Cafelat Robot User Experience - Page 52

December 16th, 2018, 3:17 am

Back to trying to dial in that coffee on a Robot, I would preheat the basket and portafilter as much as conveniently possible, then try a fine grind, downdosed, a sufficient gentle preinfusion, high pressure to start, tailing off pressure to avoid overextraction, and ending the shot toward the light range of color, meaning it's been more extracted and is milder.

References here:

Better Extraction, Better Espresso - Espresso Guide

Diagnosing Espresso Extraction Problems - Espresso Guide

December 16th, 2018, 9:45 am

drgary wrote:If you superheat in a microwave the water can flash boil out of its vessel. I would be careful with that. There's a trick to reducing that risk but wouldn't it be easier to go for a darker roast or use a closed-boiler machine, especially a 2nd gen La Pavoni that easily overheats at sea level?

Added: Here's a link to a thorough explanation of the dangers of superheating water in a microwave. From that page:

"If one litre of water is superheated by only 1 °C (i.e. if it is heated to 101 °C without boiling at normal pressure), it is in an unstable state, and it can suddenly produce about 3 litres of steam. The rapid production of a substantial quantity of steam within the bulk of the water will cause it to boil vigorously and possibly to appear to explode. The result is boiling water flying at speed out of the container."

For the rest, which is a very good read:

"Superheating and microwave ovens." UNSW School of Physics, Sydney Australia

This, do not try and heat water in a microwave to anywhere near boiling range it has bad news written all over it!

#513: Post by **sosha** » December 16th, 2018, 11:35 am

So, I've just joined the Robot Club. Merry Xmas to me.

I've found this machine to be VERY forgiving and simple. I had dinner company last night, and decided to bring it out, eventho I had pre-heated the E61 machine in anticipation. Was using Redbird 7 days post roast, and the results were stunning. Very happy I got the Barista version, because the PG has been interesting. I'm sure, with practice, I won't be noticing it as much.

I just wish I had purchased additional baskets and screens, as it would speed up the process of pulling multiple shots.

#514: Post by **yakster** » December 16th, 2018, 2:31 pm

I find it's a good idea to flush the pressurized basket after use with a pull of clean, hot water.

Eventually maybe portafilter cleaner.

#515: Post by **IMAWriter** » December 16th, 2018, 4:33 pm

drgary wrote:I'm using 21 gm as my max and haven't run into problems doing so. It depends on the coffee, the grind, etc.

Wow. I guess I refrain from that large a dose due to the fact I can get a bit dizzy pulling that much coffee. I think that's why I NORMALLY preferred a 49mm Group.
You've forced me to give it a try with a SO Panama Elida DP...if only to see how the filter sits atop that mountain of grind.

#516: Post by **IMAWriter** » December 16th, 2018, 4:57 pm

Well,
I went with 21 grams in, 41.5 grams out...but I went with 7 day old Klatch Belle Espresso. I tasted no significant difference as my same ratio I use normally...17 grams in, 34 grams out.
What I DID notice was an inability to lock the portafilter in. I had to use the tamper to depress the filter (while the basket was filled with water!) to allow the PF to slide in. I also had that wee bit of "buzz" that accompanies a triple shot...really almost a triple restretto.
What is even more interesting is that even with all the delay, manipulation, etc, the shot poured perfectly, and tasted VERY good. Unless I'm going with a lighter roast, I'll stick with my 17 grams (give or take depending on the bean.) Different strokes!!

December 16th, 2018, 7:29 pm

I did a 21 gm dose this morning of a home roast I'd baked. So I ground coarse and pulled a shot that emphasized the sweetness and chocolates that were still there. It worked well with no difficulty getting the shower screen in place. Portafilter lock-in was the same as usual. No difficulties.

#518: Post by **yakster** » December 16th, 2018, 8:31 pm

I'm only dosing that high when I'm splitting shots to shave time on morning drinks for my family

December 16th, 2018, 9:14 pm

It's not my usual but am underextracting on that coffee.

#520: Post by **vinodism** » December 17th, 2018, 12:49 am

drgary wrote:If you superheat in a microwave the water can flash boil out of its vessel. I would be careful with that. There's a trick to reducing that risk but wouldn't it be easier to go for a darker roast or use a closed-boiler machine, especially a 2nd gen La Pavoni that easily overheats at sea level?

Added: Here's a link to a thorough explanation of the dangers of superheating water in a microwave. From that page:

"If one litre of water is superheated by only 1 °C (i.e. if it is heated to 101 °C without boiling at normal pressure), it is in an unstable state, and it can suddenly produce about 3 litres of steam. The rapid production of a substantial quantity of steam within the bulk of the water will cause it to boil vigorously and possibly to appear to explode. The result is boiling water flying at speed out of the container."

For the rest, which is a very good read:

"Superheating and microwave ovens." UNSW School of Physics, Sydney Australia

Glad I read it before trying it , yeah its a risky thing , I wont do that