Hello, I got my Robot Barista since 3 days and I wanted to use it with my Bendinelli Armonioso (90% Arabica+10%Robusta) Espresso beans. Grinder is a Kinu M47. Before I used a Bialetti Brikka, the Espresso was grinded coarser so the crema valve gets activated. For the first attemps with the Robot I grinded the Armonioso with very fine grind, but now it tasted very bitter and sour. I adjusted the grinder a bit more coarser but now I got no pressure on the manometer of the Robot. There was litte resistance and the bitterness stayed. This morning I even grind coarser and tried to use the pressurised basket. The water runs through and again I can't obtain any pressure. But the taste would be ok...!! What can I do? do more tampering of the coffee?? before I tampered very light. the amount I use is 14g coffee, ratio 1:2
thank you

Suggest upping your dose for one thing -- perhaps 17g or 18g? -- and trying a different high quality grinder, in case your M47 is aligned such that your grounds are very uneven (you probably wouldn't notice that with a moka grind). Bitter usually means overextraction and sour underextraction, so unless your coffee likes unusually hot water temperatures -- or it's very stale -- you seem to be getting the worst of all worlds.

jfranco wrote: For more, check out: Does basket diameter matter?.

I'm more of an "I'll come to my own conclusions based on experiential data" than listen to the tales of dozens of others.

So far, having owned the Robot for about 1/10th as long as the Flair Pro using the same grinder (Kinu M47) and same coffee (Brazil Sul De Minas from my local roaster every week), the shots are better by magnitudes, not just marginally.

Diameter is interesting but I'm not really interested in diameter if the depth is not kept a constant. I'm more interested in the puck depth relative to the average amount of coffee one might use in a shot. You say diameter doesn't really affect it, then I'll cross it off my list of reasoning behind why the Robot is superior to the Flair Pro and keep looking.

GTO wrote:Hello, I got my Robot Barista since 3 days and I wanted to use it with my Bendinelli Armonioso (90% Arabica+10%Robusta) Espresso beans. Grinder is a Kinu M47. Before I used a Bialetti Brikka, the Espresso was grinded coarser so the crema valve gets activated. For the first attemps with the Robot I grinded the Armonioso with very fine grind, but now it tasted very bitter and sour. I adjusted the grinder a bit more coarser but now I got no pressure on the manometer of the Robot. There was litte resistance and the bitterness stayed. This morning I even grind coarser and tried to use the pressurised basket. The water runs through and again I can't obtain any pressure. But the taste would be ok...!! What can I do? do more tampering of the coffee?? before I tampered very light. the amount I use is 14g coffee, ratio 1:2
thank you

I use a Kinu M47 as well and got the Robot a few weeks ago. What setting from "zero" are you at on the Kinu? I'm at around 2.6 - 2.7 (full rotations.clicks) from my zero which is actually around the number 3 mark... so asking this is a bit pointless. This gives me 10 seconds of preinfusion followed by about 18 seconds of extraction at 8 bars and then 7-10 seconds of extraction at 6-7 bars for the best shots I've ever had.

I grind with the Kinu... Dump it in the PF. Shake the PF (while level) slightly to level the grounds followed by, as suggested by Paul, a finger tamp. I just let the tamper rest on the coffee bed using its own weight, then press down just until I start to apply my own force and feel resistance, give it a small spin and slowly pull it off to minimize suction. Then do everything as usual. I weight the amount of water I put in the PF though. I use 16g beans and 56-60g of water which usually gives me about 32-35g out.

So do you have both baskets, the professional and the pressurized? You said you had a Kinu and mentioned adjusting your grind size so you obviously grind your own coffee but then mentioned using the pressurized basket?

GTO wrote:...The water runs through and again I can't obtain any pressure. But the taste would be ok...!! What can I do? do more tampering of the coffee?? before I tampered very light. the amount I use is 14g coffee, ratio 1:2
thank you

Definitely don't want the water to run through - would be far from optimal extraction. I use 17 - 17.5 grams of coffee with Kinu M47 (very recent model) set to between 2-0 and 2-1 (2 full counter-clockwise rotations + a tiny bit). Have noticed some small difference between two different espresso beans - one type required more time to get preinfusion drops to trickle and to push water through so I'm increasing the size of the grind slightly for that one.

I use a Kinu M47 as well and got the Robot a few weeks ago. What setting from "zero" are you at on the Kinu? I'm at around 2.6 - 2.7 (full rotations.clicks) from my zero which is actually around the number 3 mark... so asking this is a bit pointless. This gives me 10 seconds of preinfusion followed by about 18 seconds of extraction at 8 bars and then 7-10 seconds of extraction at 6-7 bars for the best shots I've ever had.

Hello, thank you for your answer... my M47 is like yours and now my settings are at 2.9, 16g of beans
My cappuccino now tasted without bitterness, a little bit too weak (next time I will grind with your settings) but it remembers me
about my italian holidays at the Lake of Garda, drinking cappuccino at the harbour of Lazise... haha that is the aim !!!
but to the reality: still I got no pressure, now tampered better, perhaps with a little finer grind

GTO wrote:...still I got no pressure, now tampered better, perhaps with a little finer grind

Try finer + maybe 16.5 or 17g of beans, until coffee starts going bitter. Decent tamper pressure but no need to put 80kg on it .

mlunsford27 wrote:Has anyone experimented with some different preinfusion techniques? I have been using a very slow (~30-40 s preinfusion) which has produced some good pours and incredibly smooth and creamy shots with an Ethiopian roast from Stumptown.

I was wondering if anyone has a tried a bloom similar to what Scott Rao describes when using a DE1+? I tried something of the sort, 10s preinfusion til I see drops then stop preinfusion for 30 s to allow to bloom, with mixed results. Has anyone else given it a try with lighter roasts or medium-light roasts.

I got some numbers this AM--all temps in F. Ambient temperature was 63. I took the temperatures with the PF sitting on the rubber mat-not mounted. I only ran two trials--cold and pre-heated. At pour the temperature for both was around 205. At 30 seconds the cold was 172F at 40 it was 169. Pre-heat temp at 30 was 191 at 40 it was 187. The pre-heat at 20 seconds was 194? (smudged sorry)

I don't like these temperatures, at 40 seconds with lighter roasts. YMMV

Where/how did you actually take those measurements? With some probe mounted somewhere/kitchen thermometer / during the pull/simulating the pull by having a hot water in the basket ?

Not mounted with a ThermaPen. In one of Mr. Pratt's videos he does some measurements with a thermocouple. He dents the screen, so. . . .I did not simulate pulls.

Yeah, I thought so. It's just an approximation, conditions during real pull are different so is the speed of cooling. But anyway, it's obvious that these machines without a heat source cool down during the pull ...