Cafelat Robot day 1 issues - Help needed - Page 5

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mixespresso (original poster)

#41: Post by mixespresso (original poster) »

Hi all,

I recorded 2 vids today: preparation and extraction

The first one is about the coffee preparation
- Peruvian beans, roasted on Sept 20th
- The dose is 16g
- I ground quite fine. I tried to show it in the video, but I am not sure if that can be seen properly. In the Mignon grinder, the setting is more or less half a number above the burrs touching.

Here is the prep video: https://drive.google.com/file/d/1xmoRY5 ... IHu60/view

mixespresso (original poster)

#42: Post by mixespresso (original poster) »

This second video is the actual extraction. I wanted to show both the pressure gauge and the actual extraction flow , so I tried to do a multi-angle.
The water was off the boil and the PT was filled to almost the top

Here is the video of the extraction: https://drive.google.com/file/d/1Z011ff ... sp=sharing

- The gauge cannot be seen very clearly, but the pre-infusion happened at 1ish bar, and the extraction happens at 2ish bars.
- The grind was quite fine, so I'd have expected a need for higher pressure to pull that shot

Any insights would be great. I will record another vid tomorrow

thanks!

Jonk

#43: Post by Jonk »

So, puck resistance is dynamic. If you press hard, resistance goes up. It might feel unintuitive - but if the shot is too fast you can often slow it down by pressing harder. Try shooting for higher pressure and see what happens.

Other than the low pressure it looked pretty nice in my opinion. The tamp didn't look perfectly straight, and you can see that flow started earlier on one side (even started dripping before beading started on the opposite side). Practise tamping straight or get some kind of leveler (for example the official leveling tamper or a 3d print).. but it's not the main cause of your issues, just a minor detail.

Also, somewhere around 4 bars is where real 'espresso' starts in my opinion. You don't have to aim a lot higher, many go for ~6. But you should be able to hit 10 or more if you really want (my recommendation and I think Paul's is to stay below 8-9)

mixespresso (original poster)

#44: Post by mixespresso (original poster) replying to Jonk »

Thanks @Jonk, I will keep it mind

My feeling/worry is that if a press harder I will get a 5s shot, but I will try it. I am also thinking to go as fine as possible to chock the robot and see if can test the pressure vs weight with a scale

mixespresso (original poster)

#45: Post by mixespresso (original poster) »

Jonk wrote:The tamp didn't look perfectly straight, and you can see that flow started earlier on one side (even started dripping before beading started on the opposite side). Practise tamping straight or get some kind of leveler (for example the official leveling tamper or a 3d print)..
I might try this trick from the Wired Gourmet channel. He suggests a roll of scotch tape at t=221s: http://www.youtube.com/watch?v=4oWTr3wrIO4

mborkow
Supporter ♡

#46: Post by mborkow »

How did the shot taste and how was the mouth feel? If they were both good...I'd say ignore the manometer (I have the non-barista version so don't have one anyway).

jpender

#47: Post by jpender »

A 2bar shot is out of the range of traditional espresso. It didn't seem like you were straining so I still don't understand why you can't get to 5-6 bar.

That roll of tape hack: wouldn't it be a magnet for coffee dust? I would expect it to look pretty ugly after using it for a while.

Also, that guy didn't know what he was talking about with regard to heat, temperature, and the piston.

mixespresso (original poster)

#48: Post by mixespresso (original poster) replying to jpender »

re: tape hack
I was just thinking of using it as a temporary hack to ensure I am not adding any side-channeling. I agree it looks awful

The 2bar shot also does not feel right to me either. In that shot, I had very little resistance when I was pushing with my hands. So, as of today, I don't think I can have any control over pressure profiling which is one of the features of the Robot.
Maybe I have to push harder to have more resistance as suggested by @Jonk but, because of the low resistance I was facing, I was afraid of finishing the shot in 5s. I might use a bathroom scale to check the weight <> pressure ratio too

As a test to ensure my grinder is not (again) the issue, I prepared myself a shot with my humble DeLonghi machine using exactly the same grinder settings. The dose was 17g (vs 16g with the Robot), as 17g is the minimum dose with my naked PF. I recorded it in video and I had a very decent 1:2 shot in approx 30s. This, I think, confirms the grinder is OK

https://drive.google.com/file/d/1GPxWVF ... sp=sharing

Jonk

#49: Post by Jonk »

You should not expect to use the same grind size with the Robot as the Delonghi. If I'm not mistaken is has both a 51mm basket and excessively high pressure, requiring a relatively coarse grind.

The Robot has a wider basket, instant water delivery and can use pre-infusion - all things that requires finer grind. Finer than you'd normally use in most pump machines without pressure or flow profiling. So please: grind finer, preferably using fresh beans and enjoy the results.

mixespresso (original poster)

#50: Post by mixespresso (original poster) replying to Jonk »

Yes, I was not suggesting the grind should be the same. It was just a test to confirm the grinder is working OK

I will go finer tomorrow morning and see what happens. I have little experience but I do think the grind is already really fine (powder-like). I am not far from getting the burrs touching, but who knows this might be the way. let's try it