Hi,

I have a Pro 800 and drink mostly medium roast since I bought the machine.

I pull the lever and let it be there anywhere between 2-14 seconds. During this time of pre-infusion, there are no drops and the portafilter barely shows any signs of liquid coffee saturating it.

Is this normal?

If I grind any coarser the flow rate will increase too much.

Once you decide to end preinfusion and raise the lever, how long does your shot take?

I did not time that, I'll check this out and report back.

Yes, grind slightly coarser.

On an Europiccola, the rule of thumb is to dial in the grind to the point where preinfusion drips (a drop or two) at about 8-10 seconds. (But also! time to drips is highly dependent on head temperature.)

If you can't get grinder setting in between no drips and a rate of flow that is too fast...sounds like a grinder problem to me.

How much head space between top of puck and shower screen: Before brew and after brew?

The thing is, on the latest attempt it seemed as if the grind is too coarse judging by the flow rate (I may be utterly wrong here, maybe I'll upload a video for analysis), and yet there are no drops during the PI phase.

I grind 14g in the stock (pro800) double basket. I was dosing 18g and slowly lowered the dose. There were no drops with higher dosage either.

I don't know about the head space. What can it tell? (Learning here...)

Headspace 411 & a couple of methods to determine proper headspace:

This one is somewhat typically used but not one I use: Dry puck, before brew place a nickel coin atop the puck, insert as usual into the group head, remove and notice how much distance, if any, the nickel pushes into the puck. The downside with this method is that it doesn't take into account the vertical bloom of various beans/roast levels, etc. But its a starting point I guess.

The other way, the one I rely upon, is to look at the puck AFTER you pull a shot to see if there is tell-tale indentations from the shower screen holes. What works best on my Slayer, but may not be perfect for you: After shot pull I have light indentations from the shower screen. This tells me the puck expanded during PI and the shot pull just enough to rise up to the shower screen and no more. If the indentations appear heavy/very pronounced this tells me to lower the dose and, all things being equal, grind finer or run the shot ratio longer (taste defines whether you go one direction or the other...).

Generally, but is machine dependent, the more headspace between the expanded puck and the shower screen, the more you will get significantly faster rate of flow once the puck is fully saturated. More often than not, too much headspace results in diluted espresso flavor; under extracted. Whereas, if there is inadequate head space for the puck to fully expand, it will alter the pull conversely, much slower rate of flow throughout the shot pull, and flavor will be compromised.

Lastly, the density of the respective beans and/or roast level will effect how much "bloom" you get in the bean puck (as well as length of pre-infusion). For the beans I frequently use/order, I take copious notes about all the perimeters as well as tasting notes so that I can shortcut the process months/orders later.

Also, again depending upon the specific bean and roast level as well as taste, I don't always run PI to first drips. Sometimes I find the resulting flavor too compressed and without good separation of flavors. So, I will figure out through trial and error, how many seconds I need for PI before ramping up the pressure for the shot.

It all comes back to being able to taste what is going on with espresso pulls. W/o this knowledge you'll be chasing without much predictable success. Per other threads, if you are relatively new to espresso making, it is a wise and prudent investment to hire/pay a good barista to help you understand flavor notes. This will accelerate the process, eliminate much wasted coffee beans & time, and get you to much more predictable results in the cup.

Thanks for your valuable input.

I tried playing with grind settings, using 16g doses, then did some more experiments with 14g doses. I don't seem to be able to find this balance between some drops and a reasonable flow rate.

However, I went through numerous YouTube videos of Profitec 800 making shots, and most of them, at least from the vids I watched, appear to behave the same as mine machine. Why is that? maybe I should let that go? maybe it isn't an indication of a bad prep, isn't it?