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Tonino Unpacked and Unleashed

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The Tonino arrived. It's a new tool for coffee roasters to measure the color & darkness of their roast. Previously, such devices were very expensive (3000--15000 Euros) and only industrial roasters could afford to have them around. Roasters who couldn't afford the real thing, could settle for tiles in several colors representing values on the standard scale, so they could compare their beans during or after a roast to see how far they were off from their target coloring.

We are not schooled in cupping so if we want to know how our roast profile has done as soon as possible after a roast, Tonino is a very powerful tool. It gives exact numbers from a calibrated device.

The color example below is an alternative, but one never knows on what screen the designer made this chart, how it was calibrated, where he scanned the original color tiles from, on what medium, so it all remains guesswork and nothing to be communicated in a very meaningful way.

Primitive way to assess roast color/degree


Measuring roast color of ground coffee beans tells you more than just measuring the outside, because like a slab of beef can be roasted dark on the outside while being red inside, beans can be more deeply roasted or more superficially colored than you would guess on first sight.

Now, two guys in Germany have produced a small series of a roast color analyzer that is at least as exact at a fraction of the cost. Plus, their best customers donate 10% of the price to CoffeeKids, an initiative to help children in coffee producing countries. See their web site: my-tonino.com

I have unpacked the Tonino, calibrated it (very simple) and used it to compare two very different roasts. One light espresso roast of an Ethiopian coffee roasted on our modified Roastilino and one handful that a friend gave me which has come of his Gene roaster so dark it was almost charred. 

Package arrived!


The drawing on the outside of the Tonino was made by Sindy & José, two children from Guatemala supported by CoffeeKids at the Las Nubes Afterschool and Learning Center ADESPA
Box with manual and calibration pads, hand decorated Tonino, USB cable

Calibration: put Tonino on brown pad, then on red one, "done"!
Ground 17g of Ethiopia Cherry Red

Tamped grinds, grey card, roast profile

Ready for Tonino

Tonino's "eyes" resting on the coffee grinds

Measurement ready: roast value 91. That's a light espresso roast. Espresso is around 80, filter around 110, Nordic ultra light around 120. Charcoal Blackness would be around 60.

Proof of the pudding: espresso from this roast on the LONDINIUM

A fruity espresso
Now, on to the Very Dark Beans. They are actually darker than you see on the picture below, gloomy dark, oozing oil. Beans from Hell, sticky and smelling sharply like goat dung.
Beans from Hell

Roast from Hell: 36 on the Tonino scale. Alert the health authorities!

The dark roast on the left, the Ethiopian on the right, on grey card. With the naked eye you wouldn't immediately spot the dramatic difference between playful light Ethiopian beans and the lethal beans that could kill ya.

Espresso from Dark Matter. Flow very fast, an ashen brew with specks of soot

The same cup a few minutes later, smelling just as ominous and radiatinga threat to the house
 I also installed the free Tonino app:
Tonino app on the OSX desktop

This Tonino will allow us to evaluate a roast quickly after the roast is done, without having to wait several days for the beans to rest and breathe. Will be interesting to learn more!

Using the app, I have loaded an Agtron Commercial scale into the Tonino device, so I can approximate measurements as if they were made on the device of the very expensive market leader:

Loading one of the several standard scales
Other scales are those emulating Neotec ColorTest, Probat Colorette, Agtron Gourmet and ColorTest. The values then approximate those standard scales but in a lab / industrial application it would be best to also take a few samples on both devices to enable the Tonino to get finetuned. For us, it seems enough to be able to communicate values that are meaningful to people familiar with Agtron readings or Agtron tiles, while within our own little roastery we will be consistent as long as we keep the Tonino tuned to this current scale.

Using the Agtron scale enables us also to use other pages as a reference, such as

http://c3aflavorexperience.blogspot.de/2012/11/roasting-scale.html

Where we find this helpful chart. These charts are of course drawn up for people who could only wish to have a device showing Agtron compatible readings. They would use it to get an estimate of what an Agtron reading would be, we can see where our roasted beans reside in the roast spectrum on the lists and this knowledge, combined with tasting later, can help us refine the roast profiles or detect where we went astray.


