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How temperature stable is the new Breville Dual Boiler? Would you believe more temperature stable than even a La Marzocco GS/3? I'm not kidding. I had to type out these numbers for an email I sent, so I'll repeat them here. From my Sunday testing session o the Breville Dual Boiler:


Recovery tests:
Pull 25 second shot; pause 30 seconds between shots, measure temperature at 15 second point for each shot. Remove the scace'd portafilter between each shots. Do test for five shot pulls. Programmed machine temperature is 201F. Remove portafilter (with scace) from the grouphead between shots.

Measured Temperatures: 1) 201.7F; 2) 201.4F; 3) 201.4F; 4) 201.1F; 5) 201.4F.

Average Shot Temperature Test
Measuring the temperature average across a 25 second shot, starting measurement at 10 seconds in.

Test parameters: insert Scace'd portafilter, starting temperature above 175F for each measurement test (the PF comes up to temperature quick in a fully hot groupehad). 25 second shot pull. Programmed machine temperature is 201F. Commence Fluke temperature measuring at 10 seconds in, hold (on fluke) at 25 seconds. Pause of about 2 minutes between measurements. Record average, minimum and maximum temperatures for each shot pull between 10-25 seconds.

Test 1: Avg: 200.5F; Min: 199.6F, Max: 201.2F
Test 2: Avg: 201.2F; Min: 199.8F, Max: 201.8F
Test 3: Avg: 200.7F; Min: 199.7F, Max: 201.4F
Test 4: Avg: 200.6F; Min: 199.5F, Max: 201.0F* (held 201 for at least 7 seconds)
Test 5: Avg: 201.1F; Min: 200.0F, Max: 201.5F

Bottom line - this Breville Dual Boiler is really stable - actually a bit more stable than the GS/3 tests I ran some time ago. I blame this success on the Breville's PID controlled grouphead thermostat.
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4 comments
 
Mark, any plans to quantify the stability over a variable workload (i.e., more randomized shot-making pace)? Did you do any pre-shot flushing or flushing for the walkup?

In any case, the dataset is pretty impressive. The remaining question would be, how is the espresso? Are the shots good, and across what range of espresso styles? For example, how well can it handle more traditional stuff like Klatch Belle, Stumptown Hairbender, and on the other side, how does it handle things like Intelligentsia Fruit Bat, CCC Apollo, and bright, high-quality SOs that often prove much more challenging to work with on cheaper machines?
ted m
 
Hi Mark, great testing data! I've left a msg. for a Breville engr., but I am not sure there is a full pid (w/sensor) in the grouphead. I know there is a controlled 100W / 200W heating element, but it is not clear how the boiler pid knows to turn this on or off. We know for sure that if there is a sensor/PID in the gh, that it is not user accessible. Let me know if you hear further. Thanks!
 
WoW, that's absolutely unreal Mark!! I can't wait till some Coffeegeek member/owners start to post thrie thoughts in the CG forums. It'll all take time as the machine is so new. Cheers!
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