Able Company Disc Fine Aeropress Filter

[EricBNC]

From Prima Coffee's post on Home-Barista:

"Able Company has made a new Disk for the Aeropress that has smaller holes and is thinner than the old Disk. As they determine whether they will go into full production mode, they asked us to help them ..."

So a new permanent Aeropress filter disc with smaller holes is a possibility if all goes well in product testing. 

[RobertL]

They are giving away 100 disk for testing through Prima Coffee. Did any here get picked to test one?

[Tex]

Other than limiting the amount of fines that get passed, what would be the advantage of a finer filter? It seems to me that the grind determines the results more than the filter?

[Tex]

I once had a Black & Decker vac pot that produced a coffee as clear and free of solids as any I've ever seen. If someone could make a reusable AP filter out of whatever B&D used they'd be on to something!

[EricBNC]

Great question, don't know the answer.  I think Able is playing with this too as they haven't made formal plans to release this as a product until they get feedback from a trial.  I also think it's smart marketing since this was a product originally released by Coava Coffee and since spun out to Able Brewing Company, and this giveaway gets their name out there.

Some things I can think of off the top of my head.

• Cleaner cup with less solids for people who want a re-usable filter and coffee oils with easy clean-up but get a results more like a paper or cloth filter
• Slower drain making it potentially possible to use the Aeropress normally instead of inverted
• More tolerant of cheaper grinders that produce fines and boulders, not having to worry about sieving your coffee to prevent silt
• More money for Able Brewing by releasing a new toy that everyone will want to buy
• Getting to say that your the first on your block (blog) to have the latest toy

I can use the Aeropress normally (not inverted) with the home made disc I cut from a scrap juicer screen.  It has smaller holes than the 0.10 disc  - I am getting the Able Disc Fine too - I got interested in this since the material used looks finer than my effort.

[jbviau]

I am getting the Able Disc Fine too...

I've got one coming as well. Looking forward to trying it out! I'm all about metal filtration, but I'm a DISK newbie, so this should make for some fun experimentin'.

[rasqual]

Here's the thing about the current design.

The metal filters, like paper, are a "surface" filter. In the case of the Aeropress, only about a third of the filter is useful. The remainder is pressed tight against the plastic, and you're not going to get much flow through it. So when you look at the current metal filters, the number of holes actually doing any work is quite small.

See here for some context. Follow the link at the end of that post, too. From that link, scroll up as well.

Metal filters could easily be redeemed by "denting" the downstream side in a convex way between the holes. This would prevent two thirds of the holes from uselessly being pressed against the plastic where they can't pass any fluid at all under pressure.

Seriously, does no one understand this basic fact about the Aeropress cap?

edit: Something I haven't tried but it should work: Use a pinvise and bore tiny holes in the cap where shown. Press conventional  sewing pins through from the inside. Carefully Dremel the excess off the outside. You now have some nibs in the cap that might help more of the holes to pass fluid. Useless with paper but might help with the current Able filter. If they make it thinner so that it's more flexible, perhaps not so much.

[EricBNC]

Not sure the small area used after taking the bottom cover blockage into account is a terrible problem - the paper filter presses against the same bottom too.  A more elegant solution would be to make a "naked filter" - a mesh filter that screws into the bottom of the Aeropress which replaces the original bottom filter holder.

[jbviau]

rasqual, the new DISK Fine *is* very thin and bendy (see below). I'll also attach a shot of the DISK Fine in the cap and held up to a light source. Enough holes for you? I count 19 per opening.

[Tex]

Here's the thing about the current design.

The metal filters, like paper, are a "surface" filter. In the case of the Aeropress, only about a third of the filter is useful.

snipped

Good point about the "actual" filtering area. If one never intended to use paper filters again, I'd bet every other hole in alternating rows could be redrilled to twice its current size to allow more filtering surface?