Or this one:

(found on http://www.home-barista.com/home-roasting/how-to-roast-maui-mokka-t22765-10.html)

Another useful chart from http://www.coffeelabequipment.com/Color_Selector_cl.pdf :



Grinds in Heat

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With the Winter Olympics going on and especially the Dutch picking up so many medals in speed skating which is traditionally being regarded as the one competition defining the world pinnacle of winter sports, the focus of everyone's attention is temporarily lingering on the tv screens.

That's a good thing, because before you know it, everyday worries prevail again and we will once more hear about all the questions that keep people awake during the brief moments after switching off the lights at night before their dreams take over.

One of the questions one hears most often is "if the room temperature is 21º Celsius and we grind beans, how much warmer does the friction and cutting make the grinds?"

I decided to sort this out for my grinder, a Mazzer Mini fitted with Super Jolly burrs.

Turns out the temperature in the chute where the grinds pile up and move out is raised by one degree Celsius at the first dose that's ground. The second is about the same but the third and fourth raise the temperature another degree Celsius, all over a time span of about two minutes.

It does not make much sense to keep grinding away because this is a heavy grinder designed to be used in a home environment, not in a bar where one has rush hours and grinding goes on almost continuously.

I would like to hear how this is in other grinders though.

Preferably before the next Olympics. Just so we know. 

Hopper, anti-stat mesh and finger protection removed

Tiny T-type probe fitted, deep into the chute, just out of the burrs' grip

Funnel fitted

Amprobe logger connected
Artisan graph

Onze excuses voor het ongemak

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De mensen van Amber Alert stuurden vanochtend een chaotische mail vol HTML codes.

Vanavond kwam de verbeterde versie en daarin werd ook uitgelegd wat er mis was gegaan: het was een technische storing.

Dat is natuurlijk onzin. Wanneer de stoppen doorslaan gaat er geen mail uit, als alles het doet gaat de mail eruit zoals iemand het heeft ingesteld, en iemand heeft het verkeerd ingesteld. Maar het is voor zo'n organisatie onmogelijk te zeggen "sorry, we hebben vanochtend een foutje gemaakt, hierbij gaat-ie nog een keer".

 
Wat ik erger vindt is dat ze er rechts onder bij zetten "lees meer". Als je daarop klikt, zou je denken dat je "meer" te lezen krijgt, maar je krijgt exact dezelfde drie zinnen te lezen. Waarom staat er dan "lees meer"?! Als je het ze vraagt, is natuurlijk het antwoord "dat staat daar altijd meneer." Niemand komt op het idee dat weg te halen, of er neer te zetten "Lees hetzelfde nog een keer."

Staatsloterij kan er ook wat van:

Ook hier heeft niemand iets verkeerd gedaan, maar "er is een fout opgetreden." Aha, dat zal ik onthouden. Heb ik iets stoms gedaan en wil justitie mij straffen, dan leg ik het uit. "Er is een fout opgetreden edelachtbare, u kunt het als niet gedaan beschouwen, mijn welgemeende excuses."

Aanvulling 20 februari: vandaag in de rubriek "kan als niet verzonden worden beschouwd":

De laatste dagen is de helft van wat ik aan post ontvang reclame en de andere helft kan bij nader inzien "als niet verzonden worden beschouwd."

Ik kan beter alle post weggooien en pas wat doen als ik bericht krijg dat een bepaald bericht achteraf als WEL verzonden moet worden beschouwd.  

Roasting beans from Los Lajones in Panama

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Onno van Zanten kindly let me have 2kg's of beans from Panama, produced by farmer Graziano Cruz, a crop from his Los Lajones farm.

This time I tried two different profiles. First, the "stepped" profile that I've recently been doing minor variations of. These have delivered very pleasant beans so far.


The profile is built on advice from several people on Homeroasters and elsewhere. The idea is to quickly get up to serious drying temperature (130°C in 2 minutes), finish the drying phase at 160°C at the 5 minutes point, reach First Crack near the 7 minutes mark and allow 2 minutes development time while slowly climbing towards 222°C. It has given me successful roasts so far.

These beans smelled wonderful at the recent cupping and here at home they are quite delicious green as well, and they are the first I have roasted that smell just awesome very shortly after the roast, when they have cooled. In German one would say "umwerfend!"

I wanted to know if a straight line with a fairly constant Rate of Rise would do the beans even more good. With the current Roastilino setup that is quite easy to accomplish:



As you can see, both times the FC is about the same time & temp. Just 2 seconds difference could very well be my response time variance. I stopped the second roast about 12 seconds earlier because from the look & feel I got the impression the roast was at the point where I wanted to quit, keeping the beans relatively light espresso brown.

