So, after reading the newbies section of the Home Barista I decided to run a temperature analysis on my Breville Barista Express BES870XL. I'm not entirely sure what to make of the results and so I thought I would post them and see what other people have to say....
I used a digital food probe inserted in the portafilter immediately under the basket to take temperature readings.
_at 5min after switching on the machine I pulled a shot (with coffee): temperature reading 73.4°C
Switched off machine for an hour.
_at 5min after switching on the machine I flushed the group and portafilter, THEN I pulled a shot (with coffee): temperature reading 82°C
Left puck in group head!
_at 10min, discarded puck, wiped clean portafilter, flushed group only, pulled a shot (with coffee): temperature reading 85°C
_at 20min repeated as above: temperature reading 85.4°C
_at 28min repeated as above: temperature reading 85.4°C
This time I discarded the puck after last shot.
_at 35min wiped clean portafilter, flushed group only, pulled a shot (with coffee): temperature reading 85.7°C
I discarded the puck, removed basket and took reading inside portafilter (with no coffee) at 40min: temperature reading 90.5°C