[rasqual]

Not sure the small area used after taking the bottom cover blockage into account is a terrible problem - the paper filter presses against the same bottom too.  A more elegant solution would be to make a "naked filter" - a mesh filter that screws into the bottom of the Aeropress which replaces the original bottom filter holder.

It's not a small area, though. It's actually two thirds. That's a geometric fact. I proposed a re-designed Aero cap that would increase the hole size to, basically, 100%. As if anyone wants to tool up to mod a product that no one raises this complaint about.   

Yes, the paper does too. It's the same issue with ANY surface filter on the Aero. The experimental results bear this out.

Tex, follow the links.    Whoops, the first link wasn't quite right. Here. See the above link as well. You don't need to go all the way through. A poor man's fix just enlarges each existing hole on the inside, leaving material on the outside to maintain cap strength. You only need to expand the open surface on the inside where the filter meets it -- not all the way through.

I definitely want one of the new filters -- but it doesn't change the fundamental problem at all. Oh the performance will likely improve -- I can't imagine how it wouldn't. But imagine how it would improve if you TRIPLED the flow rate. That's actually possible with an ideal -- and doable -- cap design. Think about that for a second. If your car's gas mileage could be trebled with a simple design change (better yet, foresight), you'd think the manufacturer mad if they didn't do it. Yet the Aeropress's cap actually suffers this problem.

Skeptics must do the diligence. Start by pressing through paper alone. Then press through paper and poly felt, with the felt against the cap. Note the difference. This isn't a solution, just a means of testing the hypothesis that the surface of the cap, mated with surface filters directly, impedes flow. With the poly in play against the cap, flow rate will improve.

Counterintuitive until you ponder how the felt's depth permits sideways flow, allowing fluid to flow through felt located over the solid plastic parts of the cap and migrate to where there's a hole.

Actually, I guess it kind of is a solution, but it's an impractical one. It'd be inapropos to call it a "stop-gap" approach, though, since it kind of does the opposite.    ;-)

[ScareYourPassenger]

I have a buddy with a 3d printer. If I had a file I might be able to do something.

[EricBNC]

Rasqual, the grounds form a layer of silt across the bottom of the filter - this impedes the flow almost 100% till you add some back pressure - I am still not convinced there is a problem. 

Below is a shot of Josh's Disc Fine and my disc made from a juicer screen:

[rasqual]

Sure, but that pressure ends up passing the fluid through cap holes that occupy 32% of its surface. The filter's remaining 68% surface area presses against the solid portions of the cap under the very pressure that forces fluid through the other 32%. No fluid can pass though that 2/3 of the cap. In a backpressure environment, this matters.

The fact that the grind resists flow is an entirely independent matter. Well, not quite. It's certainly possible for a grind that's remarkably fine to make my concern moot by passing fluid more slowly than the 32% surface -- that is, the bottleneck could be the grind itself.

But that's kind of like the issue where dripper manufacturers used to all boast that their ill-fluted designs had optimally sized holes in the bottom for a perfect flow rate. Since they all had different sized holes, basically they were all out to lunch. Marketing hooey. If you used a fine grind, your grind determined the flow rate (because the holes could have kept up with more). If you used a coarse grind, the holes would be the thing to slow your flow. Thankfully in the last few years we've seen manufacturers realize that proper design leaves the flow rate as a function of grind selection -- not backpressure beyond the user's control. Likewise with the Aero -- an ideal design maximizes flow and leaves actual flow rate to the user's use of grind, pressure, and time.

Your juicer screen disk looks sweet.

[EricBNC]

Thanks for the compliment 

I call it a screen from a juicer but I am not certain that's where the part comes from. I find these cylinders from time to time in a local thrift store and i think they come from cheap juicers people use a couple times and then toss out.  They sell for less than a buck - usually a quarter will take one home.  The bottom half shows the inside of the part - it's not too hard to cut or melt away the plastic from the metal. Once free I can cut a few of these out of one strip of mesh.