Hi everyone, This is probably in the wrong place, so if I'm out of order please remove or move as you think fit.

I would say a new thread would be better than trying to piggy-back on this one.

 

Maybe a BeagleBone Black with a few external components will do the job?
The BeagleBone Black is a very cheap (£36 from Farnell) and good Linux based embedded computer. Using the board you could write software to read temperature probes and control your refrigeration gear. To take it even further, you can monitor & control the device from over the internet. Not bad for £36 and a bit of time learning software.

The BeagleBone Black has some great, quick and easy reading books to help you get started writing software in no time at all. See these on Amazon:
http://www.amazon.co.uk/Programming-BeagleBone-Black-JavaScript-BoneScript-ebook/dp/B00J4XLILE/ref=sr_1_1?s=books&ie=UTF8&qid=1411432599&sr=1-1&keywords=beaglebone black
http://www.amazon.co.uk/BeagleBone-Black-Projects-Evil-Genius/dp/0071839283/ref=sr_1_2?s=books&ie=UTF8&qid=1411432599&sr=1-2&keywords=beaglebone black

I'm actually working on my own project using the BeagleBone Black RevC and have read both of the above books.

So why have I recommended the BeagleBone Black as an option? Because someone else has already started making something similar! Not quite sure to what scale this guy is trying to achieve compared to you.
Anyway, here's a YouTube video about it

To find out more information about the BeagleBone Black Linux Computer click this link http://beagleboard.org/black

One the other hand, if you need this done quickly and less "Home-Made", then maybe this isn't an option for you.

I hope this helps and good luck!

 

... or maybe this Automated Brewing Forum can help you http://www.homebrewtalk.com/f235/

A few more Links:

RaspberryPi Brew: http://www.brewpi.com/

BrewTroller: https://www.oscsys.com/projects/brewtroller

Electric Brewing: http://www.ebrewsupply.com/?SID=6e99f4302ccb55af6a6bb88679cb9dc0

 

Really? A Linux computer and a programming project as an answer to a question about operating a thermostat?