Green Coffee Buying Club
Coffee Discussion boards => Hardware & Equipment => Topic started by: EricBNC on April 05, 2012, 11:57:57 AM
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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. :)
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They are giving away 100 disk for testing through Prima Coffee. Did any here get picked to test one?
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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?
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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!
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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.
(http://i42.tinypic.com/1ovmlk.jpg)
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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'.
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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 (http://www.coffeegeek.com/forums/coffee/machines/268593?LastView=1333868344&Page=74) 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.
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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.
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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.
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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?
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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 (http://www.coffeegeek.com/forums/coffee/machines/268745#268745) 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. (http://www.coffeegeek.com/forums/coffee/machines/268415#268415)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 (http://www.coffeegeek.com/forums/coffee/machines/268730#268730), 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. ;-)
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I have a buddy with a 3d printer. If I had a file I might be able to do something.
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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:
(http://i43.tinypic.com/35m2ozq.jpg)
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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.
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Thanks for the compliment :D
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.
(http://i41.tinypic.com/156tpu8.jpg)
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I don't get the problem with the Aeropress basket. So, 2/3 of the screen is blocked. The screen is big. We don't need all the coffee to flow out at once. Slow is part of the design.
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My experience leads me to disagree. Among Alan Adler's scores (hundreds?) of posts in the Aeropress thread at Coffeegeek, where a huge number of issues with its design were hashed out as perhaps with no other manual device on the planet, not once did he indicate that "slow is part of the design."
(And I'm STILL getting the links wrong-- ARGH -- the posts just BELOW the posts I linked to, people. Good grief. I can yammer coffee at CG till the cows come home, but I can't get the links right. Seriously, read that background material. It'll help.)
To the contrary, "slow is part of the design" has been largely repudiated as a principle in the growing popularity of the "bottomless" dripper cones that recognize that rate of flow is properly under control of the person doing the brewing. It is not properly a constraint on that person's prerogative to vary the brewing variables at will. The engineer's proper goal is to get out of the way of the brew -- by which I mean constrain no variables.
Now in truth it's different in the consumer world. Joe Consumer needs to be told how to do stuff, often enough. But I think we're talking in geek territory, where literacy with and fluency in the brewing variables is our bread and butter. We don't want our degrees of freedom, our axes of operation, limited by some designer who has "how do I do this?" Folgers or Flavored folk in mind.
But Alan Adler was no such designer. This was one of the few failures in the design of the Aeropress. As with most design failures, it didn't result from the failure of a zealous quest to find the perfect cap hole design. It resulted from deeming that a relatively unimportant issue, with no quest at all. Bear in mind that Alan was not, and is still not, a coffee geek per se. He's merely a design geek -- and a good one. But on this he dropped the ball. And why not? For precedent he had generations of coffee device designers who labored under the delusion not that flow rate was unimportant in devices like dripper cones, but that it was valuable to limit the flow rate to "help" consumers get things right.
It makes sense. If Joe Blow uses a grind that's too coarse, it helps to slow the flow so that wet time is increased. It self-corrects. As the grind gets finer, the holes in the dripper become less the choke point than the grind itself.
But that's for a less literate age. It's seriously time for designers to turn the corner and not coddle Jane Consumer. If she's willing to buy a manual dripper in these far more coffee-literate times, by golly, take that as a sign that she's probably willing to learn the basics about brewing variables. Why not? She's taking her coffee seriously, finally, the same way she takes her Slow Food or Local Food seriously.
(this is turning into a manifesto asserting a particular value on the cultural issues bearing on the question of coffee device flow rate, a true sign that GCBC is every bit as geek as CG)
None of that's relevant to the Aero anyway, it's just pointing out that ways of thinking about flow have been . . . unfortunate in the design world in general. Alan had few examples -- if any! -- of devices that took this concern seriously.
