blind shaker : donut 58mm 57mm 54mm 51mm 49mm Flair Pro 2 (45.5mm) Flair Classic (Donut espresso shaker / donut espresso shakr)

The Donut Espresso Shaker is an espresso shaker that enables even distribution when preparing espresso for a wide range of portafilter sizes. What makes the Donut Shaker special is that it achieves this result with any portafilter size and places a strong focus on more even radial extraction of the espresso. 

Update 13.02.2025

• Labelling has been removed (‘dubios’)

• Tolerances of the underside that goes into the portafilter have been reduced for a more accurate, yet smooth fit

• The thickness of the ring that goes into the portafilter has been reduced (and the shape above is now rounded). (Measurements have shown that the thinner opening than with standard shakers makes the difference and the ‘ring’ is not necessary. - Now the result looks nicer before tamping)

The shaker was also specially developed for the 3D printing process. (Thicker walls and adapted shapes.)

Why would you want a donut extraction?

In Stéphan Ribes paper "Radial uniformity of espresso extractions" from 2020, he found that even with a donut extraction, the sides of the espresso puck are under-extracted.

Available sizes (Portafilter):

• for 58.5mm

• for 58mm

• for 57mm

• for 54mm

• for 51mm

• for 49mm

• for 45.5mm (Flair Pro2, 3)

• for 39mm (Flair Classic, Signature)

How to use:

1. Shake ground coffee in the shaker.

2. Then tap the shaker on the work surface to loosen the coffee inside from the walls.

3. Place the shaker on the portafilter, remove the lid and lift the bolt.

4. Now tap the portafilter with the shaker on the worktop (several times) or use circular movements to distribute the coffee evenly (and flat).

5. Then, remove the shaker and tamp directly

• After use, the shaker can be cleaned with a dry (barista) cloth.

• Note: With use, I had to change the grinder settings for my recipes.

• If you use the RDT method, you should use a separate cup or dry the shaker well after removing the wet beans.

• For thorough cleaning, the shaker can be rinsed by hand with conventional washing-up liquid and is ready for use immediately after drying. If possible, do not immerse the shaker in water and always allow it to dry thoroughly before storing.

Easy tips to further reduce sticking (4:34min) --- my conclusion (5:53min) --- Bolts and stability demonstration (2:30min)

How to print and what to print (read carefully to get the result shown)

PETG or PLA (use food approved if you want, study on bacterial growth in 3d printing tl.tr.: if you wash the shaker from time to time, it shouldn't be a problem with coffee)

1. Check that it is positioned as shown in the picture

2. Use the finest layer height your printer can afford relative to the time you want to spend printing or use variable layer heights to safe some time (I used 0.12 mm layer height, tolerances are optimized for that but there are also more tolerance versions)

3. No support

4. Bottom/Top surface pattern: Concentric or Archimedean Chords (looks best)

5. Enable Ironing for lid (to reduce sticking to a minimum without sanding)

6. Or print the lid with a fine layer height and Archimedean Chords (Top/Bottom layers)

• Ironing: Top surfaces,  Rectilinear (change Top surface pattern also to Rectilinear for this)

• If ironing fails or gives you a bad result, sand it (PLA should be sanded wet) or see above at 7.

1. (100% infill will give you a more “premium” feeling, but 15% is sufficient)

2. (Cleaning with cleaning alcohol can help against stuck coffee, also RDT in another cup)

Fitting problems? The bolts become smoother after being pushed into the funnel several times. There is a lid with more tolerance and the bolts can be scaled by 1-3% if fit issues occur (you don't have to reprint the funnel).

Bolt(s):

1. 6 walls/perimeters (to get a stronger layer connection)

   1. Differences and stability demonstration

2. 100% infill gives a pleasant feeling during use

3. Bottom aurface pattern: Archimedean Chords (looks best)

4. Select one of the following 4 bolts and set the additional settings:

5. Watch out by removing the bolt from the print plate. Wait until the plate has cooled down and use a scraper. (The bolts are quite stable after removal from the plate, as you can see in the video but you should not forget the leverage effect when removing it).

6. (More print settings at the end: “My further print settings”)

How to reduce sticking to a minimum:

Video: 4:34min - Remaining coffee after use and simple tips

No additional work methods:

• Clean the parts with some cleaning alcohol

• Use RDT (do it in an extra cup or clean the shaker afterwards)

• Use the ironing feature at least for the lid (see “How to print” section)

• Use a flat bolt (see “How to print” section)

Sanding methods:

• I recommend wearing a mask when sanding

• Only sand if a fine sanding tool is available (e.g. 1200 sandpaper)

• Should be sanded wet

• First sand coarse, then fine

• Then clean well (preferably with alcohol)

Why would you want a donut extraction? 

In Stéphan Ribes paper "Radial uniformity of espresso extractions" from 2020, he found that even with a donut extraction, the sides of the espresso puck are under-extracted. Also nicely illustrated here again by Lance Hedrick. 

I am currently testing whether the radial extraction yield can be improved for the Flair Pro 2 and later for other sizes.

There is also a subreddit specifically for 3D printed coffee tools where test results of this tool will be discussed in the future. We are happy about everyone interested and about like-minded people who would also like to share their experiences!: https://www.reddit.com/r/3Dprintingcoffee/ 

Tests and experiments:

Future experiment planned to test the extraction yield radial distribution.

How much coffee remains on the walls (Old Version)?

I first put all the parts together, put it on the scale, waited 10 seconds and read off the value. After use, I put all the parts together again, put them back on the scale and waited 10 seconds. Then, I read the value. After, I used a brush to spread everything into a dosing cup and weighed it again.

Here is the result for PLA-Metal like, 0.12 mm layer height and 19g beans:

Clean container: 65.2g, container after use: 65.3g, coffee residue "0g" (according to the manufacturer, the scale starts at 0.1g, but that doesn't seem to have worked here).

I also thought the result must be more but I think the blue color is very unflattering. When I painted the residue into the dosing cup, it stuck to the wall of the dosing cup and I had to paint it down first to make it look like the picture.

Feel free to contribute.

Updates:

Update 13.02.2025

• Labelling has been removed (‘dubios’)

• Tolerances of the underside that goes into the portafilter have been reduced for a more accurate, yet smooth fit

• The thickness of the ring that goes into the portafilter has been reduced (and the shape above is now rounded). (Measurements have shown that the thinner opening than with standard shakers makes the difference and the ‘ring’ is not necessary. - Now the result looks nicer before tamping)

05.04.2024

• Rounded transition to the inward sloping angle to reduce sticking

• Bolts now have small roundings between the angles to improve stability

02.04.2024:

• The inward tilt angle is now larger - this enables a significantly better user experience, especially with the larger versions

• All versions now have the same funnel, bolt and cover sizes, just different contact surfaces - so the experience should be very similar for each size (as in the Videos) and the problem of the sides being too close to the bolt is solved for the bigger versions.