After traveling 7,800 miles in 2 days my Robot has arrived!

I added the Robot hands, but was not expecting for them to already be installed. Thank you Paul for that!
GRINDER: OE Lido 2 w/ Italmill burrs
BEANS: Lavazza Espresso Barista Gran Crema (fresh is best I know, but I'm learning)

First attempt:
18g at 1:2 in 15 seconds after pre-infusion
Was the best sour shot of coffee concentrate I've ever had... lol

Second attempt:
18g at 1:2 (finer grind) 28 seconds holding steady 6-7 bar and tapering at the end.
This was so much better. I'm looking forward to the next one.

Seems as though I'm grinding to fine.

Jonk wrote:Sure - but speaking from my own experience - to reach 9 or even 6 bar on a Robot, Europiccola and MiniGaggia a finer grind is more or less required. Made obvious by using the same dose and basket on a MiniGaggia and regular pump machine.

Of course, in the case or the Robot there's plenty of space to updose if a finer grind is not possible for some reason.

Apologies in advance as I have not read back to get the context of your point. My own experience is that a smaller basket diameter requires a finer grind than a 58mm. For example in my office this year I have generally used 4 machines on my monolith flat. The Robot and my large lever machine (using the modern lever group) has the exact same grind setting. My 55mm LSM lever has a finer grind and my La Pavoni 49mm has a finer grind than the LSM.

However that is probably not what is the case here. What I think is happening is something that Gary mentioned, puck resistance. With a manual lever with a gauge you are getting the pressure reading directly from where all the action is - right at the puck. If the grind setting is too coarse the water will flow through the coffee, you will not be able to build up resistance and you will struggle to get a high pressure reading. This is the number 1 email "complaint" we get when people unbox their machine with the gauge. Only after they adjust the grind finer will they create puck resistance and see the gauge needle move.

On a rotary pump machine there are a few things at play. The first is that there is a gicleur or flow restrictor that does exactly what it says, restricts the flow through a 0.8-0.6mm hole. The second is that the pressure gauge reading is taken after the pump and before the flow restrictor, therefore it does not matter what grind setting you have you will see the gauge needle go up to the magic 9 bar or whatever you it set at. If you were to compare the manual lever and a pump in this manner of course the conclusion drawn would be the pump machine can hit 9 bars easy, and manual levers are just more fussy - but in reality the comparison is flawed because of the flow restrictor. If you take a Scace2 device to the group and measure extraction pressure you will see the group reading is slightly lower than the pressure gauge on the machine.

On some vibe pump machines (e.g. Sunbeam or the Brevilles IIRC) the pressure gauge is like a manual lever, no puck resistance means a low pressure reading on the gauge and you need to adjust the grind accordingly. My memory is fuzzy but I think it was the Sunbeams that had something written on the gauge dial that told you to grind finer or coarser.

So what does all this mean? Well mainly since the pressure gauge readings are taken at different points comparisons will be hard. Let us pull a 5 second shot on both types of machines. A pump machine will always tell you you are spot on 9 bar when in reality the pressure inside the basket was not even close to 9. If on a manual lever machine you are pulling 5 second shots I can tell you the needle on the gauge would not even move one bit. In both cases you would need to adjust the grind much finer - on the pump machine you would think you are just fine tuning because hey I'm at 9 bar anyway. On the manual machine you would assume you need a major rethink of the process because I am getting a 5 second shot AND no pressure whatsover. So it is quite misleading but an important point to note.

If anyone here has the Robot pressurised basket you can fill it with water, cold will do, and pull a shot. Because of the flow restriction you can easily get 9 bar, I bet you could max out the gauge - I test each Robot to over 14 bars. This is possible because of the flow restriction, and of course your effort on the levers. That is why the pressurised baskets work so well with pre ground stale coffee. The coffee may be offering hardly any resistance at all, but it does not matter because of the tiny outlet hole in the basket which backs up the flow and allows you to create pressure.

Of course there are other factors such as dose and how hard you press or pull the levers, but the puck resistance is the key - no resistance and you cannot build up pressure. The other main factor is that pump machines take the pressure reading before the gicleur and will tell you, you are at the 9 bar number all day long whether you are doing 5 second shots or 30 second shots.

When placing a new order for a Robot, what other recommended accessories or maintenance items should I purchase? For example, extra silicone seals , baskets, etc. Thank you.

Brewzologist wrote:When placing a new order for a Robot, what other recommended accessories should I purchase?

I'd suggest a few cravats in raw silk; keep it louche.

Brewzologist wrote:When placing a new order for a Robot, what other recommended accessories or maintenance items should I purchase? For example, extra silicone seals , baskets, etc. Thank you.

Opinions will likely differ, but if it were me I'd buy the Robot Hands, a Filter Screen, and 3 seals.

Jonk wrote:Part could be because of pre-infusion

To me, pre-infusion is probably the most important factor in why people get gushers with the robot or feel the need to grind super fine if they're coming from normal pump machines.

The instructions on the robot tell you to wait until you see the bottom fully bead up. That's like what you hear on spring levers about holding the lever down until you get drops from the bottom. If you're coming from nearly any pump machine, then, you're used to a machine that delivers full pressure before the puck is fully saturated. That makes an absolutely enormous difference on how fast a shot goes and how much crema you get in a shot.

I've been visiting family who have a breville barista express ( I have my own kinu m47 traveler with me) which gives you full manual control over preinfusion duration and shot duration. I dial the kinu in for shots that build pre-infusion to about 3bar on the puck-pressure gauge, give some drops, and then take about 25-30 seconds for a 2:1 ratio at full pressure. If I just let the pre-infusion build to only 2bar at the same grind and start full pressure (so, some pre-infusion but not full puck saturation), i'll be lucky to get 10-15grams of liquid out after 30seconds. And if I let the only 'pre-infusion' be the natural time it takes the vibe pump to build pressure (the barista express is quite slow to build pressure normally), it'll choke it every time.

I've done the same thing, albeit less precisely, with my Lelit Elizabeth at home where I can vary the pre-infusion length and it requires signiicant adjustments in grind. A grind level that chokes a machine with only a few seconds of preinfusion creates a gusher on a shot with 8-10seconds of pre-infusion. Crema shows the same effect. If you want more crema, don't wait for full preinfusion. For me, the change in grind setting related to pre-infusion is on a par with the changes required for going between light and dark roasted beans.

And, I've found the same with the robot. Reducing pre-infusion generates more crema and requires a coarser grind.

So, for folks coming to the Robot from standard pump machines, or taking grind setting recommendations from people with more standard pump machines, or finding themselves unable to avoid gushers, just reduce the pre-infusion.

hercdeisel wrote:Reducing pre-infusion generates more crema and requires a coarser grind.

Are you certain that the increase in crema is a result of less pre-infusion? Or is it due to the necessarily coarser grind?

A fair point, I haven't been able to test the independence because the only way to get a reasonable shot with the coarser grind is to reduce pre-infusion.