Well, to conclude instead of meander further -- no, we DO need the filter to be wide open. That allows the person doing the brewing to architect his own extraction with no needless limit on the range of the flow variable. Being satisfied with a limited flow rate because it may happen to match your own balance of the variables -- that is, thinking the design is fine because you, personally, don't need it to be different, is not good thinking -- or at least, not generous thinking. It indicates kind of a "why would anyone concern themselves to do things differently than I do?" attitude. I'm not accusing you of actively not caring; I'd just suggest that personal contentment with a thing doesn't instantly motivate one to advocate for changes to that thing to serve purposes valuable to other people (where those changes would not affect your own use). I personally shrug about most sports -- but I wouldn't advocate bad seating designs at the stadium. ;)
This may have been what happened with Alan in the cap design. But designers should never shrug off something like that -- especially with an insane number like 68% obstruction.
Some of this is just illusion in action. "Ah that filter has a lot of holes in it. No biggie." OK, so if I gave you a filter with 2/3 of them removed and also gave you a device that allowed them all to effectively pass fluid, would you not ask me "why didn't you put more holes in this thing? there's a lot of flat metal between relatively few holes here!" Of course you would -- rightly. This proper judgment does not become moot merely because the holes are rendered ineffective by their use in a particular device. In the case of the original Coava and Able filters, they already have too few holes. That was known the moment they hit the street by anyone familiar with previous generations of similar devices, and the constancy of this critique doubtless led to the version we now anticipate getting our paws on.
Gah! I yammer. Up and out.
Credo: "Free the Flow!" ;D
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If you buy or make a metal filter, you could take a hot knife and cut a huge section out of the middle of the stock black plastic bottom. With paper, the grounds and filter would spill through thanks to the paper filter's lack of rigidity. The Able is rigid and would hold shape and still perform as a filter even with out the bracing provided by the honeycomb of plastic lattice work.
Something that looks like my crude rendering would be easy to make - then the theory would be put into practice:
(http://i43.tinypic.com/52xrti.jpg)
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I still don't get it. Even with the Coava screen, you will have, what, 50% obstruction. It sounds to me that you want a electro-magnetic super laser beam at the end of an open pipe. I am not trying to be snotty. It just seems necessary that there will be some obstruction, and it is up to you to press the water through the filter at the right time.
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Yasbean, my thoughts align closely with yours, but testing Rasqual's theory would be easy if someone does not mind cutting on their Aeropress part.
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I still don't get it. Even with the Coava screen, you will have, what, 50% obstruction. It sounds to me that you want a electro-magnetic super laser beam at the end of an open pipe. I am not trying to be snotty. It just seems necessary that there will be some obstruction, and it is up to you to press the water through the filter at the right time.
Then take away 68% of the 50%. :P
"My rotator cuff motion is limited to 50% of its normal range. Why would I worry about it being reduced further to 16% of normal!"
16%! The logic of "it's already limited, so what's with still more limits" is precisely backwards.
The issue is this: why artificially limit the flow? It's a brewing variable. Would you want someone to tell you you could only brew for between 4:15 and 5:15 minutes -- never outside that range? Or would you buy a grinder that was designed to permit only certain grind levels and not other useful ones? What if manufacturers didn't offer you boilers, but water heaters that took pains to make sure the temperature never got over 196 degrees?
You would think all of these artificial constraints on brewing variables to be preposterous -- and rightly so.
One of the Aeropress's virtues is that termination of extraction can occur at any time. Having a faster potential flow rate (the actual flow rate is determined by you, the user, when you press) permits even more control -- a briefer window of terminating that extraction. This depends on grind, of course. Compounding the matter is that much of an Aeropress's extraction occurs during the press (my own theory: well more 50% with a relatively fine grind). This commends (but does not require) a grind that's coarser than the threshold for grind-as-bottleneck, which means a quick termination in many cases may (but not must) depend on a maximal flow rate.
Basically, yes, an open pipe would be ideal. Absolutely. Positively. (in fact, as a teenager I once applied that same logic to a diy bong ;-)
That's why we like the Hario and comparably open drippers. That's the entire point. Only the user's discretion should limit that brewing variable of flow rate -- not a kindly manufacturer who delusionally imagines they know how to constrain your wisdom in how you, based on other constraints you may have with technique, grinder etc., put the variables to work.
