I either get a high flow - quick shot or, when going finer, I have to use severe hand force to get to 4 bars and still not getting a proper flow

It sounds like you need a grind between those two end points...but if that's not possible I think what I'd try is the finer grind but just apply consistent low (2 bar'ish) pressure until you start to see drips in the bottom of your cup then I'd lean into (or even over) the Robot to ramp up pressure until you get the volume/ratio you want. I wouldn't worry too much about the timings for now; I'd just focus on getting a shot that tastes/feels good.

mixespresso wrote:...when going finer, I have to use severe hand force to get to 4 bars and still not getting a proper flow

Was that a typo? Did you mean 14 bar?

Weird thing is that it is hard for the op to press when the gauge only states 4 bars, but then again... how does one interpret soft/hard. Maybe I am pressing much harder when I get up to 8 to 9 bars. If you press harder does the gauge go up with flow remaining the same?

A while ago I posted a link in this thread to a robot manual that has the bathroom scale equivalents for the bar readings on the gauge, try a shot by comparing the gauge and the bathroom scale readings to see if the gauge is close to where it should be. Pointing a video towards one reading while reading out loud the other helps. Problem with using a digital scale is that it will most likely lock during preinfusion as the reading remains constant enough to lock the scale, so perhaps just try a shot without preinfusion to test it.

One thing I learned after over a year of using the robot is that the speed at which you get up to the desired pressure when pressing the levers, both for preinfusion and the ramp up to shot pressure, makes a huge difference in shot timings and pressure. I found that if you press really fast to my desired pressures the shot will run significantly longer and at a higher pressure than if ramping up slower. Not sure which is better as there are a lot of variable, but I have found that once I maintained the "same" speed the shots were more consistent shot to shot. I am thinking that pressing faster creates a quick downward pressure which compresses the puck more? Just guessing...

Jonk wrote:Sounds like you just need to grind finer? You should be able to completely choke the Robot if you want.

One thing to keep in mind is that pre-infusion and how you ramp up will play a big role in resistance/flow. For example if you do manage to barely choke the machine without pre-infusion, the same grind will pull fine if you pre-infuse until you have beading all over the bottom of the basket before applying your desired pressure.

that is an interesting test to try: choking the robot without preinfusion first. Then using preinfusion, less pressure and same grinder settings. thanks

mborkow wrote:It sounds like you need a grind between those two end points...but if that's not possible I think what I'd try is the finer grind but just apply consistent low (2 bar'ish) pressure until you start to see drips in the bottom of your cup then I'd lean into (or even over) the Robot to ramp up pressure until you get the volume/ratio you want. I wouldn't worry too much about the timings for now; I'd just focus on getting a shot that tastes/feels good.

Something it has confused me a bit is that I aim for a 2 bar'ish preinfusion , but I see the drippings at 12 bar'ish.

I admit that I have got so used to using a scale and a timer that I felt "unprotected" using the robot without it. I can not fit my scale on the tray but I do use my phone timer. So yes, less focus on timing is good I think. I need to learn how to control the flow first

jpender wrote:Was that a typo? Did you mean 14 bar?

I meant that the goal is ramping up to 6 bars, but I cannot go beyond 4 bars without using lots of force

Ken5 wrote:Weird thing is that it is hard for the op to press when the gauge only states 4 bars, but then again... how does one interpret soft/hard. Maybe I am pressing much harder when I get up to 8 to 9 bars. If you press harder does the gauge go up with flow remaining the same?

A while ago I posted a link in this thread to a robot manual that has the bathroom scale equivalents for the bar readings on the gauge, try a shot by comparing the gauge and the bathroom scale readings to see if the gauge is close to where it should be. Pointing a video towards one reading while reading out loud the other helps. Problem with using a digital scale is that it will most likely lock during preinfusion as the reading remains constant enough to lock the scale, so perhaps just try a shot without preinfusion to test it.

One thing I learned after over a year of using the robot is that the speed at which you get up to the desired pressure when pressing the levers, both for preinfusion and the ramp up to shot pressure, makes a huge difference in shot timings and pressure. I found that if you press really fast to my desired pressures the shot will run significantly longer and at a higher pressure than if ramping up slower. Not sure which is better as there are a lot of variable, but I have found that once I maintained the "same" speed the shots were more consistent shot to shot. I am thinking that pressing faster creates a quick downward pressure which compresses the puck more? Just guessing...

Yes, it is very weird. I wonder if I am unconsciously pressing unevenly with the 2 hands. When I get to 4 bars I get significant resistance, but the robot does not choke and I get a very unpretty flow with no sign of a properly centred cone.
Yesterday, as a test to see if the grinder was acting up, I tried a shot with the DeLonghi using the same grinder settings and I got a decent flow/cone

Yes, I'd like to test the gauge with the scale.

I have to be doing something wrong. I will buy more beans tomorrow and I will shoot a video which I hope will reveal a flaw in my technique

Thanks everybody!

mixespresso wrote:I meant that the goal is ramping up to 6 bars, but I cannot go beyond 4 bars without using lots of force

That's really weird. To achieve 4 bar you only need to press down on each arm with about 10lbs of force. That should feel pretty easy unless you have some physical limitation.

If the Robot is really "stuck" at 4 bar it would indicate either a mechanical problem or a pressure gauge issue.


Who knows? Maybe your forthcoming video will be revealing.

My pre-infusions usually happen at around 1 bar, which also feels weird to me. I have no experience so it is hard to follow my own judgement yet, but my understanding from watching videos is that it commonly happens at 2'ish bars

I will get a video this week. Cheers

You don't need to aim for a specific pressure during pre-infusion. Just make sure it's low until you can see even beading underneath the basket. It's okay for a few grams to drip until you raise the pressure (from say 0-2 to 4-8) - it's more important to have even saturation of the puck if that's what you're going for. Skipping pre-infusion also has merit, you need to develop a feel for the different kind of profiles you can use. Great thing with the Robot is that you can adjust on the fly.