Temperature probe location on a RIMS

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

atoughram

Well-Known Member
Joined
May 23, 2013
Messages
1,896
Reaction score
297
Location
Puyallup
I'm planning on upgrading my RIMS tube sometime after the first of the year along with a few other brewery upgrades. I noticed on Bobby's RIMS tube that there is a location at the end of the tube for the PID Temp probe.

When I built my RIMS ten years ago, I welded a bung in the side of my MLT about midway up (It's a Sankey Keg), and installed the probe there. My reasoning is that if I want the mash to be a certain temperature, I probably ought to measure it at the mash, not at the outlet of the MLT nor the end of the RIMS tube.

Fast forward ten years. I've noticed that without stirring the mash, I get stratification, the probe will be at mash temperatures but the thermometer in the outlet of the MLT will read lower by up to five degrees. It equalizes but the enzymes dont wait and the wort can be somewhat different than I intended. When I brew smaller beers, the probe level is constant, so the probe is closer to the top of the grain bed, another problem. I've often thought about putting a stirrer in, a stainless paint stirrer on a 1/2" drill motor and running that but I'm not sure if it's worth it in the long run. When I upgraded to the Auber PID (SYL-2362 iirc), I did an autotune but on the last batch, it overshot quite a bit which tells me I need to change the system somehow.

My question is, how was it determined to put the temp probe in the outlet of the RIMS tube? How long does it take to equalize temps (The grain bed is at ~ equal temps throughout and the outlet of the RIMS is approximately the temp of the outlet of the MLT). Is it better to have the probe in the end of the RIMS? or elsewhere? In the plating shops I've worked at, we measured tank temps in the tank but those tanks were 10,000 gallons + and we're talking about 10 gallons here.

I'd like to have better control of my mash temps and could fiddle with the PID parameters but I dont want to reinvent the wheel either.
 
You have the right idea that measuring the bulk of the mash as an average would be ideal but you can only put the probe in a fixed location. If you constantly stirred the mash, any probe location WOULD represent the average mash temp. Without stirring the mash, having the probe sit in a pocket of colder mash, say where nearby channeling is keeping that pocket cold, the controller may leave the element on full time and denature enzymes well before the cold pocket caught up.

The probe being inside the main heating chamber ensures that you don't grossly overheat and in the case of pump failure, loss of prime, or stuck runoff, it makes sure you don't boil the wort in the tube. If you find that your given system's thick mash is always 3F lower than the RIMS output, then you now know you need a +3 setpoint. There are pros and cons to every way to do it.

Not that this is any profound revelation, but the liquid flowing over the element in the RIMS tube IS "the mash" and you have to think of the whole body of liquid as such, not just the thick part in the mash tun. ;-)
 
Thanks for the reply Bobby, I know some thought must have been taken to place the probe in the RIMS tube, so I was curious why..

One nice thing about it there is that I wouldn't have to remove the probe every time I brew..
 
I was going to mount mine at the output of the MLT but I think based on the info that I'll go with the outlet of the RIMS tube. I can always change it but it makes sense.
 
I was going to mount mine at the output of the MLT but I think based on the info that I'll go with the outlet of the RIMS tube. I can always change it but it makes sense.

When I upgrade my RIMS Tube I'll move it and see how it works! Full report at 10! :mug:
 

Latest posts

Back
Top