Aeropress - better with paper or metal filters? A practical test.

Coffee preparation techniques besides espresso like pourover.

#1: Post by canto »

When extracting with the Aeropress, the metal-filters should permit the transit of more solid substances. Does this correspond to a more interesting taste?

A coffee school of Florence, the Espresso Academy, we collaborate with, organize every month an evening with several coffee experiments.
One of the last was about a very cool and new tool of the coffee brewing world: the aeropress. For the extractions with this tool are often used two kind of filters: in paper or, growing and growing on the market, in steel; but, putting aside the practical advantages and disadvantages, which system is preferable?

In Florence they would to try. In the experiment was used, for both the extractions, the same coffee, the same water with same mineral contents, the same temperature of the water and the same brew ratio. Only varying the kind of filter used: a paper one in the first case, a metal for the second trial.

The benchmarks we used:
15 grams of coffee
190 grams of water at 92°
A preinfusion lasted 30 seconds with 30 grams of water
after the addition of 160 grams of water , wait 60 seconds before creating a turbulence
Press in 20 seconds.
The extraction in both cases was obtained with the inverted Aeropress method that we mentioned in this post.

Let's come to the results. As a general idea, a metal-filter should let more substances pass through, oils contained in the coffee included,making our extraction richer.

Among 4 tasters, two were already comfortable with filter-extractions and two tried this type of extraction a for the first time. impressions were:

1) paper filter: low bitterness,medium body,high tartness and fine aromatic notes,very similar to a v60 extraction
2) metal filter: stronger fruity aromas,low tartness, strong body,sweeter taste; more similar to a coffee prepared with a moka and the most appreciated from our tasters.


#2: Post by CathyWeeks »

This is a really wonderful test! Thanks for sharing! I've been considering getting a metal filter for my Aeropress, but I don't use it very often (maybe every week or so) so I haven't bought one yet, preferring my glass and metal brewing methods.

I had to laugh - you called the Aeropress "new". It was invented in 2005, so it's been around for 11 years. But, I suppose that is a mere infant, compared to say ... the moka pot. :-)

It's all a matter of perspective, I suppose. (My two favorite brewing methods have been available for six years (Sowden Softbrew) and less than one year (Duo Coffee Steeper) respectively.

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#3: Post by drgary »

Also, Gabriele, here is some background information for you. The Aeropress inventor, Alan Adler, does not sell metal filters. He uses paper filters based on research that filtering coffee through paper almost entirely eliminates chemicals in coffee that can raise cholesterol and triglycerides. For a time I followed his advice and used paper filters in my espresso machine filter basket also but have since decided to "live dangerously" and brew my espresso as originally designed.

The effect of espresso drinking on cholesterol

What I WOULD do for a good cup of coffee!

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#4: Post by galumay »

Was the tasting blind? (not that it would be statistically significant with such a tiny sample.)

Would be interesting if someone did the same experiment with blind tasting and a sufficiently large sample so as to be meaningful.

I use the steel type whenever I use the Aeropress because its less messy and I dont have to buy filter papers!
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#5: Post by happycat »

Couple of points.

I used to brew with metal for years but now prefer paper because it's easier to eject the puck into garbage, esp when travelling. Haven't noticed any taste difference but didn't do anything scientific.

You need to explain the protocol in more detail. Were the two samples tested with sipping and spitting? Were they tried randomly by the group (eg some got steel first and some second?) taste changes the more you drink and the cooler the coffee is.
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#6: Post by jpender »

Which metal filter was used?

canto (original poster)

#7: Post by canto (original poster) »

We made a blind test using some cupping spoon to taste like we do in cupping session. We prepared two cups at the same time and we taste them at different temperature.
The metal filter we used was the IMS filter Superfine



#8: Post by Trimethylpurine »

galumay wrote:Was the tasting blind? (not that it would be statistically significant with such a tiny sample.)

Four tasters can give statistically significant results if, a) the means are sufficiently far apart, and b) the variance is sufficiently small.

However putting numbers on taste tests is fraught with difficulty.

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#9: Post by happycat »

Statistical significance is not really meaningful without effect size :lol:
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