Mash Temp Control

[LandoLando]

Hi, this is my first post. I've been brewing for about 5 years now.

I have a 14 gallon kettle with a valve on the bottom. I also have a 8500 BTU/hr heating element from a hot tub. I want to install the heating element inline with a Brau inline pump and control the temp with a thermistor, 50A solid state relay, and Arduino microcontroller. The plan is to bring the mash water within 5 F of mash temp and then run the pump and heater to control the temp. Add the grain once the mash water is at the appropriate temp and let her rip.

Any concerns?

Are the Bräu pumps quality?

If i have a constant whirlpool can i trust that the temp is uniform throughout the mash?

Any one do multiple step infusions with a similar setup?

 

[logdrum]

Check out the electric brewing forum, great info & lots of helpful folks. I'm going a very similar route myself.

 

[GoeHaarden]

If I'm reading this correctly, it sounds like you're wanting to do a RIMS setup with arduino as a controller!? I've actually been working on a similar system, and did my maiden voyage the other week which went fairly well. Here are a few lessons I learned while researching/building my own.

- Get a stainless steel heating element if it will be in contact with anything you consume. Most elements are advertised as SS but the end nut is not and will rust. I use the 2000w/120v SS element from brewhardware and on all the test runs I did it brought the water temp up from ~70 to ~160 in about 20 minutes. This particular element pulls about 17 amps.

- I use a chugger pump...constant recirc

- My RIMS tube is about 11'' in length total with a thermowell at the opposite end of the element (~1'' between the two). I read a temp there and in the false bottom drainage tube (6'' thermowell). The temps stay fairly close to each other (within 1.5F when heating), and will level out when I stop raising the temp.

- A lot of people use PID algorithms to control their temps, but what I noticed from all my testing and my last batch is that I didn't get much overshoot. Since the element is essentially rinsed will slightly cooler fluid it will equalize fairly quick once you stop heating. So, I scrapped the PID and reprogrammed the arduino with a simple greater than/less than function. Besides being a royal PITA, I didn't have great success with tuning the PID either.

- I used a 30AMP arduino relay from ebay for like $3.

- I use 2x DS18B20 one-wire thermometers. Supposed to be accurate to +/-0.5C. Plus easy to implement with arduino.

Its still in the testing phase, but for a first run it did exceptionally well at holding the temp where I wanted. The new code that I wrote allows for a timed step mash with the ability to do 3 steps. I'm going to do some more testing this week to see how the stepping feature does. I don't see why stepping up the temp would add any complications if you don't get dramatic overshoots.

My setup is always changing, but I think once I get this dialed in I will be real happy with it. My knowledge base is pretty limited with all of this, but if you have any specific questions I'd be happy to help.