most baskets hole patterns are not edge-to-edge (the unifilter might be the exception). so essentially there is a wall of coffee along the edge that when water passes through does not have a direct exit and needs to migrate inward to reach an exit path. This essentially means the outer holes get more water passing through them and because of this you would think that donut shots should be expected. To compensate for this you'd have to somehow restrict the flow on the sides or increase the flow in the middle (or both) so that the water meets the holes all at the same time making a nice pretty shot but is this really best practice?

The spent puck will tell the story and if the puck has a dark outer rim that's the donut you don't want. Dark areas in the spent puck indicate under-extracted areas and if you look at a cross-section the dark spots will be a few mm deep in the puck indicating areas of the flow that were favored less. a dark rim around the puck indicates an under-extracted rim and the center may have had extra flow that would may lead to over-extracted areas. The goal is a consistent color throughout indicating that water spent the same amount of time through each part of the puck.

I can achieve that goal with good puck prep, even tamp, WDT, paper filters, puck screens, etc... but they are not Instagram-worthy shots. they typically are donut shots and are thinner with less crema (because of the paper filter) but the spent pucks look perfect and the shots are more consistent.

yes

I can eliminate donut extractions by doing WDT and grooming the puck with my WDT tool (a mini whisk) so there's a slight depression in the middle and the edges rise slightly. I insert the tamper and apply pressure in a circular fashion around the edges to seal them, then press straight down with full tamp pressure.

Something similar can be done with a convex tamper. I've tried that and it works, but the above technique is more effective.

Note: I drink singles almost exclusively and developed the technique for single baskets. Back when I drank doubles, I did WDT, groomed the puck with a BT Wedge and tamped evenly at full tamp pressure. That worked OK. Didn't get donut extractions, but did get some blank areas on VST baskets toward the end of the shot.

As to whether my singles taste worse than donut extractions, I can't say because I haven't tested that. I'll do so at some point...

Peppersass wrote:I can eliminate donut extractions by doing WDT and grooming the puck with my WDT tool (a mini whisk) so there's a slight depression in the middle and the edges rise slightly. I insert the tamper and apply pressure in a circular fashion around the edges to seal them, then press straight down with full tamp pressure.

Exactly my point. You have to manipulate the grinds so they are uneven to not get a donut shot. Perhaps a better-looking shot, but that doesn't sound right and it also doesn't seem like the result will be an even extraction.

I noticed today that, indeed, the circumference of the spent puck is darker than the rest of the puck, presumably indicating that region is under-extracted. Tomorrow I'll try a flat distribution and see what happens.

Extraction of the outer ring is a challenge, particularly if the perforations in some baskets stop short of the outer edge. Some DE1 users have shown that filter papers top and bottom, as well as, a slight mounding of the grounds can help.

I've been dissecting the pucks in my knock box for the past couple of days and haven't observed any signs of "donut" puck extractions. I single dose into a grounds catcher cup, perform a "paper clip" WDT, tap the portafilter once or twice to settle the grounds, then level and tamp with one of those $25 Amazon leveler/tampers and extract the shot. Looks perfect coming out of the naked PF and tastes great. Maybe I got donut pucks when I was using a doser and before I started the above puck prep routine (and my naked PF extractions looked messy), but I certainly haven't seen any evidence of donut pucks currently.

John49 wrote:Extraction of the outer ring is a challenge, particularly if the perforations in some baskets stop short of the outer edge. Some DE1 users have shown that filter papers top and bottom, as well as, a slight mounding of the grounds can help.

I use HQ21 ridgeless primarily, it's nigh impossible to not get donut extraction. Those are large baskets both volume and size (width). I've checked with calipers. Even a 58.5 tamper fits loose, that same tamper in a VST damn near jams and gets stuck. With a paper filter, still Donuts even on the BDB and slowly infusion at low flow and like 2 bar lol.

Love those baskets though

Aren't EP HQ21 and other similar baskets were purposely designed to unevenly extract the puck?

So that there's a ring of grinds with lower extraction to balance a shot with darker roasts?

Not sure, but I can say after 10+ years and side by side the HQ21 beats the VST20 easily for taste imo, no matter dose, roast, origin/blend, profiling, anything from a Vario to Monolith Flat etc. I'll pull the vst 20 out once in awhile and put it right back in the drawer, something always taste kinda off with it and always an astringent or really acidic like note. Like I'm pulling a light Burundi right now that's a strawberry wallop, I tried the vst 20 like 15 times and adjusting all around and since it's a fast flow basket kind of turbo shots as well and mehhh, on the HQ21 strawberries for days pulled longer or even ristretto.

Someone other week mentioned how the vst 20 flows far faster than other vst baskets. I have 15 and 18 but their packed up. But I guess makes sense, I've never liked the way that basket flowed or tasted lol. But that was the 1st time all these years saw someone mention how the 20 was designed to be even faster flowing than the 15/18. I don't recall the 15 or 18 being finicky or issues like it that's for sure. I honestly don't really use the HQ14 either since the 21 is such a good and forgiving basket of dose and bean type, I was at 18, 22 and 21g on the last 3 different beans.

Edit - actually I think it was you that was mentioning that? Lol