven by a relay since most outputs from a DAQ are small current sources. For the temperature, you're going to have to have an analog I/O like this one.
http://sine.ni.com/ds/app/doc/p/id/ds-218/lang/en"
I would suggest using a thermocouple with a transducer to provide an analog output to the DAQ. And you would be able to control the temperature with the outputs. Here again you will have to determine what type of driver to use between the output point and the heating device. Maybe a solid state relay SSR.

All this being said, hamster143 has a good point. You can do it all manually. But if you are trying to learn control system interfacing, this is a good project.

Thanks for the input here, I think this will be a lot of fun, my absolute dream for me. I've still got a lot of specifics that I need to hammer out though.

 

[nicktay]

Hi Everyone,

Thank you for helping me in this thread. It's been a long time, and I still haven't materialized this idea, but I still want to move forward. I am currently working on pulling together a team to make this happen. I may have a computer programmer and a salesperson, but I would still be interested to know if anyone in industrial production and engineering would be interested in joining me. Location doesn't have to be a problem, either.

Thanks for your time,
Nick

 

[dlgoff]

Hi Everyone,

Thank you for helping me in this thread. It's been a long time, and I still haven't materialized this idea, but I still want to move forward. I am currently working on pulling together a team to make this happen. I may have a computer programmer and a salesperson, but I would still be interested to know if anyone in industrial production and engineering would be interested in joining me. Location doesn't have to be a problem, either.

Thanks for your time,
Nick

Welcome back. I could help with process control etc. but may I suggest that you take a look at this https://www.physicsforums.com/showthread.php?t=468902" thread. There are members there with lots of brewing experience.

Regards

 

[nicktay]

Great! Thanks for your very quick response! You've been really helpful, and this forum has been great. I will definitely get back to you soon with some more info and questions. Thanks for the site reference.

 

[nicktay]

Hi again,

I'm estimating costs to create financial models for my business plans, but not having engineers on my team makes it difficult to do this. I know that a lot fo the sensory equipment will add up quickly and my cost will entirely depend on the sophistication. I just decided that the capacity of the new system should be about 7 barrels (217 gallons/8.2 hectolitres) in order for it to be small enough yet still cost efficient. Would someone be able to venture a guess at how much it would cost in materials to build the computer control system? The idea is to have a control panel for each of the pieces of equipment: the steam generator, the lauter tun, the grant (for transfer of the beer from the lauter tun to the kettle) and the cooling system. All the panels will be linked to a main computer board and linked to the web with a web interface so I can monitor and control via the web. I have talked with some computer engineers so I know this can be done, I'm just don't have the slightest clue how much it would cost for the hardware. Also, I'm not sure the size of steam generator this project will require. Anyone have an idea? I will have to heat the water to 120 to approximately 212ºF. Thank you so much for your help thus far!

 

[jim hardy]

if this is a shoestring operation

i'd see what you can do with commercial parts and hobbyist strength microcontroller..

solenoid valves from washing machines and refrigerators are way less expensive than the industrial one I'm accustomed to, and surely icemaker water valves are certified for food. You can order them from Sears.

see what hobbyist controllers are out there. i used Micromint Dominoes because they're ridiculously easy to program (Basic and load from your PC) and Answerman for input.. Almost zero development time and canned control programs at their site..
your electronics guy will have his own favorite. ask him .

good luck on your startup.

 

[nicktay]

Wow, thanks for the quick and very helpful reply!

 

[nicktay]

Hi again,

As I pointed out, I'm starting to do financial modeling and I'm trying to figure out what size of a steam generator I will need for a 1 barrel, 3.5 barrel, and 7 barrel system. What I would like is to have the steam agitate the liquid with enough force that I do not need a mechanical agitator. Therefore, I'm not really sure what type or generator I need. I know there is wet and dry steam, saturated and super heated steam. Does any of this matter to me when I pick out a steam generator? Do I need superheated steam? I don't want to destroy the enzymes, so if I use superheated steam it may destroy them I think. Also, when looking at steam generators, what should I be looking for at each brewhouse capacity I have listed above? Is there a quick rule of thumb (ie so many mbu's?, or so many kilowatts)?

 

[dlgoff]

Hi again,

As I pointed out, I'm starting to do financial modeling and I'm trying to figure out what size of a steam generator I will need for a 1 barrel, 3.5 barrel, and 7 barrel system. What I would like is to have the steam agitate the liquid with enough force that I do not need a mechanical agitator. Therefore, I'm not really sure what type or generator I need. I know there is wet and dry steam, saturated and super heated steam. Does any of this matter to me when I pick out a steam generator? Do I need superheated steam? I don't want to destroy the enzymes, so if I use superheated steam it may destroy them I think. Also, when looking at steam generators, what should I be looking for at each brewhouse capacity I have listed above? Is there a quick rule of thumb (ie so many mbu's?, or so many kilowatts)?

In my opinion, if you are comfortable with adding water from the steam condensate as pointed out in post #6 by Q_Goest,

Pouring that steam into the brew will add roughly 3.6 pounds of water for every kW-hr of heat added. (edit: 3.6 pounds of steam added over an hour's time is the same as a 1 kw heater running for 1 hour) So you may be adding a substantial amount of water to your brew depending on how much heat you need to add and the insulation in your pot.

you should go for "overkill" and allow the controller to throttle the steam generator down. i.e. only using the necessary watts to accomplish you heating needs.