Puck screen thickness

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boren

#1: Post by boren »

For some reason 1.7mm is the most popular puck screen thickness. After trying various puck screens, ranging from 0.2mm to 2.0mm my conclusion is that the thinner the better. I don't notice any significant difference in water distribution, but the thinner puck screens have several advantages:

1. Minimal thermal impact due to lower mass.
2. Minimal impact on basket headspace.
3. Easier to clean. The 0.2mm puck screen uses holes, similar to a basket, so it's easier to clean than the mesh/weave pattern of thicker screens which tends to collect more coffee particles (and even more so the thicker the screen is).
4. Easier to check if the screen is clean. Just look at light source through it.

Bottom line: In puck screens, 0.2mm > 1.0mm > 1.7mm > 2.0mm :-)

BaristaBob

#2: Post by BaristaBob »

I don't doubt your conclusions, but do you have any EY data to further support those conclusions? I realize these top screens have not been shown to change EY much, but hope springs eternal.
Bob "hello darkness my old friend..I've come to drink you once again"

boren (original poster)

#3: Post by boren (original poster) »

@BaristaBob - I don't have EY data, but I don't think it's needed to illustrate the three benefits I mentioned, for sure not the last two.

Can you theorize what could be the dynamics that would lead to significant change in EY due to puck screen thickness? I find it hard to imagine. After all, given the same pattern and density*, water reaches the coffee bed in as many points at once, regardless of the thickness of the screen above it, no?

* The 0.2mm puck screens use a different pattern, so for the sake of discussion let's focus on 1.0mm weave pattern vs thicker pucks screens of the same pattern.

Pressino

#4: Post by Pressino »

One thing I can imagine is that the puck screen spreads out the water to contact the puck more evenly more evenly than the shower screen alone, leading to greater extraction as the water migrates down the puck. Just a guess & would be easy to check with refractometry...I may just try that.

Pressino

#5: Post by Pressino »

I did try the above experiment, using the same coffee (Lavazza), grind setting (on 64mm Mazzer mini burrs), dose (16.8g), puck preparation (WDT, level/tamping) and coffee output (31g in 31sec), on the same machine and PID settings). Used 1.7mm Normcore for the puck screen. Brix measurement of extracted espresso was 12.2 with screen and 10.9 without).

I did zero the refractometer before measurements and check again afterward.

Will continue repeating this experiment for a while, but so far the results indicate an increase in Brix/TDS extraction with use of the puck screen. There are other posts that report no significant change in EY with screen use, but IMO there is an increase and furthermore there is a plausible reason for this to occur (what I said above).

boren (original poster)

#6: Post by boren (original poster) »

I fully expect any puck screen to improve extraction a bit. What would be more surprising is to see clear and repeatable differences between different puck screens.

Cartmarn

#7: Post by Cartmarn »

I've recently made a really thin puck screen. It's thickness is about 0.2mm. Also experimenting with dual-layer structure (with another layer of mesh screen) to keep shower-screen absolutely clean.

original 0.2mm thickness


dual-layer version

BaristaBob

#8: Post by BaristaBob replying to Cartmarn »

Is this dual-layer screen an item for sale? Just wondering...I'd like to do some comparison testing versus my 1.7mm screen.
Bob "hello darkness my old friend..I've come to drink you once again"

Cartmarn

#9: Post by Cartmarn replying to BaristaBob »

Hi, Bob. It's available in China. Would be glad to give you a piece. I'll check with the mail carriers and see if there is a reasonable price.

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Ursego

#10: Post by Ursego »

I am happy with espresso paper filters. Bought 1000 pieces for a few bucks. Zero maintenance efforts. :mrgreen: