Cafelat Robot User Experience - Page 3

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vit

Postby vit » Oct 05, 2018, 4:17 pm

drgary wrote:That's why we write reviews.


Gary, what is the weight of the basket alone? It should be considerably lighter compared to mass of Flair cylinder and metal part of the basket, that would explain good results of your initial tests

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drgary
Team HB

Postby drgary » Oct 05, 2018, 4:21 pm

Nate42 wrote:Gary, so you are suggesting add coffee, tamp, add shower screen, then pour in and discard preheat water? And this doesn't disturb the coffee under the screen?


Not enough to matter. Sam will write more about this in the review.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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drgary
Team HB

Postby drgary » Oct 05, 2018, 4:27 pm

vit wrote:Gary, what is the weight of the basket alone? It should be considerably lighter compared to mass of Flair cylinder and metal part of the basket, that would explain good results of your initial tests


No time to measure at the moment. The basket is hefty because it includes the cylinder. Heating as described it worked.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

samuellaw178
Team HB

Postby samuellaw178 » Oct 05, 2018, 4:42 pm

TLDR: Based on my measurements, I believe the Robot does work.

This is preliminary observation so take it with a grain of salt - though this is the second time I am measuring the temperature using similar procedure and they are consistent. Will repeat the measurement for the final review article.

The Robot basket (and cylinder in-one) weighs about 83g. For reference, the VST basket I have weighs about 34g.

To measure water temp, I pour off-boiled water (PID Bonavita kettle set to 100 deg C) into the basket (with 18g of tamped coffee and shower screen in position) and immerse a thermocouple in the water above the coffee puck.

Without any preheat and a room temperature of 20 deg Celsius, I obtained a temperature of 90-91 deg C about 5-10 seconds in.

Using the preheat method Gary mentioned above (suggested by me :D ), the temperature is easily bumped to 93-94 deg Celsius. Considering the fact that the probe is measuring the water directly in contact with coffee puck (which absorbs heat) and it is probably losing heat as the measurement process is going on, the number seems pretty good.

Compared to SCACE (typically aims for 93 deg C/200 F, but requires the plastic puck to be preheated prior to measurement) or Decent Espresso machines (that routinely pulls at temperature of 90 deg C by measuring temperature directly above puck), the Cafelat Robot seems to have a very good baseline to work from.

By doing the discard-preheat, you do lose some lightly-brown water. However, I tried to measure the TDS lost using Atago refractometer, it seems negligible - not measurable and likely represents less than <<<0.1% extraction yield loss based on calculation. So although the procedure is rather unconventional, it seems like there is nothing to worry about.

For second shot onward if you are pulling back-to-back shot, I don't think there is a need for more preheating. The basket/pf only requires a slight bump in temperature so that the final brew temp is in the correct range (assuming you are not at 1000m above sea level :lol: ).
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instantkamera

Postby instantkamera » Oct 05, 2018, 9:31 pm

Nate42 wrote:Gary, so you are suggesting add coffee, tamp, add shower screen, then pour in and discard preheat water? And this doesn't disturb the coffee under the screen?


I swear Sam had a video of him doing this with the baby faemina on YouTube, but now I can't find it. It seemed to work fine, but am I dreaming up things? :?:

samuellaw178
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Postby samuellaw178 » Oct 05, 2018, 9:47 pm

instantkamera wrote:I swear Sam had a video of him doing this with the baby faemina on YouTube, but now I can't find it. It seemed to work fine, but am I dreaming up things?


Not at all - you weren't imagining things. You mean this embarrassing video right (it was unlisted so you probably couldn't find it)?? :oops: The preheat method happened around 1:40.

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Balthazar_B

Postby Balthazar_B » Oct 06, 2018, 8:56 am

Sam or Gary, just curious. Are the portafilter/basket components ferromagnetic, by any chance? You can guess why I ask...
- John

LMWDP # 577

Javier

Postby Javier » Oct 06, 2018, 9:28 am

samuellaw178 wrote:To measure water temp, I pour off-boiled water (PID Bonavita kettle set to 100 deg C) into the basket (with 18g of tamped coffee and shower screen in position) and immerse a thermocouple in the water above the coffee puck.


Hey Sam! Curious question. For a given dose, do you need to add a predetermined volume of water in order to obtain a desired mass of espresso? For example, for a 14 grams dose, if aiming for a 1:2 ratio (and therefore 28 grams in the cup), do you need to add, e.g., 40 grams of water to the basket? The manual seems to indicate not to leave too much headspace on top of prepared basket.
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Balthazar_B

Postby Balthazar_B » Oct 06, 2018, 10:11 am

Javier, in one of Paul's videos on the Kickstarter pages, IIRC he demonstrated how to stop a shot pull before all the water in the column had been used. This implies that -- as is that case with spring levers -- that while the volume of water in the grouphead will be more or less constant, regardless of puck volume (between 10-21g of coffee), one just extracts to the concentration one prefers in all cases. With a spring lever that means pulling the cup somewhere along the way. So FWIW my hypothesis is that best practice will be to always fill the portafilter to the same constant level and go from there.

Maybe this will be one of the tips/tricks that Sam or Gary posts shortly? I'm curious as to the upper limit of how much water can be accommodated with a 21g dose of coffee. Will a lungo require starting from a smaller-than-a-21g dose of ground coffee?
- John

LMWDP # 577

schneckerl

Postby schneckerl » Oct 06, 2018, 11:44 am

I guess it's always preferable to fill it up to the max and to stop the pull according to preferences. More water = higher temperature.

Hence the question of whether there's a marking line in the basket, like in the Flair. Which would also help with comparability. Would also allow avoiding spillage or damage to shower screen.