Ok, so I was messing about with my french press. Check out the video below. I will say, numbers aside, for me the result is closer to the cleanliness of a vacpot with say a glass filter, that is to say not as clean as cloth or paper, but not unpleasantly dirty….
Worth a try perhaps…
I used 30g (coffee) / 500g (water)
and where I say – “middle part” – should say “top part”…
Excellent idea David!
Did you try using a paper filter (v60 or Chemex) instead of the clingfilm? I guess it would rip more easily…
I’m going to try this right now!
—Tumi
I did try using a siphon cloth filter once… Results were poor…
My understanding of the benefits with a metal filter is that all of the volatile solids remain in the solution, rather than getting stuck in the filter as they do with paper or, to a lesser extent, cloth. This results in a fuller mouth-feel and deeper, less acidic notes (at least in theory and my small experience).
While I understand that you already tried the paper filter, it’s surprising to me that the taste remained unchanged. With a plastic film, the volatile oils shouldn’t be caught by anything, like they would be with paper or cloth. I understand that cutting holes in a paper filter would allow some oils to pass through, but to my mind it makes sense that the filter still plays a large role.
In terms of trying to make the press cleaner, I’ve tried putting the coffee on top of the filter then pulling up. It did result in a slightly cleaner cup, but man was it a chore to do. Cleanup was…difficult.
Yea, the chemex filter didn’t do brilliantly either. Looks and tastes exactly like french press.
Alas, my computer is too old to stream Vimeo. Flash 10 is completely inoperable on iBook G4s. Wish I could see it.
In any case, I’d like to bring back up my press pot method: http://bitterpress.com/2010/03/06/experiments-reclaiming-the-press-pot/
I’m a huge fan of the Cafe Solo, and this really helped mimic the body and lightness that you can get from it without the cost of a fancy Danish design firm.
You can download the original file from the Vimeo page… http://vimeo.com/14023197
Will try your method later – but I’m not an enormous Cafe Solo fan (apart from to use as a nice jug).
I made a one cup brew of 200 gr water to 12 gr coffee ground coarse in one of the smaller presses. The Aeropress filter fits perfectly in the plunger.
Made a very fine cup too. Visually, there’s almost none of the foam you usually get in a french press. It still leaves some of the body in the cup, like the cloth filter.
Does it affect taste? I would think that the plastic would melt and affect the coffee.
With the brand of clingfilm I used – I could not perceive a taste attributable to the film. The melting point of clingfilm, as far as I know, is around 120C (open to correction on that, but I haven’t melted any with water or steam).
Hi David,
First, thanks for recording an elegant method for solids analysis. I’ll be employing a variant of your methodology in an upcoming study of multiple French press brew beds. I’ll be sure and mention I learned the technique from you.
That said, my research suggests there is room for concern about the effects of polyethylene film immersed in hot coffee. I began studying the problem of plastic leachates a few months ago as a part of our company’s French press design process, and I was sufficiently concerned by my findings to recommend that plastic contact with hot coffee be avoided altogether.
Potential toxicity stems from leachates rather than melted plastic per se. Actually, raw polyethylene melts at 80 degrees C, so other chemicals are added to increase melting temperature.
Studies of polyethylene leachates do confirm that leaching occurs, but no studies I could find have been done on the exact effect of particular temp levels or pH levels on leaching rates. Studies of leachate toxicity are suggestive, but not yet conclusive.
Here are two links I found most useful.
Polyethylene Terephthalate Migration and Toxicity:
http://www.mindfully.org/Plastic/Polyethylene/Polyethylene-Terephthalate-Sheftel.htm
Toxicity of Water Stored in Polyethylene Bottles (older, but interesting)
http://www.jstor.org/pss/2484874
I’m not sure about EU regulations, but in the United States, the FDA does not closely monitor the introduction of plastics into the market place. Companies are expected to do their own due diligence on plastics safety within federal guidelines, and FDA only becomes involved in case of a complaint.
Hopefully this is useful to you. Thanks again for the demonstration of an accurate, simple insolubles measuring process.
Nate
This looks interesting and I will definitely give it a go.
How long did you brew for? I tend to brew for around 3 min for press pot.
Well, it looks like getting a finer sieve, or grinding at a coarser setting would have a similar effect. But, a ‘cleaner’ cup can be achieved with a pourover, aeropress, espresso machine, mocha pot! I think the french press has lasted so long because a lot of people enjoy the full body and oily cup, I know I do most of the time, especially when it’s a good coffee.