mathof wrote:I would have thought that extraction evenness comes mainly from a good grinder and good distribution. Unless your basket has a truly terrible hole assortment - some holes not punched fully, others ragged and of varied sizes - the extra holes in the billet baskets wouldn't be needed to reduce unevenness, which mainly arises from channeling.

The video includes a graphic from an experiment Stéphane Ribes on the Decent forum performed. He took radial sections of spent pucks without paper filters (left) and with them (right). Then he measured TDS in immersion brews with the sections to estimate the remaining solubles.




I don't know what basket he used or what his distribution technique was but I doubt that was responsible for what he measured. I recently learned that the basket in my Robot likely does the same thing. I haven't measured puck sections but it is visually apparent, with a darker ring at the bottom where there are no holes. I don't see it with medium-dark roasts but it shows up with coffee that is on the light side of medium.

The medium-dark coffee I often pull tastes great. Could it be better? Probably. If I thought I could do it I'd buy a second basket for my Robot and drill extra holes, just to see. But I don't think I can do it.

For a few bucks I'm inclined to try the paper filter under the puck. For science.

Like Mr. Gnomer, I like the mouthfeel results that a paper filter reduces. Paper bits are not for me for a few reasons, but I get why some people like them.

The center-hole IMS screen does seem to help my Londinium produce more consistent extractions, so I use it. Similar group screen upgrades for different machines did not seem worthwhile in my experience.

Until recently, my group screen tended to get quite dirty quickly, despite regular flushing, etc. Modifying dose and basket choice has helped, but I do use a top screen for medium coffees (concerned with heat loss for lighter). Happy with the new 0.2mm Sworks.

Baskets are mostly about the coffee you're making and how fine you grind. Flow rate and shape of the sides make a difference. Personally skeptical about the latest rage of ultra-expensive baskets and one piece portafilters. Not in a price range where I'll consider them anyway, but have yet to see compelling evidence that they provide benefit past best quality $30-40 baskets, and for many coffees I prefer something simpler, anyway.

The one-piece portafilters do have an air of quality and espresso jewelry which is also an acceptable purchase reason.

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On paper filters under the puck and ss puck screens, I use the former not really for increasing extraction but rather to absorb more of the coffee oils that are extracted in the shot for health reasons - a few shots a day of espresso tends to add up quite quickly in that department. The ss screen with a filter paper disc under it help keep the puck screen clean.

As for $200 WAFO baskets and unifilters, that's a costly rabbit hole that I don't really want to go into and I don't see the point as I am happy already with what I'm getting from my lever.

I received some Weber bottom filters this week but it happens to coincide with a coffee that is new to me and which I'm having difficulty getting good extraction. So I'm in no place to even comment on the filter as I have no idea if it's making a difference.
The bottom of my puck looks like the water is channeling pretty good.