Think of it this way. Look at the limit cases. One tiny hole in the middle of the cap. "That's absurd." Agreed. Wide open pipe. "That's abs..." Hold on. No, it's not. Not in all cases. You're capable of slowing the flow by introducing your own impediments. The Coava/Able filter's own limited number of holes does so -- dramatically. Your own preference for impeded flow (which I'd actually believe is your mere indifference to less limited flow -- I don't think you're consciously preferring limits as you are just not sure why having no limits is important) is not defeated, but those wishing to exploit the greater flow are free to do so. The full possible range is there, and there's no downside for those who prefer impediments. The Coava/Able filters would impede flow more, I dare say, in a wide open pipe than their upcoming replacements would do in a conventional Aero cap. Seriously. Think about that.
Think of it this way: a good scientific theory is fruitful of further work in that area, further theories, more experiments. Likewise, a well-designed brewing device can either constrain everything and deliver perfect coffee (analogous to having discovered the scientific grand unified field theory) or, since we don't have that, it can allow for control of any and all variables within any possible range, so that the coffee experimenter can dial in whatever he wants, however he wants, without having to suffer the limits of his apparatus. "We can't explore the complete range of variables x, y, and z -- because variable w is pegged at a maximum of whatever and thus no function of these variables can exceed w's limit." If w were wide open, the range you could vary x,y,z would be wider.
I can -- and will -- argue this successfully. By which I mean I will persuade you and make a believer out of you. Just be patient with me. I might introduce graphs to make the point visually. And I will succeed. Not because I've created a right idea, but because I'm defending the purity of wide-open boundaries in the world of coffee brewing variables. The Aeropress is a hot rod that allows varying the variables more than with any other device. To defend its one bad design element in this respect -- flow rate when surface filters are being used -- is virtual heresy because the theology of the Aero, this element aside, is libertarian variables. With drippers I might grumble about people defending artificially limited hole sizes and such. With the Aeropress, it's Athanasius contra mundum. This is war. ;D
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Then again, most of us are perfectly content with the imperfections of the current design and see no need for improvements. Or as grandpa often told me, "If it ain't broke don't fix it!".
edited: A prime example of when to apply the Pareto Principle and when not to. Is it better to spend 80% of your time to get a 20% improvement in AP filtration, or would it be better to spend the 80% improving bean selection and roasting skills?
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The resistance of the cap is in series with the resistance of the ground puck. The total resistance would be the sum plus any border impedance. This isn't a bottleneck/parallel situation, where smaller component resistances get bigger flows.
The pressure during brewing is related to the total resistance of the filter and the puck. Too little resistance would mean very little pressure in the brewing container. So in effect you aren't really expanding the experimental range, you are just sliding the experimental window towards behaving like a small plastic french press.
Another issue with providing the majority of the resistance in the ground puck would be uneven extraction rates along the puck due to the pressure drop within the puck. One end would be subject to chamber pressure, the business end would only have the pressure provided by the resistance of the cap. Increasing cap resistance and increasing grind would make the pressure differential smaller across the puck.
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Okay, wait a minute! If you want to reduce the obstruction of your Aeropress by 50%, why not just increse the diameter of the disk/cap by 50%? Voila!
But, the Aeropress is the size it is, and if it takes me 5 seconds longer to press my coffee out, then I will begin 5 seconds earlier, or 3 seconds earlier and press harder. Now try pouring harder with your open drip and getting better control of time.
I like Yakster's idea of experimentation over theorizing. I respect your philosophical prespective on this, but... wait a minute, I need a cup of coffee if I'm going to keep this up.
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The rule around here seems to be, "When all is said & done, less is done than said."
Show me the modified filter holder or go away - quietly!
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...Show me the modified filter holder...
Yes, please! rasqual, given your passion about this issue (since 2006, apparently), I'm a little surprised you haven't just tried the mod. I don't mean to pile on, but we're talking about a $9 part on a sub-$30 brewer... ;)
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Tex, jbviau: AGAIN with the links. In order for you:
http://www.coffeegeek.com/forums/coffee/machines/268740#268740 (http://www.coffeegeek.com/forums/coffee/machines/268740#268740)
http://www.coffeegeek.com/forums/coffee/machines/268478#268478 (http://www.coffeegeek.com/forums/coffee/machines/268478#268478)
http://www.coffeegeek.com/forums/coffee/machines/268745#268745 (http://www.coffeegeek.com/forums/coffee/machines/268745#268745)
Okay, wait a minute! If you want to reduce the obstruction of your Aeropress by 50%, why not just increse the diameter of the disk/cap by 50%? Voila!
