Cafelat Robot low doses

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Paul_Pratt

#1: Post by Paul_Pratt »

In another thread this was posted by renatoa saying that a low dose in the Robot is not possible.

I am not here to advertise or push anything but there is a lesson here in that it is important to keep an open mind about things until you have tried them for yourself. I will not pretend that the Robot basket is anything other than a commercial size 58mm double basket. To say otherwise would be untrue. However I do say that people can experiment, start with 16g and go up or down from there. How low can you go will depend on your bean, the grind setting and of course the particular taper of your own basket.

When I developed this basket I tested down to 10g and up to 22g. They are extreme numbers but can be done. Anyway to the point of this post, it was mentioned in the other thread that it would be impossible to extract at 6 bars with the Robot basket and a lower dose which I know not to be the case. So just now I made a very quick video showing a 10g dose, grind setting the same as I used on my faema lever which is next to it. I am sure if I spent the morning dialling it in I could make it look social media pretty but I do not have the time for that. This is the 2nd shot I tried. I do not usually go for 8-9 bar extraction pressure but wanted to just demo it for the video.
Yesterday I wrote a comment on the video espressotime posted of his Lambro. I mentioned that I believe the pre-infusion stage is everything on a lever machine. It controls the volume of the shot, the bite of the lever as well as regular benefits of pre infusion. Anyway I am also a big believer of tapered baskets on lever machines. The straight walled baskets (and especially high flow fancy baskets) do not do the machines or the coffee justice. They are just easier to work with and give great results. So for that reason I have my basket designed as below



The basket is not straight sided at all. I am not saying it is better than XYZ or whatever. I am sure the sweet spot is in the middle range that I recommend people start out with. But it certainly can extract at low doses and high extraction pressure if you want to (and are able to get your tamper down far enough).
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mborkow
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#2: Post by mborkow »

I have pulled delicious (to me and mine anyway) shots on my Robot with as little as 10g to as much as 14g (at 2:1 ratio for me and 3:1 for the rest of household). I've currently settled at 13g for freshly roasted coffee and add in another .5g as the coffee ages over the back half of the week as I drink it. I can't tell you the exact bar but I've been using levers (vintage Creminas and Europiccolas) for near 20 years and even at 10g I got what felt like was good pressure and preinfusion. I'd love a "single" Robot basket to go down to 8g but I've settled on the one larger (13g dose) espresso each AM rather than the two 8g dose espressos I used to make with the vintage levers (caffeine seems to affect me more as I get older anyway so that reduction in total coffee consumption isn't really a bad thing but every now and then when I need a little more I make a second).

mborkow
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#3: Post by mborkow »

13g dose

DonFelipe

#4: Post by DonFelipe »

Thanks for the post.
Paul_Pratt wrote:... believer of tapered baskets on lever machines...
Whats a tapered basket is?

Marcelnl
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#5: Post by Marcelnl »

DonFelipe wrote:Thanks for the post.



Whats a tapered basket is?
The basket is getting smaller in diameter towards the bottom, sort of like a cone does in a kindof V shape.

My experience too is that 14 g works just fine with the Robot, it's my usual dose for the Urania, but while away on vacation I do not measure and use 'a spoonfull' as measure and have never had the Robot fail to produce espresso ...which always amazes me given how haphazardly I make espresso on vacation.
LMWDP #483

pham

#6: Post by pham »

Hey Paul and others here, there are honestly a lot of fascinating points being made here and I'd love to get some elaboration on a few points if at all possible:

1. Low doses: In my experience I think it's perfectly possible to pull low doses on a 58mm basket, especially since it's a direct lever. Given that the grind required will be quite fine, if one wants to pull a higher pressure shot then you'd compensate with a shorter preinfusion and a faster ramp to pressure as Paul has done in video. If you preinfuse, I would expect that you can still pull a high pressure peak shot and the pressure would degrade quite quickly unless you are pulling a shot that accelerates quite quickly. That's my normal SOP, but I generally still prefer the taste of larger doses. But to say "impossible" is a dangerous term as Paul noted.


2.
The straight walled baskets (and especially high flow fancy baskets) do not do the machines or the coffee justice. They are just easier to work with and give great results.
I'd love to dig into why this is and what characteristics we're looking for in these statements. My guess is that, on a direct lever it is intuitive for the user to preinfuse gently and have a smooth, gentle ramp to peak pressure, and in my experience that has resulted in needing quite a fine grind. I'm putting it out there that the taper on the Robot is there in order to compensate for that and make the grind setting used roughly equivalent to pump machine that uses a straight walled 58mm basket. My friends that own a Flair 58 and high-flow baskets tend to grind quite a bit finer than I am on the Robot or a pump machine. (sidenote: a friend of mine has replicated that finer grind size and flow rate on their e61 via using a needle valve to restrict the gentler ramp rate after a quick preinfusion, which is why I have this suspicion).

3.
Yesterday I wrote a comment on the video espressotime posted of his Lambro. I mentioned that I believe the pre-infusion stage is everything on a lever machine. It controls the volume of the shot, the bite of the lever as well as regular benefits of pre infusion.
Does the "bite point" influence the peak pressure at the puck on a commercial style spring lever? My spring lever experience is limited to a Faemina, which due to its filling characteristics will always bite at the same point and give the same pressure profile unless the ramp is changed. There is that video that Frans posted on the Londinium R where varying the preinfusion pressure in the HX influences the bite point quite dramatically.

beardsicles

#7: Post by beardsicles »

My standard dose has been 14g for a while.. never had any trouble whatsoever. 10 second pre-infuision. But I also grind very finely and use both the metal filter screen and a paper filter.

Rabh

#8: Post by Rabh »

I've never gone as low as 10g, but I'm loving the shots out of my Robot at 12.5g to 13g. I go for about 10 seconds of pre-infusion (on medium roasts), and a 30 to 35 second pour at 1:2 (so 26g of espresso out), and that gives the perfect balance of sweetness, for my palate of course.

At higher doses I find I have to grind coarser, and gives me more sourness/acidity then I like. Of course I'm sure there are plenty of people who like that, it's just a bit much for my tastes.

All this is with a conical grinder (Helor 106). I'd love to try it out with a flat to see the difference.

jpender

#9: Post by jpender »

Rabh wrote:At higher doses I find I have to grind coarser, and gives me more sourness/acidity then I like. Of course I'm sure there are plenty of people who like that, it's just a bit much for my tastes.
In a way you're saying the opposite of what prompted this thread. If your espresso is sour with higher doses you probably just need to grind finer or pull longer. I'm not saying it will taste identical but there's no reason why you couldn't get a balanced, well-extracted coffee from a 16-20g dose. It isn't that people like sour or even acidic coffee. It's that they've learned to pull at the dose they prefer.

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yakster
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#10: Post by yakster »

Pulling a larger dose at a higher temperature including possibly pre-heating should also help if your getting sour shots when you increase the dose.
-Chris

LMWDP # 272