Hi Guys,

I have recently been doing a lot of research trying to get the most out of my crappy starbucks barista athena espresso machine and I have leaned a tonne in the process. I first converted my pressurized portafilter to a non-pressurized one by removing the parts that do the pressurizing. After a bit of practice I was able to get shots which were much better. Much thicker and much tastier. This was a success.

Of course I wanted to refine my technique even more so I decided to chop the bottom of the pf off entirely, so that I could see exactly how my shots were extracting. This is when things when a little awry.

I had to set my grinder about 5-6 notches finer then when I had the bottom on the pf (was about at 8, now closer to 2) to get a shot that extracts in 25-30 seconds. This is confusing to me and I cant explain why the shots run so much faster. The opening in the portafilter was about 1 cm in diameter before and now it is the entire diameter of the portafilter, could the 1 cm hole really restrict the flow that significantly?

Anyways I have finally got the shots extracting in 25-30 seconds by grinding much finer, and the look to be extracting fairly evenly, however, they all seem to taste sour. Much more so than before the chop. I have learned some temperature surfing techniques and I have measured the temperature of the water to be within the 200-205 degree range. So I am not sure why they taste sour now with the bottomless portafilter. Maybe the extra metal that I removed was contributing to extra thermal stability?

Please let me know if you have any suggestions. Thanks!

A few thoughts (assuming you're using the same beans, or close enough):

1. The change might be that you're stopping your shots at a different point then you were before. Are you judging when to stop by looking in the cup, or at the PF?

2. You might be starting/stoping your timing at different points, again it depends at what you're looking at when you're measuring.

3. It could be that the new PF is throwing off your tamping. I've got one PF that I cut myself, and it's not quite level, so I have to be careful what I put it on when tamping, I've gotten a couple bad pours because I tamped off level when I wasn't paying attention. Does the extraction look even?

My advice would be to go back to your old setting on the grinder, ignore the timing, and taste the shot, if they taste the same (and that's good), then don't worry about it

spaceman_spiff wrote:I had to set my grinder about 5-6 notches finer then when I had the bottom on the pf (was about at 8, now closer to 2) to get a shot that extracts in 25-30 seconds. This is confusing to me and I cant explain why the shots run so much faster....
Anyways I have finally got the shots extracting in 25-30 seconds by grinding much finer, and the look to be extracting fairly evenly, however, they all seem to taste sour.

It's hard to know for sure just from reading your description. But this sounds like a classic case of confusion caused by measuring your shots volumetrically rather than by mass:

1. The bottomless pf doesn't collapse crema like the conventional pf, so the extract appears bulkier
2. Since you terminate the extraction by volume, you're cutting the shots earlier than usual
3. Cutting the shot earlier means you are extracting fewer solids from the coffee
4. Extracting fewer solids ("lowering the extraction yield") skews the flavor balance towards the sour end of the spectrum.

You could try using your original grinder setting and pull the shot to a higher volume (say, 20-25% higher) than you think looks right. Taste that and compare.

When bottomless pfs first came out, numerous pro baristas were misled by their shots, just as you have been here. The cure is to cut your shot by the mass of the espresso rather than by volume (at least until you've gotten used to the appearance of the bottomless shots).

AndyS wrote:It's hard to know for sure just from reading your description. But this sounds like a classic case of confusion caused by measuring your shots volumetrically rather than by mass:

1. The bottomless pf doesn't collapse crema like the conventional pf, so the extract appears bulkier
2. Since you terminate the extraction by volume, you're cutting the shots earlier than usual
3. Cutting the shot earlier means you are extracting fewer solids from the coffee
4. Extracting fewer solids ("lowering the extraction yield") skews the flavor balance towards the sour end of the spectrum.

You could try using your original grinder setting and pull the shot to a higher volume (say, 20-25% higher) than you think looks right. Taste that and compare.

When bottomless pfs first came out, numerous pro baristas were misled by their shots, just as you have been here. The cure is to cut your shot by the mass of the espresso rather than by volume (at least until you've gotten used to the appearance of the bottomless shots).

Andy,

I think that this must be the case. The shots do have a lot more crema, which means there is a lot more trapped gas inside the shot so the shot would be much less dense. In fact the shot tends to foam up like a beer from a keg.

I am probably only really getting the first 3/4 of the extraction. I will try pulling longer shots with a coarser grind.

Thanks for your response.