woensdag 29 juli 2015

Amsterdam Coffee: Bike to Cup

Moyee Coffee, a "fair chain" coffee trader in Amsterdam sent me an email about a new service they provide for people who urgently need a fresh pack of beans roasted in Africa. They arrange free delivery by bicycle anywhere in Amsterdam.

I like it how their concept of an international enterprise also has a very local focus. Moyee is working to reward local African farmers who are enabled to ship their beans roasted and ready and now their supply chain is adding a delivery service on the other extreme end, to the front door of their customers.

Moyee is a very young and hip enterprise and it shows in the closing words of their mailing: "Veel liefs" -- in English that would be something like "Sweet love".

It communicates to me that I might be way too old for them. "Sweet love" is something that 17 year old girls write to each other in whatever social media app is currently "in". It's also used by 40 year old Uggs women who dress in tight stone washed ripped jeans like 17 year olds but I do not fit into that category either. 

If I would close an email to a business partner with "Sweet love" I would probably be ignored really fast and if I sent something like that to a young female acquaintance I could get in serious trouble. 

Still I was interested in the idea and I downloaded the TringTring app for local food delivery by bicycle couriers:

It promises some wonderful alternatives to have precious fresh food delivered to the home or office. The good life brought to you in the most sustainable way possible, by bicycle.

I have never visited the White Label Coffee shop even though they just a few blocks from my home. I heard they know their business and two of their baristas even won championships in Aeropress. So this was a fine opportunity to have some of their beans zipped over to me.

Registering the app was easy, the PayPal option is not yet ready but the Credit Card option was quite nifty: take a picture of your card, enter the expiry date and security code, done. 

I selected some Rwandan beans, Bourbon type, grown at 2100-2300m altitude which White Label have roasted themselves after buying from ThisSideUp coffee traders.

A little later I received a text message announcing the delivery. The guy handed me a bag with receipts, checked a code from my text message to make sure the right person had received the order (very clever detail) and left for his next delivery:

Thijs from TringTring waving goodbye
Below are a few pictures. The beans are roasted very light as is the fashion these days, so it's best  to go along and also updose as is done by many baristas today. I also want to try to mix/blend these fruity beans with Brazil Mogliana beans that I recently roasted.

The shot below was made using a 17g dose in the 15g VST basket, extracting 33g of espresso in 29 seconds, so I could grind a little finer yet.

Bag as delivered, receipts attached

Using the Acaia Lunar scale to weigh beans for a 15.06g single dose grind on the Compak R120 grinder

zondag 26 juli 2015

"Zero" tracking on the Acaia scale for coffee

[More photos and videos about the acaia lunar here]

Mr Rex Tseng from Acaia explained some details to me about the "zero tracking" mechanism in their scales.

Initially I had no idea what this was about. One assumes that a scale shows the weight, period. For coffee, one ideally wants a scale with 0.1g precision so the optional 0.01g resolution of the Lunar is especially pleasant.

If there is no weight on the scale and it displays 0.00g then a number of circumstances can give the scale the impression there's some minute weight on or off it. At this rate of sensitivity, even blowing your nose near to the scale can make the scale sense the air movement and translate this into a temporary "weight".

But even though one wants the scale to ignore such tiny differences at 0.00g it is still necessary to display all minute changes when one is actually weighing off something. For instance, when measuring off an exact 14.00g of dose into a filter basket, one does want to see the numbers reflect the tiniest pinch of extra grinds added or taken off the dose.

The video above shows my checking this out and below is a quote from the message by Rex Tseng:

The tracking option in the settings menu is a technology for acaia scales to remain stable at zero. 

Here are some backgrounds of the weighing definitions:

min = minimum starting weight
d = minimum increment of the scale
max = maximum weighing capacity
e = margin of error

for the acaia Pearl (1.74)
min = 0.3g
d = 0.1g
max = 2000g

For all the scales / balances, the weighing result will drift over time due to many different reasons. The ‘zero’ point (0.0g) will drift, especially over a span of time. It could be heating from the electronics, can be the ambient noise, can be the room temperature changes, or simply because of a cheap / poor load cell sensor.

The zero tracking mechanism in acaia is designed so that it will track the zero point within certain criteria to allow the zero point to remain stable over the time span. For example, 

When the zero tracking range is set at 2d (2*0.1g = 0.2g) in the option menu:

If the zero point drifts from 0.0g to 0.1g (it can be a drift or putting a weight of 0.1g on the Pearl), it will be ‘tracked’ and the scale will read 0.0g. 

If the zero point drifts from 0.0g to 0.3g (it can be a weight of 0.3g on the Pearl), it will not be tracked and deemed as an object on the Pearl. 

This zero tracking allow the Pearl to perform long time consistency for the starting zero point. 

The zero tracking mechanism will NOT operate if there is any weight on top of it, it only operates around 0.0g. So if you put a 10g weight on the Pearl, and add 0.2g on the Pearl, it will show 10.2g. 

If you try with other low-end scale in the market, you will notice that if you turn on the scale for period of time without weighing, it will read from 0.0g to any numbers like +- 0.5. That’s also one reason low-end scales need to have an auto off set at 1 minute, in order not to show its unstableness. Another reason for low-end scale to set the min = 2g  (even though d=0.1g), is also because they were not able track the zero point, so they will ignore anything below 2g at zero point. 

