zak42 wrote:This totally sounds like the MiniE distribution problems I mentioned earlier, the flow seems to start at the back of the basket and move to the front.

Yes, it appears that I indeed experience the same thing. I tried to turn it right and then left and it cured backflow. Unfortunately, it didn't have any noticeable effect on the taste But I think that's something I just need to keep working on.

malachi wrote:It's not the grinder.

The extraction issue you're seeing is related to your distribution. Suggest two things.

1 - rotate the portafilter from left to right and back again while dosing.
2 - Stockfleth's for distribution (with pressure).

Well, I agree with you but my view is - it is the grinder deficiency that could be elliminated to a proper technique. Which I will keep working on. Unfortunately, I don't quite understand Stockfleth method. The only video I have seen is very small and hard to see.

In addition... you're getting way too involved (chopping, using a knife to break stuff up). Keep it simple. Seriously.

Well, I just wanted to experiment. It's not something I plan to do again. I measure the temperature while doing hx cooling flush by snaking k-type thermocouple into the single cup portafilter. And in general I do the cooling flush to get to the target temp although I must admit it's probably pretty far from ideal due to my lack of experience.

finally... it doesn't matter what it looks like if it tastes good.

I said it tasted ok but there was still considerable bitterness. So instead of molten chocolate, it more like molten chocolate with some ashtray aftertaste

Anyway, thanks for the help everybody. I'm still not there but I see the light at the end of the tunnel. I'll keep working on my technique and try to master Stockfleth move.

HB wrote:Tapping while you dose settles the grinds, resulting in more coffee in the puck (and thus a coarser grinder setting). I'm not one to argue with good results, but How do you explore the extraction space? offers some thought-provoking suggestions and Chris' blog entry Learning suggests concrete steps. My #1 priority is consistency, and of course avoiding bad habits that disturb the results of the good habits (e.g., excessive rapping the portafilter to knock down loose grinds when tamping, which can break the puck's adhesion to the basket and cause side channeling).

You and Chris were correct. I adjusted my grind finer and now only tap at one point and I'm getting 2oz in 27 seconds give or take. Good links as well.

Thanks - Michael

HB wrote:I was thinking the same thing and wondered (a) what's the brew pressure? and (b) what coffee is CoffeeAddict using? The Giotto Premium that I evaluated was initially regulated pretty high; see Help Me Adjust Overpressure Valve on a Giotto Premium for instructions. Unusually high brew pressure and short volumes mean a higher risk of channeling. Lowering the max brew pressure to a more manageable 8.5 bar might help.

I finally measured the pressure and it's 10 without the flow. Do you think it's worth going through the trouble of opening the machine to lower it?

It took me longer to remove the Giotto's case than adjust the OPV, but yes, I would lower the pressure, especially if you pull ristrettos.