OT....liquid temp control

Hello all,
A friend of mine is into brewing beer and was asking me about a way to control the temperature of a boiling liquid. What we are looking for is suggestion on ways to do this. I know there will be a trade off for accuracy vs. cost, but this is a hobby project. I need some ideas of components to use. I figured a AD PLC would fit due to low cost, but beyond that I am not sure where to look....

Thanks,
Micheal

This is probably a foolish question but...

Isn't the temperature of a boiling liquid kind of self-regulating?

Keith

All I know is depending on what he is making depends on what the temp needs to be.....for example the set point would be 160 deg F, plus or minus 5 deg.........

If just temperature control then a stand alone controller might work for you. See link below for one option.

http://web2.automationdirect.com/adc/Shopping/Catalog/Process_Controls

My brother makes beer also. I do not recall if he boils, but of course does heat. A pure material will have only one boil point, if a mixture the boil point will vary with concentrations of the mixture components. This is more of a distillation situation with its own set of challenges and temp control is critical here.

For just heating a good temperature controller should be all that is needed. To keep price of controller down I would use two stage control say 90 and 10%. Use 100% heat to bring close to setpoint (say 5 degree less) and turn off the 90 and heat rest of way with 10%. OR heat to SP with 100% and then turn off 90 and let the 10% just meet ******t (A M B I E N T)loss.

Dan Bentler

Believe it or not, I looked this up last week. The common solution for home brewers are simple temperature switches from LOVE Controls. They control gas to LP gas through combustion rated ASCO valves.

If I'm guessing right, you need two temp switches and two valves. The switches have a nice digital display and run about $60. The valves run around $250. Try http://www.alenuts.com/brutus.htm to see one mans solution.

I would be cautious with this approach. LP is dangerous stuff. Still there more than a few people using this set up.

Oh yeah, you don't want to boil the wort. This is not a still. The heat simply accelerates the normal process, and kills some bad bugs.


Any liquid will have a self regulated boiling point. Alcohol boils somewhere around 180 F. I would bet you do not want to boil off the good stuff. ;D

I do some homebrewing and have been kicking this same idea around for a couple of years. It can be a pain trying to maintain 155 degrees F, +/- 10 degrees with a King cooker after you've had a few beers.

The path I'm going with my solution is to use a surplus temperature control with a fairly generic gas valve, say off of an old water heater. The gas valve is an on/off with a standing pilot and uses a thermopile to generate its own operating voltage. That way, if you're, lets say incapacitated and the pilot goes out, you're valve will shut off.

If you choose a valve thats set up for propane, or can be converted to propane, then everything would be portable with the only the temperature controller needing to be plugged up.

While I don't have this thing in operation yet, I have started gathering the parts. The King cooker, temperature controller, gas valve, and thermopile I already have. I still need to get a thermocouple (easy, cheap), a natural gas to propane conversion kit, and a good regulator. The valve and thermopile came off of ebay for about $40. The controller was no longer needed at work so I picked it up for free.

This is my solution. I'm sure theres other ways of going about it, but for my setup, I thought this would be the best for me.

Hope it helps.

Any liquid will have a self regulated boiling point.

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I am sure that you meant "if the liquid is in an open vessel".

Otherwise, both temperature and pressure can increase to the danger point.

Lancie1 said:

I am sure that you meant "if the liquid is in an open vessel".

Otherwise, both temperature and pressure can increase to the danger point.

Click to expand...

Of course. As long as say alcohol is present, the boiling point of the alcohol will regulate the temp, as soon as the alcohol has boiled off, the next lower boiling point will take over, and the temperature will increase to that point.

Enclose the vessel, and the pressure high or low will alter the boiling point.

I have a couple labs based on this. Lots of fun.

plchacker said:

Of course. As long as say alcohol is present

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At this stage of the beer making process,theres no alcohol present, mainly just sugars, waters, and some solids.

There normally is no need to control the boil in a boil kettle. It simply boils, end of story. The only thing you do need to maintain is the boil rate, which is simply set by adjusting the regulartor on your boil kettles burner. Boil rate effects your evaporation rate, but it can also effect the maltiness of a beer by carmelizing / not carmelizing different malt products and color via [size=-1]Maillard reactions[/size].

Now if he is talking about maintaining temps in a mash tun during the mash process, that is a different story. There are many ways to go about it, depending on his setup. I use what is called a hearms system, or a heat exchanger automated recirculating mash. If this is what he is looking to do, ill be more than happy to help you out. Let me know. Thanks.

matt

To clarify, I ment to control mash temp, not that if he just wants to do a hearms. Sorry if that was confusing.

jrexrode said:

At this stage of the beer making process,theres no alcohol present, mainly just sugars, waters, and some solids.

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Thats nice to know. I am not a brewer. I was just discussing boiling points of liquids.

Thanks for all the information guys. I will look into the options presented and the pass on the information. I will see the setup this or next weekend and I think it will give me a better idea of what is wanted.

Thanks,
Micheal