Magnetically stirred coffee seems to be a success, but still tuning the  parameters.  I have a surplus temperature control module connected to a  thermocouple probe to monitor the temperature.
My first attempt was confounded by not programming the controller to read a  K-type thermocouple, it came set for a J-type and so the water never got  over 88C even boiling…  which it did for a while and that’s not good.  Not good at all.
Today I let the water temp get up to 80C and the coffee was very good,  smooth and not bitter at all.  Perhaps a bit too smooth, a bit like the  cold-brew taste but warm and much faster thanks to the stirring action.  I  will try 90C tomorrow and if success continues, modify the hotplate to add  a direct thermal element bypass to the outside so the temp controller can  control the heater directly (now I just watch and turn off the heater at  the target temp.)
The theory is that by continuously stirring the coffee, a lot of flavor is  extracted without relying on heat, and that the stirring also ensures  uniform heating through the entire volume and thus the temperature can be  set fairly precisely (to about a degree C, +/- 1 degree or so) to optimize  differential extraction of the organics in the grounds.  
Coffee Science Update
	Wednesday, March 18, 2009 
Posted at 16:00:26 GMT-0700

Leave a Reply
You must be logged in to post a comment.