Why would you throw more material at something if merely increasing the porosity would have the same effect? That's like having a minivan 68% full of debris, so because you can't fit all the kids in it you trade it in for a 12 passenger van which you ALSO have 68% full of stuff. Why not just make it more efficient? -- not bigger with the same inefficiencies. :P
But, the Aeropress is the size it is, and if it takes me 5 seconds longer to press my coffee out, then I will begin 5 seconds earlier, or 3 seconds earlier and press harder. Now try pouring harder with your open drip and getting better control of time.
I'm not arguing that you cannot make do. Anyone not wishing to brew using techniques that take advantage of higher flow rates will do quite fine with it. That's not going to make your coffee any worse or better, because there are myriad ways to juggle the brewing variables and get a great cup. I'm arguing that the Aeropress's cap could have been designed to be more efficient with surface filters -- which is what it's sold with, and which the Able filter is. Against that argument I'm not sure what possible argument could be constructed. Arguing that it's OK for you is not a counter-argument against the proposition that it would be a more flexible brewing system were its cap better designed (using less material, in fact). It does no good to protest that the town wouldn't benefit from an expanded public park merely because you only play chess in the tables on the corner of it. ;)
I like Yakster's idea of experimentation over theorizing.
Argh! That's all those threads at coffeegeek were -- experimenting.
The resistance of the cap is in series with the resistance of the ground puck. The total resistance would be the sum plus any border impedance. This isn't a bottleneck/parallel situation, where smaller component resistances get bigger flows.
Yes and no. Again, a limit case. If your puck is fine grind / thick / tight pack, the effect of the cap hole size is negligible. The puck is
[edit: ? I have no idea what I lost when posting]
Another issue with providing the majority of the resistance in the ground puck would be uneven extraction rates along the puck due to the pressure drop within the puck. One end would be subject to chamber pressure, the business end would only have the pressure provided by the resistance of the cap. Increasing cap resistance and increasing grind would make the pressure differential smaller across the puck.
That paragraph excellently introduces a less frequently mentioned brewing variable -- because pressure has traditionally only seemed relevant for espresso. But that's probably because it actually is relevant only at such high pressures (analgous to time dilation's triviality at Newtonian velocities ;-) The agitative effect of flow through the puck, I'd assert, is what's most a factor in Aeropress extraction.
Key point remains: You can add a Coava and impede flow through an Aeropress, if that's what you want. There's nothing you can do with the existing cap -- short of the mod I link to above (or similar mods) -- to improve flow. Were it designed as I suggest in one of the other two links, you would still be free to impede flow with a suitable drop-in filter, but you'd be as free to take advantage of improved throughput with surface filters because you'd have three times the filtering surface working for you.
You can always add impediments to flow. But the only way to eliminate them is to open things up -- either with a depth filter, and/or with a better cap design.
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I don't hang at CG much any more, but whenever I drop in to check things out I notice that the expertise over there has improved dramatically. Not that it was ever bad -- but there're some extraordinary people hanging out there, whose base knowledge is way, way into the stratosphere in a lot of relevant disciplines.
CG continues to be a very, very cool place.
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I'll have to check out CG again - oops, forgot, they're blocking me.
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I'll have to check out CG again - oops, forgot, they're blocking me.
One site's trouble making troll is another sites loveable (but banned) curmudgeon. ;D
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I'll have to check out CG again - oops, forgot, they're blocking me.
One site's trouble making troll is another sites loveable (but banned) curmudgeon. ;D
It's only because of guys like you who goad Tex, and misunderstand Tex, and don't give Tex the respect he deserves, that he acts out around here. Some of us truly give the venerable veteran the honor he's due, and if we all did, we'd see the kinder, gentler Tex he wants to reveal.
;)
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I'll have to check out CG again - oops, forgot, they're blocking me.
There's a story in there somewhere...
