These are 5, 25, and 50 micron polyester felt filtering sheets (12" x 12"), respectively. Slightly pressed, they're about as thick as a penny. They're relatively inexpensive.
I cut a circle from each to fit the Aeropress.
The 50u filter produced fines. So did the 25u. The 5u did not. Note: in the case of these three brews, I was using a whirly.
I did another batch later with a 5u circle, using 15g fresh roasted coffee ground at Drip (exactly) in a Solis Maestro Plus and 8 oz. water a minute off boil.
I knew from the previous batches that I'd have to start the brew in another container to avoid wash-through, but figures I'd skip that just to see what happened.
I put the coffee into the Aero, added the water, and stirred. I weighed the wash-through just before pressing; I had 3.6 oz. wash-through. I then pressed, and ended up with 7.4 oz total extraction (so a grind holds about twice its original weight in water?).
I ran the coffee through a conventional Aeropress filter and there were no fines -- none.
At the moment I can't comment on the presence of oils in the cup, or not.
Note: A Clover filters at best around 40u, at worst around 100u. Based on what I'm seeing here, fines disappear somewhere beneath 25 microns, so present Clover screens aren't likely to be rid of fines. A metal screen compliments of Alan Adler was 127u.
The picture below shows the polyester filter unused (left), used and rinsed (center), and on the right is the paper filter after running the resulting brew through it to screen for fines (which weren't present).
I have yet to do a 25 using the Solis, which is likely to result in a lot less fines than the whirly. I think.
Yirga Senior Member Joined: 3 Feb 2006 Posts: 659 Location: Big Bend Expertise: Just starting
Posted Tue May 16, 2006, 7:48pm Subject: Re: Polyester felt filtering material in Aeropress
I am very aeropressed with your venturing back to a '60's manner of dress which has been long overlooked for it's contribution to civilization. I still have some old polyester jackets and pants I need to get out and recycle into today's world. I could also listen to, "Yellow Submarine" in doing so!
If polyester will pass coffee oil as well as the, "Blue Meanies" did their job, we'd really be getting somewhere!
Keep up the good work, Rasq! But stop short of making a filter out of, "Ole Stink Foot's" silk socks!
What about Gore Tex? Did Al Gore invent both it and the internet?
Posted Wed May 17, 2006, 1:52pm Subject: Aeropress and coffee oils
Whokay, the 5 micron polyester nails it. Holy cow.
Using the inverted method with the Aeropress -- which means doing the somewhat lame press-upside-down-until-you-almost-make-a-heckuva-mess thing -- I got a ton of oils in the cup. No problem.
I was wondering if the polyester would pass oils. The answer is an absolute "yes."
I'll post some pics later.
Suffice it to say you can get all the oils you want, and no fines, with the 5u poly. Not sure how long you can run around recycling one before it gets yuck, though. I'll be using a mild, neutral surfactant on one to see how long it lasts before it's absurd.
Posted Wed May 17, 2006, 7:35pm Subject: Re: Aeropress and coffee oils
Blast it all!
I need better glassware. I think I can get what I need on the morrow.
I brewed two doubles (30g grind ea., actually) and let the extraction settle in a narrow glass vessel. Unfortunately, my photos of the surface are garbage. What I WANT to do is have the top of the vessel so narrow that the oils are actually deep enough to measure!
But I can say this from what I saw with my own eyes -- well, let me back up. I mixed the brew in a separate cup, then poured it into the Aero -- one brew normal orientation, the other inverted. I controlled all variables pretty closely. I felt I had to do it this way 'cause the wash-through with a normal orientation mixed in the Aero would have made that instance a very different extraction -- less water over the minute period with a drip grind I used.
Anyway, the inverted method with the 5 micron polyester felt CLEARLY AND OBVIOUSLY passed an unbelievable quantity of oils into the cup. The normal orientation DID NOT. I'm shouting because I was surprised at how obvious and substantial the difference was.
Bear in mind, the inverted method consists in actually pressing until most of the bloom has dissippated through the filter. This results in the holes of the cap filling, and the extraction beginning to well up atop the inverted cap, threatening to drain off the top of the cap and make a mess. A timely, deft turn upright avoids a spill, but this is as inelegant a method as one could imagine.
I'm going to see if I can find the glassware I need to do this right so I can provide some photographic demonstration. I'll also do a paper filter, and might even do Alan's metal -- though I don't like that 127 micron size (that's at least 5 times coarser than where the fines begin to disappear).
Oils. Inverted. Five micron polyester, people. Believe it.
That was my thought, too. But maybe you still have to keep the high voltage generator going until the big lightning bolt hits!
Oils floating to the, "bottom" doesn't seem to be much help if the polyester passes coffee oils, anyway, right?
Watch out for a huge glow in the night sky in the direction of Aurora (has it ever NOT been that way?) Polyester is never anything to play around with! Lucy in the sky with diamonds!
He says it tastes like espresso! I want it to taste like espresso! But Alan said it already tasted like espresso! You mean, we got, SUPER ESPRESSO? Can that be possible? Hey, Mark -- Yah, yah, yah, yah, YAH, YAH! Don't we have to notify Homeland Security? Ground Control to Major Tom!
virginiacoffee Senior Member Joined: 22 Mar 2004 Posts: 49 Location: Southside VA Expertise: I live coffee
Espresso: Magister Home, Krups Gusto Grinder: Zass 169D, Knee Mill Vac Pot: Cory with widowmaker hot... Drip: Bodum French Presses, Chemex Roaster: Poppers, wok, BBQ-Rotisserie...
Posted Thu May 18, 2006, 6:42am Subject: Re: Polyester felt filtering material in Aeropress
So, Scott, do you have a FP handy? Could one of these replace the middle screen in a Bodum, like a Chambourd? I use one frequently. Fines never bothered me much, but the Chemex has gotten me more acclimated to the clean cup. My one fear of a finer screen would be blow-back. But it might serve as an alternative to the Nylon fine screen at SMs, but there would be issues on how to 'seal' the center so it doesn't wallow, etc.
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