NottmSteve wrote:Do I need a pobe installing and some electrical gubbins? So many people are showing / comparing / creating the charts that I guess it must be easy?
You do not have to install electrical gubbins as long as you are willing to take readings of the temperature each minute as Bruce suggests.
Some people do add such gubbins and you will see much discussion of bean mass temperature and environment temperature. I do not disagree with anything Bruce says above but I find that, in practice when using a consistent bean mass, the Hottop temperature readings are representative enough to allow you to predict when first crack will start/end and, therefore, when heater power should be adjusted.
I think that it is invaluable to take readings when learning to roast. Being constantly by the roaster watching listening and smelling what is happening. I would recommend comparing your roast profile with a previous good roast as it progresses. You can do this by just plotting the temperature on a graph which has a known good previous roast plotted on it or by using suitable software, spreadsheet, roast logger or the Coffee Roast Database.
If you wish to add additional temperature probes there are many digital multimeters that will measure temperature. Some have serial or usb interfaces to allow readings to be transferred to a computer. The software required to log the data is generally suitable for a specific multimeter only and usually only Windows OS.
I have been playing with a way to automatically log temperature readings from my Hottop (or just about any other LCD or LED digital display) without any electrical connection to the roaster (or digital display) and at no cost. This started as a joke and a bit of a bet with my Son but I am astonished that it is working well for me and I use it to log and chart all my roasts but I do not know if it would be suitable for others to use. The following is a screen shot of it running showing a current roast profile against a selected template profile.