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Tex, jbviau: AGAIN with the links. In order for you:
[url]http://www.coffeegeek.com/forums/coffee/machines/268740#268740[/url] ([url]http://www.coffeegeek.com/forums/coffee/machines/268740#268740[/url])
[url]http://www.coffeegeek.com/forums/coffee/machines/268478#268478[/url] ([url]http://www.coffeegeek.com/forums/coffee/machines/268478#268478[/url])
[url]http://www.coffeegeek.com/forums/coffee/machines/268745#268745[/url] ([url]http://www.coffeegeek.com/forums/coffee/machines/268745#268745[/url])
Thanks. I'd missed the pic of your modded cap when I skimmed that humongous thread before. I read a few pages downstream from each of the posts you highlighted and still came away unclear as to whether or not the poly filter experiments you described were done using the modded cap. Would you mind clarifying?
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No, poly filter experiments with the modded cap would be moot. Poly is a depth filter, which partly defeats the cap's design flaw because lateral flow is possible in such felts. The 68% obstruction issue is only relevant with paper or metal -- surface filters. Or better said, surface filters are far and above the first candidates for concern with regard to effect of the flaw on flow through such filters where they're pressed up against the cap surface.
To this day, I esteem poly as the ideal filter for the Aero. It's ideally suited to a method that finishes under pressure. But I don't think it would be practical on the market. It's too expensive to use only once (if one makes a habit of that), and it's troublesome to clean.
I also used the material for a couple years in large manual pourovers. It's stellar if you like oils in the cup (other than flow rate, its other virtue). But that's REALLY impractical to clean.
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I looked at those links too - can you tell us what improvement this exercise produces in the cup?
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The mod itself has no consequence in the cup. It just removes a variable constraint. Increased flow just means you can go with a finer grind, or press more quickly, or avoid filter stalls if your grinder generates dust, and so forth.
One consequence of the finer grind benefit is related to the "redeems a whirly" thing with the Aeropress. That's true anyway -- but it makes extraction termination a bit quicker when you have three times the surface area to press through. Perhaps part of the reason I value this is because in addition to its virtue of passing oil, the poly felt has just spoiled me with its flow rate. Getting that flow rate for paper is only possible by decreasing the proportion of that paper in pressed contact with un-holed (think Shakespeare, here, and pronounce it "un-hole-ed" ;-) plastic. The popularity of metal filters as their pore size decreases I take as a good thing -- but they're still surface filters. I'm painfully aware of this because of the huge difference between surface and depth filters ESPECIALLY when pressed against surfaces that rob them of their full surface area.
This won't make any cups you're already doing taste better, as far as I can tell. It just gives people with different constraints, wider latitude.
note: I always vacillate between schools of thought with the Aeropress regarding grind size. I rarely use poly of late (and mostly use dripper of late, anyway), but here at the office I just now went and made a poly press (inverted to get max oils) of a good Harrar. I used a whirly, ground quite fine (I usually use burr, and coarser). I preheated the Aero, and agitated the grind really well (I'm erring on the side of over-extraction lately). The press yielded the ridiculous oils (same as this picture of old (http://www.coffeegeek.com/forums/coffee/machines/268272#268272)) I've come to expect from the method, and -- good grief. Best cup I've had of that Harrar in a while.
I really do like the oils with lighter roasts, and I like cleaner cups with darker roasts. I recall cupping some "nondescript" coffees a few years back, though, and their oils made things worse regardless of roast level. How much actual flavor is in the oils, anyway? Interesting stuff...
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Hmm...
As usual, rasqual's ideas about filtration, and lateral flow filtration specifically, set me to thinking (a risky thing).
1st thought: Coffee grounds aren't stacked linearly in the filter; that is, water flows in all directions as it passes through the grounds. That means the exit holes and their arrangement is moot, as long as they're of sufficient size to permit a rapid flow when the plunger is depressed.
2nd thought: I question whether further lateral flow of coffee after it enters the filter serves any purpose, other than possibly correcting for a bad grinder that creates too many fines. It's been my experience that, regardless of brewing method used, properly ground coffee is more important than filtering devices.
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Yer showin' a good novice understanding of the issues. Keep thinkin' dangerously. ;)
And amen to the grind. I want a roller! ;D
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Macro photo with front and back light! Beg, beg! :)
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So, is this worth the pre-order?
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Dog, I should have mentioned that I have the regular version metal filter already.
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bump :)
Macro photo with front and back light! Beg, beg! :)