Bullet suitability for dark roasts

Hello friends!

I am looking at possibly getting a Bullet, but before I take the plunge I have a few questions for the experts here. I’ve been roasting for over a decade on a Gene Cafe roaster, which is simple and does the job, but I’m looking for something to be able to do larger roasts, more often, with better repeatability.

  1. I generally prefer dark roasts. Yes I know, it’s not the style these days, but I know what I like :laughing: . I roast into 2C, in the FC+ to Vienna range, and was hoping to get some subjective thoughts from anyone with a Bullet on how appropriate it is for roasting into this range. Do you get results you’re happy with? How long does a roast into this range tend to take?
  2. Dark roasts result in a lot of oil accumulation, what does the cleaning regimen look like if you roast to this range?
  3. Dark roasts result in a lot of smoke, so right now I roast outdoors. This gives pretty mediocre results in the winter, as I live in a cool environment (Vancouver BC – winter days often top out at around 5C/40F). Is roasting at this ambient temperature on a bullet a complete no-go? I do have a garage I can roast in, which would be protected from the elements but it is unheated and will still be close to the outdoor ambient temperature.

Thanks everyone!

I’ve roasted outdoors in the winter but that’s in southeast Arizona… 15 °C maybe? I’m no expert but here’s my take.

Re: 1… There’s no issue. I roast into 2C on essentially all roasts.

Re: 2… You’ll have to clean more frequently. On the order of 15-20 batches of 550 gm for me. You’ll have to pay attention to the IBTS (the IR temp measurement), though a recent f/w change seems to help that a lot.

Re: 3… Outdoors in BC in the winter? You are a hardy soul! That ambient will definitely affect roast time & resultantly the profile… probably drag out the end of the roast (which can be a good thing depending on the beans).


I have been roasting dark on my Bullet since I got it in 2015 (my serial number is 75), and it has been splendid in every iteration – I’m now at V2. I get all my beans from Sweet Maria’s, take their advice on which beans are good for espresso. I roast dark for both regular and decaf, usually into the first few snaps of 2nd crack but the Bullet will easily go farther if I let it.

I do need to clean a little more often than if I roasted light, I think.

But perhaps most important to you is that the Bullet does not like low ambient temperatures. I roast in my garage and if the Bullet senses less than 55F or so it won’t preheat. So I keep a heater close to the Bullet and run it until the roaster will start.

Thanks to both of you, this is very helpful!

@djmsalem I am curious about your heater setup – I could definitely set up a heater in my garage but I assumed it wouldn’t do the trick. How cold does it get in the space that you roast in? Is the space indoors or insulated? What kind of heater do you use?

It’s just your basic electric space heater, which I have set up on a table close to the roaster. I have an enclosed but (obviously) unheated two-car garage and it took the temperature in the space from 52 to 55 degrees in less than an hour. But I think having the warm air blowing directly on the Bullet probably helped more than anything.

I am fortunate that I have a Quest M3 roaster as a backup, from before I had the Bullet. It is totally manual with no electronics. I also have a Gene, from before I had the Quest.

So here is my sincere advice: By all means, get the Bullet if you can afford it, even if you can only roast in it nine or 10 months of the year, and keep the Gene in good order for winter. The Bullet has given me an extraordinary amount of pleasure and has been my very flexible partner as I have tried to learn the nuances of roasting large batches. I got it at the very beginning and it is one of the best purchases of any kind I ever made.

Thanks! This is all very helpful advice, I appreciate it.

At the risk of stating the obvious, if you do run a space heater next to your Bullet, you’ve got two ~1500W appliances each wanting to draw about 12-13A of current (at 110V), so plan accordingly.

Absolutely true, and I don’t run the heater and the Bullet at the same time!

Thanks for the reminder! In my case, my garage happens to be wildly over-serviced, I’m pretty sure I could run both the roaster and heater at the same time but I’ll run the numbers before committing myself.

Perhaps investing in a used salamander style propane-fired construction heater might be useful. You can get a lot more heat into a space very quickly with propane than you can with electricity.

Ambient temp will have a very big effect on the roasting profile, which means that if you’re roasting at a lot of different ambients, you will be constantly chasing the roast. If you can warm the space to the same temp every time, then your roasts will be much better behaved.

Alternatively, if the space allows, build a smallish compartment around the roasting station bug enough for you and the roaster - much less volume to heat. The compartment could have hinged walls/ceiling so that it could be collapsed between roasts, if you have to fit a car in there.


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@matt.adam Just my 2 cents - I also recommend that when you’re not roasting to store the Bullet in your house. I am in the Northeast parts of US and I don’t roast in my garage but in my kitchen under a hood vent that vents out. Even inside my house (usually kept around 67F in the winter) the roasts is a little bit longer than in the summer. I also store my Bullet inside to avoid temp fluctuations.

If you’re roasting in your garage very important to have a vent system that vents out (with make up air), you probably know this from your Gene Cafe experience. The Bullet will produce a lot of VOC both during roasting and when you dump the beans into the cooling tray and that tray fan runs. In one of the hack threads I’ve some someone just run a passive dryer hose to catch the smoke and “pipe” it out underneath a cracked open garage bay door.

Good luck

  1. However long you want it to take. You could reach 2nd crack in 6-7 minutes, but it won’t be a good dark roast. 12-13 minutes should be fine. The bullet can do it and you’ll be happy with the results, once you’ve gotten a hang of it.

  2. You will clean more often and it will take more time.

  3. Just because you don’t know what Gene is doing doesn’t mean it’s better than a bullet in the cold. So, roasting on a Gene and the Bullet is a no-go outside at any temperature if you want good coffee. But if you like Vienna roasts, it really doesn’t matter all that much, since all of the coffee aroma will be replaced by roasting aroma. What I’m saying is, the Bullet might even do a better job outside than the Gene, but do you really want to play with expensive equipment out in the cold? Another question is, will your laptop withstand the cold? You do plan on using the software, I hope. Yes, even the experienced roasters use it. If you’re going at it blind, better keep the Gene.