Isaac wrote:I'm not sure if I'm just an incredible weakling (entirely possible!) or not but it seems to get the 6+ - ~8ish bars of pressure I'm having to grind pretty finely but also it requires a lot of effort on my end -- certainly more than it seems others are exerting in videos. I'm coming away from shots with the robot's hands indented into my own hands and it kind of hurts. Just wondering if this is normal or I need to hit the weights.

Beginners tend to follow the formula to get the best shot for a particular coffee. Someone told me long ago, let the machine teach you its sweet spot. If your grind is so fine you have to do a downward bench press, you're grinding too fine. The Robot was originally conceived as a simple, analog device without a pressure gauge. I believe people get away from the lever experience by overthinking it. For the flavors of coffee you like, set a grind that's comfortable for pulling a shot. Don't measure success by getting 8 bars of pressure.* Adjust the dose and the grind for a similar feel and adjust temperature to dial in the shot. Keep it comfortable. Maybe even ignore the seconds ticking away. If your pull is 25 or 35 seconds, will you really taste much difference, all else being the same?

I recall seeing something about the designer, Paul, pulling many shots at some expo event at much less than 8 bar. I agree with Dr. Gary and others that have posted - I don't focus on a specific number, I go mostly by flow. If I am having to muscle through a shot, next time I grind coarser. If things go too fast and easy, next time I grind finer. Between those, the window is fairly wide for tasty espresso (given a nicely capable grinder and good fresh beans).

thirdcrackfourthwave wrote:I don't know why Hoffman measures the 60 grams of water going in. Just fill it to where Paul Pratt suggests. The important amount of liquid is what ends up in the cup.

He didn't have a scale that would fit the Robot. So he worked it out by experimenting with how much water would result in a particular weight in the cup if you push all the water through.

The problem with his approach is while you're weighing the water it's cooling off. I like Mr. Hoffmann but he had some weird ideas about thermal loss in that video.

MB wrote:I recall seeing something about the designer, Paul, pulling many shots at some expo event at much less than 8 bar. I agree with Dr. Gary and others that have posted - I don't focus on a specific number, I go mostly by flow.

6-7 bar is the number stated in the manual, I'll bet mine are often less than that.

ojaw wrote:I still don't think that's the issue though because my flow varies with my untimed infusions and somewhat changeable (on purpose) pressing of the arms.

Sure. Preinfusion, grind fineness, pressure -- those all affect flow. But the "spatters a bit to the sides" issue sounds like some type of uneven flow. I'd love to see exactly what you're talking about as I'm not sure I've experienced it.

ojaw wrote:6-7 bar is the number stated in the manual, I'll bet mine are often less than that.

I usually aim for 7 bar, sometimes it's 8. Sometimes it's 6. When it's less I grind finer.

I'm not particularly strong, although I sometimes smell that way.

Too much information?

jpender wrote: Sure. Preinfusion, grind fineness, pressure -- those all affect flow. But the "spatters a bit to the sides" issue sounds like some type of uneven flow. I'd love to see exactly what you're talking about as I'm not sure I've experienced it.

I'm terrible at video but maybe at some point I'll give it a go.

Javier wrote:The Robot in white (cream?) looks incredibly nice.

It does! My Robot lives in a '40s-era kitchen with a green and cream color scheme. It seemed nigh certain(*) that the green Robot was going to clash with the existing greens, but the cream Robot is both amazing in its own right, and goes wonderfully with the kitchen.

(*) color on the internet being the mess that it is.

jpender wrote: He didn't have a scale that would fit the Robot. So he worked it out by experimenting with how much water would result in a particular weight in the cup if you push all the water through.

The problem with his approach is while you're weighing the water it's cooling off. I like Mr. Hoffmann but he had some weird ideas about thermal loss in that video.

Okay, I agree in that it is a reasonable-ish explanation but there are some problems: 1. Your mention of thermal loss is spot on, 2. pushing all the water through can have the piston impact the screen in a negative way and 3. personally I find it hard to believe that 'James Hoffman' doesn't have a scale that would fit. There's a bit of arrogance from Hoffman in that he thinks he has a 'better way' than the one Mr. Pratt uses.