What are people using for vent filters. A lot of the setups here seem to be filterless. I just leaned out my s4 after 5kg and it was caked.
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Currently not using one as I roast under a range vent hood that uses the baffle type “filter” which mostly catches grease. I’m contemplating whether to rig something I can hang off the baffle to filter out the fine “chaff” to save my vent motor from potentially clogging up given that the exhaust outlet (and the bean chute) from the Bullet it is pretty obvious that there is fine “chaff” being exhausted out from the squirrel cage.
Anyone else out there roasting under a range vent hood with the baffle type “filter” tried to rig something up that doesn’t compromise too much the range vent hood performance?
I installed a range hood in my garage for my HotTop and it wolrked well enough with the standard grease trap filters but it can’t keep up with the Bullet.
I have ordered some Merv 8 furnace filters from Amazon that will cover the Grease filters and am planning on holding them in place with some angle aluminum and some Brush seal weather stripping so that I can just slide the furnace filters in and out as needed.
if your range hood is made of steel or magnetic stainless steel, you might be able to creatively use some magnets on the filter to hold them in place when you are roasting coffee and then remove them when you are not roasting coffee and want your kitchen to look normal.
I posted some photos of the range hood getting clogged without extra filtering in the “Combination venting and cooling setup” thread.
The new filters will arrive on Tuesday. I’ll take some photos and post them here.
I use an air filter on my exhaust to catch some of the particles before it hits the S4. Haven’t looked at the S4 since I installed it and it’s working fine. I roasted s lot more than 5KG.
FWIW, I cut a new piece of filter every 8-10 roasts as it gets clogged.
Here’s a post where I shared the filter : Feedback on New Ventilation Set Up - #9 by lgd
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Mine keeps up well enough since it’s rated at 900 CFM.
I was thinking the similar, to get a pleated furnace filter or a sheet of the similar type of filter as the one in the cooling tray and “hang” it off the baffles using wires or paper clips 
Unfortunately my vent hood is not magnetic stainless steel.
And actually post pictures I took scissors and cut off the cardboard X to improve airflow. I do find I have to turn the fan up about halfway to get good smoke extraction. The filters definitely impede the airflow but if it keeps the fan motor clean it’s ok.
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Here are a couple of photos of the pleated air filter that I was able to install on my Range hood in the garage. I was able to slide a couple of magnets under the cardboard. (I pulled them part way out for the photo)
The discoloration on the filter was from one roast: 450g, 410 drop, 2.49 minutes after start of first crack. I could not detect any impedance of the air flow. There is a lot of surface area.
Some of my other hacks are visible in the second photo:
Stirrer
Clip on bean deflector
Extended door handle and magnetic catch to hold the door open.
Blue tooth microphone so I can hear the beans cracking.
Red paint line painted on the funnel and the bullet to verify alignment when charging beans.
Letters on the buttons painted red.
Half of the handle of the tryer painted blue, so the orientation of the tryer is obvious.
The Bullet is mounted on a lazy Susan so that I can rotate the bullet to easily access the chaff collector for cleaning.
It is still a work in progress. I currently have a mocked up cardboard shroud and need to add a dedicated receptacle for the power so the wiring is cleaner.
It never ends…
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Yeah, I’ve been thinking a lot about this filter issue lately.
I did my second three indoor roasts under my vent hood last weekend. I had a sheet of 3M “hammock filter” that I cut a piece out of. The hood vent suction is good enough that I just place it, and the suction will keep it in place. The Bullet exhaust was just below this, and the vent hood seems to catch all the smoke just fine.
I did 450g x 3 to about a City+ level, and you could see the brown oil stain on the filter, and even on the vent hood filter/baffle afterwards. It makes me a little nervous that this will eventually gum up the hood’s fan motor over the long term.
I’ve ordered some of the 3D printed 4" al tubing adapters for exhaust and cooler fans on Etsy. I think I’m going to rig up a portable flexible vent to go out my kitchen window. It’ll be cheaper to sacrifice my cheap 4" inline fan (which I will try to protect with those 3M filters) than potentially have to repair my vent hood fan down the road.
That looks interesting to use for my purpose to try out - I’m going to see if I can get some from either Lowes or Home Depot tomorrow. I too have sometimes noticed brown stains on my baffle filter but not every time I roast, interestingly enough esp since I roast to just second crack.
If you don’t mind, who on Etsy did you go with to 3D print the exhaust and cooler fan adapters? I definitely can use the cooler fan adapter. Thanks in advance.
My kitchen range hood (which I use for food, not bullet) takes these metal+charcoal filters. Wont catch on fire, and maybe better at dealing with oils than a paper filter?
The pleated filter that I chose is rated for MERV 8. Amazon has higher rated MERV filters in the same size.
I wasn’t aware of the MERV rating system.
From the epa.gov website:
What is a MERV rating?
Minimum Efficiency Reporting Values, or MERVs, report a filter’s ability to capture larger particles between 0.3 and 10 microns (µm).
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This value is helpful in comparing the performance of different filters
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The rating is derived from a test method developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE).
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The higher the MERV rating the better the filter is at trapping specific types of particles.
| MERV Rating | Average Particle Size Efficiency in Microns |
|---|---|
| 1-4 | 3.0 - 10.0 less than 20% |
| 6 | 3.0 - 10.0 49.9% |
| 8 | 3.0 - 10.0 84.9% |
| 10 | 1.0 - 3.0 50% - 64.9%, 3.0 - 10.0 85% or greater |
| 12 | 1.0 - 3.0 80% - 89.9%, 3.0 - 10.0 90% or greater |
| 14 | 0.3 - 1.0 75% - 84%, 1.0 - 3.0 90% or greater |
| 16 | 0.3 - 1.0 75% or greater |
HEPA is a type of pleated mechanical air filter. It is an acronym for “high efficiency particulate air [filter]” (as officially defined by the U.S. Dept. of Energy). This type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm). The diameter specification of 0.3 microns responds to the worst case; the most penetrating particle size (MPPS). Particles that are larger or smaller are trapped with even higher efficiency. Using the worst case particle size results in the worst case efficiency rating (i.e. 99.97% or better for all particle sizes).
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I bought them both from this guy. Just received them in the mail today. Haven’t installed either yet, but looks to be a good solution:
I had some quotes locally, and, for a single piece, were higher than both the pieces together, shipped to Canada from this seller. The exhaust adapter is a little tight on some semi-rigid aluminum duct, but I’ll pick up a flexible one, and it should work just fine.
I didn’t notice brown staining on the hood vent filters on my first three roasts, but those were pretty light, just to city.
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Thank you! I just looked at his listing… he’s Bullet owner too, he says 
I’m looking for the cooling tray adapter and he has it too. Awesome!
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Hi Bill what is the blue tooth microphone you have there.
from Amazon:
With it, I can easily hear first crack. Second crack, not so much. (But I have hearing loss and seldom venture into the second crack)
I also use a piece of 1/2 ID by 3/4 OD silicone tubing to adapt to the trier hole.
I had to taper the end of the tube with an exacto knife.
It has recharable batteries via USB
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Thanks, Bill. I think I’ll give that a try especially for the softer beans, I have some Brazil that I have never been able to hear first crack just go on temp and smell.