Comparing vacuum filters

Hey all,
Does anyone have experience with some of the commercially available vacuum filters or ideas for diy?

I’m in need of a better filtration setup for cold ethanol extraction. I’m currently using a 2L fritted glass buchner funnel with 5L flask. Using a celite bed it works pretty good, but it is a pain to keep having to empty the flask and could use something larger to save time. I am filtering 5-10gal at a time.

I’ve seen the large table top buchner from bel-art, but read that they have problems with leaking. I know usa labs has a stainless steel 6in and 12in filter that looks promising, but have not heard if they work well. They just posted a new setup in IG with a modified keg as collection base.

BVV has a stainless refinement filters as well and 20l collection base which would be really nice to be able to hook up to feed the rotovap.

Summit has the hochstrom filter, that seems like a good design. Also a really nice collection bottle with vaccum ports, but seems really expensive for what it is.



youve got the Lanphan “nutshe” filters that are really just big buchners. the problem i see with them is that there is no way to clamp/fasten a filter paper around the edges to prevent channeling. if you use a giant sheet of paper and stuff it in like a coffee maker then the vacuum does not create a seal and i would imagine flow through the paper is diminished. @nboler makes a nice setup too. i will soon be going to a 12" minimum desktop type buchner or if I can get @Terry_Manager to get his shop to make a “filter ring weight” for their big filters ill go that route. The 10l and 20l buchner is 350mm diameter. No one makes a filter this diameter but im in the same boat as you. My 2L glass fritted buchners is a pita

1 Like

so stick your current filter in a beer keg, and suck on that instead. your new complaint will be that you hate having to fill the funnel so often.

SEAL the buchner, and you can now suck in from another keg.

how do I seal a buchner? filter plate in a spool (eg see what @Soxhlet built for this trick Indofabs C.R.C & BHO Color Remediation Tek)
6"? 12"? your call

Bits. And Büchner being frozen to -40 pre-filtration.

Edit: who can identify what I used as the funnel?

7 Likes search filter. They have two options. The large refinement filter is much nicer than the regular cheaper one. I have the cheaper one it works but the Summit Research Holchstrom is waaayyy better also more expensive though.

1 Like

Ah he said emptying the flask is the problem. I read that wrong.

My problem is how slow the glass fritted filter operates, especially with a few inches thick of bentonite and carbon lol

Awesome. I’ve been wondering what kind of vac a keg can handle. How deep of a vac are you pulling using the keg?

Is it the mixing bowl off a hobart doigh mixer, or a stock pot chr and welded. Looks cool eirher way


$40 used Hobart bowl. @Concentrated_humbold for the win.

great big funnel 6" tri-clamp. so useful I made a smaller one in 4"

the handles were a major win.

haven’t managed to collapse a keg yet. tried pretty hard. didn’t throw any real pumps at the problem…didn’t really want to solve it :wink:

Edit: I actually found these funnels SO useful when playing this game with kegs that I duplicated both the 4" and 6" versions for another lab. eg, with a funnel CLAMPED to a keg, you can simply pour (or even decant) from another keg.


Lol, definitely one of those questions no one really wants to know the answer to! Thanks for the input. Im excited to start using kegs know that I have some proof of function as a vacuum filter receiving vessel. All the other options are pretty pricy. Ive seen kegs for less than $100 used plus I have a guy that will do the welding for some smoke. Thats a win win for sure :smile:


Thanks for the replies. Much appreciated

@square_root_pharms I was looking at those as well, but thought the same issue with the filter paper, I have seen similar ones on alibaba that had a large fritted funnel instead of stainless. Then you could put down silica or celite to keep the frit clean. However, i have broken a fair share of glass funnels and barbs, so I think stainless might be the way to go.

@cyclopath Good idea to put the current filter in a beer keg. I’m not very familiar with all the stainless parts though so do not know what modifications would be needed. It’s got me thinking of using a glass carboy with stopper, but implosion could be a concern.
I would like to get a filter with larger surface area at some point. It would be nice to dump in more at a time.
Not sure what you mean by seal the buchner. It looks like you made your own with a spool, filter plate, and tri-clamps. Did you weld the mixer bowl to allow more volume to be loaded at a time?

@Jay-TL Thanks, there not a whole lot of reviews on them online. The larger one does look pretty nice, I like the ring weight to hold the paper down.

They do work. I have the smaller one and use it with positive pressure 90% of the time. It is over priced for sure. Id recommend building your own. Get a custom 5 micron sintered stainless steel filter plate welded into a reducer bowl (or grab an insert style one from bestvaluevacs) then you just need to buy the spool and a top cap. No filter papers needed. Use a filter plate on top with a lid on top of that (this will help distribute the solvent and help prevent channeling. Add you valves, PRV, gauge and other components and you have yourself a dope filter for a decent price. By using a stainless steel sintered filter plate you can easily swap vac for positive pressure and boom you are ready to go. By using positive pressure you can use any old container to capture your filtered tincture.

That sounds really nice. I like the idea of a filter plate on top for distribution and not worrying about paper leaking. I still have a lot to learn with all the parts and designs, but think I get what your saying. How does the positive pressure work, do you use a air compressor or nitrogen to push gas through? How does the unfiltered liquid get fed into the funnel?

I had a funnel made, instead of round I went with square, the body and filter plate are made of 3/16 stainless, the ID is 12”x12” the height is 24” I went with 4mm holes for the filter plate, the holes stop 1/2” from the perimeter.

The filter plate is welded in 2” from the bottom. The base plate has a 4” sanitary fitting (for cleaning) welded to it with a 1/2” threaded bung in the end cap.

The housing has a capacity of 13 gallons, however I can only process about 20-30L before the filter paper slows dramatically.

I ordered 600mmx600mm grade 2 filter paper and I have to cut it down.

Total cost to machine the filter plate and have the housing welded was $550

A local sheet metal shop and machine shop did all the work based off drawings I gave them.


Here’s a rough sketch I just made of how I think that would work. The first small cylinder is the nitrogen tank, then the line to the first keg with a feed tube to the bottom and pressure coming in the side, that goes to a pipe into the sealed filter funnel, which drains into the collection keg. The little tit between the funnel and collection keg would be a barbed hose connection to relieve pressure OR be used as a vacuum port.


I’ve been planning on building a pressure filtration system myself and I hadn’t even thought of a feeder keg. I wonder if you could just use a standard valve the keg comes with along with a standard beer tap? There’s already the feed tube you would need…

1 Like

I use nitrogen but you can use air. With air you will need a desiccant dryer to make sure you aren’t adding water to the mix. I have a keg with a 2" Tri Clamp Ferrule and 3/8in MJIC connection welded on the top of a keg. I use a 2" tri clamp Dip Tube with a 3/8 in MJIC for the tincture out that connects to the 2" ferrule and my nitrogen connects to the other 3/8" MJIC connector. You can get kegs for pretty cheap and pay a welder to do the custom fabrication. Fill the keg with your mixture attach your fittings apply positive pressure and you are good to go.

Pics or it did not happen…


Let’s get some pics of y’all’s setups!

My old setup. My current setup is being built but is very similar just swap out the corny keg for a 15gal keg, the 6”x38” material column for 2 jacketed 6”x48”, the 6”x12” column for a jacketed 8”x12” column, and add a 30gal SS open top drum between the material column and filter and another 30g SS drum to catch and hold the filtered tincture. I’m also going with a pump to suck from keg and push through columns instead of positive pressure. I typically use a filter stack on the top for better fluid distribution but did not during this run. Oh and the new rig is on a nice custom SS rack.


I’m in Oregon for a week, I’ll post some pictures when I get back.