DamianWarS wrote:what tamper press do you use? is there is a particular reason why you're using a 55mm tamper in a 58mm basket or is it just the size of the tamper press?

I made myself a DIY 3D printed press when I had problems with my wrist and could not use standard tamper: https://www.thingiverse.com/thing:3367381
Looks a little bit like a toy, but works like a charm.

55mm I used only for test on this video - to check what will happen. There was a small difference in extraction, but not a disaster as some people expected. And didn't noticed taste difference - but made it only once.

I'm amazed how much 3D printing can contribute. I've done a few mods with 3D printing but I admit I'm not at point where I'm problem solving whole tools with moveable parts as a 3D printed solutions. thanks for the share, I'm might order it myself and test it out. A lot of tampers have a screw on base so it would be interesting to have something like this that can accept a screw on flat base to tamp. I know the Barista Hustle tamper is plastic with a very thin metal plate that screws on the bottom designed to be replaceable. Something like that would work well with a 3D printed tamper press

I've been using the Decent v3 Self Leveling tamper, which I think is 58.3 or 58.4mm, on a Nuova Simonelli Appia II Compact and it has been working great. The grounds that are not scraped down on the side walls were not of issue. On my Quick Mill Vetrano 2b Evo, at home, maybe because I'm working at a more calm slow pace, I noticed that the grinds that are not scraped down by the tamper, on the sides of the portafilter basket, tend to dirty the group head gasket area. So much so, that after a few shot pulls, without brushing down the group head gasket area, some extraction starts flowing along the outside of the portafilter itself. When I took the time to scrape down the residual grounds on the basket walls, I was able to pull back, to back, to back shots, with no "extraction wicking" occurring on the outside of the portafilter. Rather than taking the extra time to scrape down the grounds around the basket, with my Decent tamper, I decided to purchase a no name brand (China) 58.5mm standard tamper. I can now more quickly scrape down the basket walls, pull multiple shots, and not have to brush down the group head gasket area in between shots. I don't think the coffee taste is affected so much when comparing the 58 vs 58.5mm tampers, but rather the workflow cleanliness in regards to the group head, is more affected.

I think Decent uses IMS baskets. I've got a cheap leveling tamper from China too and it works fine. I use a puck screen and it keeps the group clean between shots so I don't worry about stuff on the walls, the puck screen is a tight enough fit that it scrapes/clean the walls when you put it in

Well, in my case it's really a huge difference, if I use the 58mm tamper I have clearly a preferential flow of my espresso around the brim, problem which is lessened if I use the 58,5mm filter! And I use a preinfusion of at least 60 seconds...in fact I will order a convex tamper to compare, it will just be one more tamper among a dozen I already tried...!

the walls of the basket are always going to mess with flow dynamics no matter what you do and there's a point where I don't think it matters much so long as it corrects itself. You can pop the puck out so you're looking at the bottom (make sure it comes out whole otherwise it doesn't work) then wait until it drys. dark areas will be where water flowed the most, light areas where less water flowed but if it's all an even colour then the flow was even. You can see this even more with paper filters the paper filter itself will have dark areas similar to the puck where the flow was the most. So it would be interesting to compare a 58mm tamp and 58.5mm tamp. I dry my pucks out all the time and usually if it looks like challenging it will show in the puck.