I have seen how the smoke build up affects glass, so I can only imagine the nice yellowing it does to lungs.
If you do one 350g or smaller batch, then nothing more than a cracked window is probably good enough.
The other thing, is that smoke residue can cause a type of nose blindness. Not sure how many of you come from a working background like me, but I have done metal work and couldn’t smell or taste anything beyond sweet and salt for 48hrs. So if you go from roasting in smoke to cupping, it can throw off your perception. Which may not matter unless you are a solo roaster.
No need to mess around and find out. I think we care about your health and career enough to share experiences. But obviously it is your choice, and you may have additional reasons, such as traveling with the bullet and only minimal roasting needs. So can’t really give you hard rules. But in general…
Ventilation is a good thing, if you can accommodate it.
Wow - I’m really surprised that that ever worked as a grill - wouldn’t think you could create a strong enough draft from convection alone.
I think the problem with your first try is that the static pressure is too high for the fan used. And, I never trust those fart fans to do much anyway - most are engineered with no economy spared. Certainly the CFM rating assumes an almost zero static pressure.
I would think that a duct fan would be designed for a higher static pressure, but I don’t have any direct experience. Squirrel cage type blowers are usually capable of moving more air in high static pressure situations, so that might be another route to go.
Let us know how your experiments go!
-Gray
PS - I like your lights - think I’ll steal the idea from you!
I am fascinated by the ingenuity shown in the various “venting” solutions created by Bullet users. We do custom engineering of systems designed to filter chaff, smoke and odor from roasters in the 5 to 500 Kg range; seeing these many solutions makes me want to come up with a “canned solution” just for Bullet.
This thread has been super helpful trying to come up with the best venting solution. From my reading, it sounds like the 6" affinity fan has been the “best” option for a few people. They sell a bundle on amazon that comes with the fan, ducting, and a carbon filter, found here for reference. Question for clarification hopefully someone can answer:
Is the carbon filter that affinity sells “necessary?” Or is the inline filter box adequate? @krame your setup looks like exactly what I would like to do, curious on your thoughts on the carbon filter vs. the inline filter box…
I’ve attached a drawing, I’m very visual, of what I view as a kind of “schematic” or whatever.
Did I miss something? Would you recommend adding another feature somewhere within the schematic?
I use the same system but with the 4" version. I’ve found the inline filter box to work well. It’s certainly more economical as the carbon filters seem likely to clog more quickly and are much more expensive from my recollection. The box filters are also cheaper and easier to find from various sources/manufacturers.
So with my specific setup and needs, I found the 6" fan and filter box to be unnecessary and a financial burden.
I have a roasting “business” and I’ve roasted on the bullet weekly with few exceptions since July of 2022. Probably average 3kg (hence the quotes around “business”) with an outlier of a 50kg order for a business gift basket.
I found that it would be cheaper to just run the fan until it breaks than continually replace the filters.
I recently moved my roaster closer to a window, so my bullet to outside distance is maybe 3ft. I downsized to a 4" viviosun fan and have not had an issue*. I’ve been running the 4" fan for a couple of months now without a filter without a problem. But I also have a replacement fan ready to drop in.
YMMV.
*When I drop the beans I get a puff of smoke as the cooling tray fan briefly redirects the smoke back out of the vent intake. This did not happen with the 6" fan.
Awesome, interesting. Ill be about the same distance from a window ~3 ft. Good to know about the cost of the filters in the long run, that also seems like an issue of scale “down the road” as you do more roasts etc. I saw one post where someone place some kind of “filter” over the exhaust tube ingress, which looked a “good” economical solution. Thank you!
Did you try other fan types before settling on the 4" viviosun, other than it’s big brother? I am currently using a chinese cyclone fan (metal fabrication rather than plastics) and it has stood the test of time with and without filters). Canberra climate so not as hot as some but def colder than others
Since I’ve picked up a ton of advice from this thread I thought I’d pitch in with my slight additions.
I’m roasting indoors, I have two 4in. ducts picking up roaster exhaust - one is connected to a 4-6in. step-down that acts as a hood and the other is connected to a 3d printed adapter and then into the Aillio cooling tray. Those two ducts go into a 4in. Y that has a short run to another 4-6in. step down to an AC Infinity Filter box then a 6in AC Infinity fan and then another short run to a 4-6in. step down and out a wall mounted dryer vent. The roasting room is completely smoke free and I am cooling 600g of roasted beans in 2 minutes.
The biggest change I’ve come up with is a metal filter screen instead of the poly filter material. I have two layers of galvanized rodent screening material tack/ soldered together perpendicularly to create a fine enough, but stiff, mesh that holds all the chaff. This slots in front of some 1/4” mesh that I’ve bent around the fan.
I could probably do without this extra layer but I wanted to be able to vacuum out the chaff between roasts and there’s so much suction going both ways that I thought it better to have the thing the chaff was against be movable but not able to get angled into the fan, and cause all the chaff to get brought into the duct.
It’s not nearly as complex and it might sound and works great.
I vent the chaff Down and Out exhaust up and out use the number 2 setting on the inline exhaust duct fan then turn it up to 4 after first crack. The chaff is collected in a screen bucket outside.
Here is my setup and venting solution in the garage. When I roast, I simply open the garage just enough to let the hose go through and up onto a platform right outside the garage so the smoke can be dispelled into the air. The AC Infinity filter box with a MERV filter does a good job in filtering the smoke.
The 6” hose and 8” register are screwed into a spare 2 x 4 I had lying around so that they are fully suspended above the exhaust and there is an air gap. There is a Y-splitter with 6” and 4” connection; the 4” goes to the cooling fan with an air gap. In the future, I’d like to order the adapter for a direct connection, but it seems to work well now.