So if you want to see the most responsive weighing result, you can make the zero tracking to 1d or OFF, the trade off will be a less stable zero point.

woensdag 22 juli 2015

Acaia 'Lunar' Scale for Coffee

[A separate blog entry about "zero tracking" on the Acaia is here]

Acaias Pearl and Lunar next to each other 

A first glance at my new scale. I knew from pictures on the web that it was going to be a smaller sized scale but this one is really small! Packed with features all the same, so I have lots to explore now.

I stacked both Acacias to check their LCD performance under bright lights and the black one does much better there. In the video, timing and weighing a shot of espresso on the LONDINIUM 1-P machine, it's striking how small the new black scale is in comparison to the white "mother ship".

Next I want to demonstrate the nifty feature of the new Acaia Lunar where it automatically sets the weight to zero after placing a cup on the scale and then it not only automatically starts counting time & weight when the first drops begin to fall, it also automatically stops time (and remembers the last stable weight) when the cup is lifted (on a lever machine for instance) or when the flow has stopped (like on an E61).

The latter was an early suggestion made last year October by Trevor Watters of Sydney so he will be especially happy to see this implemented:

zondag 12 juli 2015

Trying out a fluid bed coffee roaster concept

Tije is trying out some concepts for a fluid bed coffee roaster. A variac is regulating the power for the blower and in the pipe between blower and beans there's a heating element out of a paint stripper. In this setup, the blower seems powerful enough but the heater isn't. We might need to scale down the container holding the beans and aim for 500-600g of beans to roast in this way. We might also order another blower, one with less air speed but more 'static pressure'. And less noise ;-)

zaterdag 11 juli 2015

Tije's La Pavoni funnel

Tije made a nice little funnel for the pre-millennium La Pavoni lever machine. It has a thin sharp lip that exactly fits the filter basket so during the stirring of the ground coffee beans, I expect no fine grinds will be able to sneak into any crease.

Tije also made the tamper, using a piece of wood he took off his old sailing boat.

NAKED portafilter by http://www.naked-portafilter.com

maandag 6 juli 2015

Espresso on vacation

We went to stay in a little house in the woods near Oostvoorne for a few days so I had to leave my Londinium L1-P espresso machine and the huge Compak R120 grinder behind.

Luckily I have a small set of the bare essentials to treat us to some excellent espresso even here. It takes some tweaking, recalling how I did it last time, getting the HG One dialed in for a fine extraction but then, with the right beans and some luck, it's a near perfect run of most delicious coffee.

The Acaia Pearl scale helps to weigh off the beans and to time the shot. In the video below, I got a 25g espresso in 33 seconds using 14g (plus one bean) of grinds, with about 10 seconds pre-infusion.

I did most of the preparations single handedly because I was holding the iPhone camera with my left hand. Only when I did the stirring and tamping I needed both hands and I asked for assistance.

The external PID here is monitoring the group temp. When the group temp hits 85ºC I switch on the PID program which ensures the temp stays there. In this video, the temp was not there yet so I just let the La Pavoni's own pressostat do the work.

vrijdag 26 juni 2015

KdW Speedster with "Lever Style" hand pump pressure

A year ago I wrote a blog about Jip van Neerven, who was working on a modification of a Kees van der Westen Speedster espresso machine for his graduation project.
Jip van Neerven and modified Speedster
Today, having graduated, he presented the machine with his beautiful modification during the big exhibition of all graduated of his year.

Detail of pressure chamber device

Switches to open/close the pressure valves
The magnificent Speedster is already a fairly silent machine in the standard version with a rotation pump, but now the pressure needed to extract coffee is generated by a simple bicycle pump and no motorized part is active at all, much like in a lever espresso machine.

Pressure setting slider

Jip van Neerven explaining his work
The Jip-Speedster emulates a lever in more ways than just the pure "silent mode". It also mimics much of the beautiful pressure profile that makes many people love espresso from lever machines.

The bicycle pump is actually used to pressurize two chambers in the tall and slender steel column that's towering over the Speedster. Target pressure is about 10 bar.

The reason for having two chambers, one big, one smaller, instead of just one pressure source: once a the valve of a chamber is opened and the pressure used to push water of 92.5ºC through the coffee puck, the pressure drops somewhat in the big chamber (say from 10 to 9 bar). If one opens the valve of the smaller chamber, this pressure drop is much more significant.

Bicycle pump pressure gauge
This helps to get an extraction resembling a lever machine profile: pre-infusion at line pressure, extraction starting at 9 bar, slowly dropping and then, switching to the second chamber, a pressure further declining towards the end of the espresso shot.
Pressure gauges on the chamber column
Jip invited me to do some more testing soon. Today, he only had a very dark roast on the grinder with beans that glistened from coffee oils, so any subtleties in potential taste would remain hidden. We will next test with some different beans!

Some of the heavy Jip van Neerven coffee tampers

In the video, Jip explains how he has mainly focused on the technical aspects, wiring, hydraulics, and has yet to learn about coffee, so he is definitely not posing as a coffee connoisseur and he is not all all pretentious about such things. He enjoys learning and told me he looks forward to my comments later on when we can work together.

I think it's a brilliant test bench of hardware and I applaud Kees van der Westen for making all that hardware available for this project. He is not at all afraid that people will damage his brand image and I think that's a very generous standpoint.

Kees is abandoning his Idro lever production and I like it that there are others, even with his full and loyal support, to acknowledge the beauty of lever extractions, who like to experiment to emulate this.

Jip, meanwhile, is also developing a much smaller machine, La Pavoni size, with such pressure profiling.

The Netherlands is breeding espresso innovators, like Jip van Neerven and Wouter Strietman of the ES3, who also enjoyed his internship at Kees van der Westen's workshop, and who even works with KvdW's metal work engineer.