After thoroughly checking over the machine, I decided to try a seasoning roast of 1 pound (450g). Machine was at 70°F (21.1°C), I took it outside into the cold and dark, and immediately started the warmup.
Ambient 28°F (-2.2°C), 80% RH. Preheated to 446°F (230°C).
Preheated for 25 minutes before the machine said it was ready. I let it go for 10 more minutes.
Started the roast. Drum at D9, heat at P7, fan at F4. Took 6:30 to first crack, ROR around 20-22 the whole time once it stabilized from the beginning. Adjusted to P5 and F5 and took it through second crack (9:30; I purposely spread this out), finishing it at 466°F ITBS temp (241°C).
Finally, I dropped power to P0, upped the fan to F9, and let the beans agitate until ITBS had dropped to about 375°F (191°C). Then, I initiated the cooling cycle and dropped the beans.
At that point, I thought, “What the heck?” and hit F1 to start preheat for a back-to-back roast. Wound up doing 3 roasts (all 1 pound) back-to-back.
The only thing that really changed from one to the other was time to first crack dropped to 6:15 by the 3rd roast, second crack coming at 9:15. It also warmed up slightly outside to 31°F (-0.6°C).
My BIG takeaway here? I don’t think I’ll be having too much trouble using this machine to roast in the cold.
Some Bullet roasters have noted that their roast recipes and playbacks produce different resulting profiles when the ambient temperature is different and you may have to adjust your roast as the ambient temperature changes.
During the summer months, you may notice that the PCboard temp gets hot enough to force the Bullet into a cooldown mode in the middle of a roast. A number of us have added an external fan blowing at the belly of the Bullet to keep the shutdown from happening. Aillo has made modifications to the firmware updates to address this issue. There are a number of threads on the forum about this.
Fortunately, because of the inductive drum heating, the Bullet moves far les outside air than most roasters, so, while outside air temp will affect your power/time to milestones (and time to preheat), it doesn’t have as much affect as with many other kinds of roasters.
Grey- I’m certainly open to being shown that I am wrong but I disagree with your comment.
I’m under the opinion that airflow is controlled by the fan independent of the heating source be it inductive or gas flame. In many gas roasters, the air is directed through the flame to preheat ambient external air. In the bullet, fan and airflow is cooling and moving outside air is a function of fan speed… The colder the external roasting environment, the more effect on a profile.
Thanks for the info! I’ve been reading a whole lot here while I was waiting for my roaster, so I am aware of that potential issue. For me, it probably won’t be a problem, as in the summer here, I will usually roast late in the evening after it has cooled off. Typically I won’t be roasting in temps above 80°F (27°C)at the absolute highest. More like 65°-75°F (18°-24°C).
My anecdotal observation since I live in New England but I roast inside the house with a kitchen window cracked open every time regardless of outside temp when. After roasting for about 2 yrs on the Bullet I can say that the pre-heat and the roasting time is a little bit quicker in the summer. The PCB board also heats up higher in the summer as @billc pointed out. If it hits 90F outside I won’t roast even inside (cracking open that window messes with my A/C thermostat). I haven’t figured out what factor humidity plays since I haven’t bought the thingy to monitor it.
