I can't help but think that, in the time you have spent on the sysiphean task of making acceptably mediocre strong coffee with a pressurized portafilter, you could have mastered the basics of making excellent real espresso with a real portafilter.

I already depressurized the basket and start experiments with real espresso and grinding and all that staff and frustration have already begun

Excellent

Today i changed the beans and cleaned the grinder very well purging all the residuals inside,,, well,,,things changed .

The new beans i already know it's taste very well because i always drink it at the cafe shop, the beans are oily inside the bag which is a good indication i think.

The first observation was it is more dense, same grind time gave over dose.

Though it is brown roast it gave a lighter brown color when grind than previous coffee.

And... Same grind size chocked my machine , the first drops came out after 10 sec and only continued to slowly dripping, slight dark crema was there, after maybe 10 sec later the flow speed up a little ( also drops) ( but i think due to channeling because later i saw two small holes in the puck ),, anyway, i continued the drink with milk, i was expecting a horrible taste but to my surprise i liked the taste (maybe because i have spent the last week drinking very bad shots), actually i am still training my self to describe the taste, but i am sure that there was no bitterness at all, it was strong, maybe acid, but with milk at least i tatse and feel a coffee drink, i liked it, it was strong but that did not bother me, i am happy to see at least a different result even if it is not the best.

Tomorrow i am going to buy a new metal tamper instead of the plastic one.

Just pulled another shot, but down-dose to 12.5g because 14g hit the shower screen (dont know why) and tamp with moderate pressure untill i feel the tamp no longer move down any more.. And i think i got a good result, only crema is dark, what makes it dark?
Please judge the shot..

So....
The more i grind, brew, taste and observe the more i discover more details, and i hope you guys share your knowledge and experience with me to save me time and money and frusteration..

My dose now is very limited..., why? mmmm
The double basket takes 14g of pre ground coffee, i load it, tamp it, and it hits the shower screen pretty much, looks fine for a pressurized basket, but things change with non pressurized.

First of all, i know the coffee should not touch the shower screen because while locking the portafilter in and rotate it will break the surface of the puck and cause channeling, so i must not do that,, ok
Secondly, the fine fresh ground coffee takes more space/volume,, the same amount of freshly ground fine coffee of 14g is high enough to make me tamp it really hard to press it down and still hit the shower screen badly plus that hard tamp shocks the machine.

So, my only choice is to bring the dose down, i found 12.5g doesnt hit the shower screen.
Am i on the right track? Should i fix this dose and start tweaking (tamp pressure, grind size, maybe more downdose with coarse grind), at this dose the shot takes 45 sec, about 55-60g depending on tamp pressure, taste is little annoying, no bitterness but bland taste with unwanted flavors, no sweetness at all.. The shot exactly like in the video, crema still dark and bitter.

Kemo_88 wrote: So, my only choice is to bring the dose down, i found 12.5g doesnt hit the shower screen.
Am i on the right track? Should i fix this dose and start tweaking (tamp pressure, grind size, maybe more downdose with coarse grind), at this dose the shot takes 45 sec, about 55-60g depending on tamp pressure, taste is little annoying, no bitterness but bland taste with unwanted flavors, no sweetness at all.. The shot exactly like in the video, crema still dark and bitter.

You're definitely on the right track! Your results look a lot better now.

Some coffees are less dense than the others (that's why some coffee are fine with 14g dose and some not). As you suspected, you don't want the coffee to hit the screen or else it will cause channeling resulting a bad pour.

This is what I would do: Keep the tamp pressure and dose (12.5g for this coffee) constant. Try to keep the extraction time constant as well. Vary the grind setting only, to aim for roughly 25-30g coffee in the cup in about 27-30s (counted from the moment the pump being turned on).

The crema looked dark with pale spots because the grind was slightly too fine, and the extraction time went too long.

I am not sure about your coffee selection or what are the coffees available to you. If the current coffee is not to your taste (or not up to quality), it will not taste good no matter how you tweak the extraction process. That is to say if after all these optimization and you still find the coffee unsatisfactory, it's worth looking into buying a different coffee (just like cooking, your dish will be limited by the quality of the ingredient that you use).

Thanks,, really appreciate your reply..

Now i am getting about 60g in the cup in 45 sec.
So if i manually stopped the shot at 30g in the cup the time will be pretty close to 22-25 like you say, but you sat it is a little long extraction, so i need to go coarser which will through away the rule you said.

But i think the goal is not by time,, there is a good signs of espresso, and if those signs are fulfilled away from the time rules, so be it, right?, depending on coffee and machine and pressure and also basket,, my basket is not straight down, it is tapered, i am sure this will have a rules of its own.

Today will try go a hair coarser and see...

Bought a metal tamper, size 57, took it to a lathe to bring the size down, the basket is 51.5mm, i made it 51.3mm,, i feel it very tight.

Do i have to make it that tight or give it more clearance?,, does it make a difference?

Bevel the edge away from the bottom edge, and there will be less tightness and suction, despite close fit.