Smell was unbelievable again once the beans cooled off.

I packed them both and this time I could check the roast depth already with the Tonino:


They are fairly close, the first batch registered 57 on the Tonino's Agtron scale and the second one 65. My lightest so far even though with the naked eye I would not easily be able to tell the difference between these two batches.

I was not preparing coffee from the ultra fresh beans yet, so I just took 9g of each, ground on the HG One into the single basket so the top layer was still big enough for the Tonino to read.

Can't wait to do a Tonino read again tomorrow and maybe pull an espresso already. The smell is way too alluring to wait much longer.

PS 20 feb 2014:

I took both batches to Trakteren, where Erik, Edward & I did a cupping * espresso brew. For cupping the "straight line" profile was preferred, in espresso the slightly deeper "stepped" roast seemed better. We agreed that this is a fascinating bean that will probably be best appreciated by people who are very much into coffee. Maybe a bit too "special" for most others. 

I left the batches there, so maybe I will here more later.

Meanwhile I will try to roast the "straight line" profile a bit deeper without losing the special character of this bean.

Marko Luther suggested that we also put the Tonino-Agtron value on the labels, like we do with the profile and I want to do that. I must experiment a bit more with the best time to take that sample to measure, because the beans get darker as they cool down more.

VST Labs Coffee Refractometer & App

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How much of the coffee you ground has been sucked up by hot water and arrived in your cup to taste? Is it the considered optimum of 20%? You can bake your puck and weigh it later to guess, but you could measure it too and use a coffee cockpit of slides and gauges to navigate your next cup.

Here's a video by Matt Perger:



At the Coffee Company they also use a VST refractometer and the App from VST Labs to measure this:  (below is a snapshot from https://vimeo.com/84681146 )


We got one from the VST labs and did some first measurements. Turns out a cup we like, made with 15g of ground coffee beans, extracted 25g in 40 seconds on the lever machine, gave 8.8% TDS which is a bit low. Within the targeted Coffee Brew Formula but too weak on the given chart.

There's more to try with grind setting and dose to define the optimal mix of variables!







Espresso cooling

Filtered (right) through filter head on syringe (left)

Drops on the eye of the TDS, below the blue lid

Measures 8.8% TDS, a bit low on the green line in the Brewing Contro Chart on the iPad app

On the Home-Barista forum, I received some good advice from several different members:

Dick Green wrote:

Freshly-roasted beans may under-extract. That's because the beans are still outgassing and the CO2 interferes with extraction. You can test this by grinding a couple of doses, pulling one of the doses and measuring extraction yield, then holding the other dose in a plastic bag for a few hours, then pulling and measuring the extraction yield. Grinding will dramatically increase the rate of outgassing, so after a few hours you may be able to get higher extraction yields (though the cup may not taste as good.)

If you're pulling light-roasted beans, you may not be able to push the extraction yield beyond a certain point even if the beans have fully outgassed.

Bryan Truitt wrote:

If you liked the taste, it isn't under-extracted. 'under-extracted' is a qualitative description than can correlate to a range of extraction yields under certain brewing conditions. The coffee brewing control chart is a good reference but should only be a starting point for evaluation based on taste. For me, 20% tastes under-extracted on an Mahlkoenig EK43 grinder, not a Baratza Virtuoso. The quality of coffee and degree of roast also matters.

Longer flow will increase your extraction yield. The % TDS will go down. The calculation for the extraction yield is dependent on the measured beverage [...]. You can also increase yields for a given beverage size by grinding finer. Grind quality will often put an upper limit on the yields you can achieve for short shots—at a certain fineness your yields will go down.

Switching to fresher beans will lower extraction yields. Switching grinders changes which average extraction yields taste good by shifting the particle size distribution and extraction evenness.

Forget any expectations for brew time and just measure weights. Use good distribution technique and taste your shots at various yields and strengths and compare them. Experiment with much longer shots, like 36 or 72 grams. And don't be afraid to let short shots take more time than you are used to. For 'filter coffee' people often have very specific preferences for the strength of their beverage. The strength of the beverage which comes out of an 'espresso machine' is different at every cafe (unfortunately often within the same cafe). I have seen anything from 1.38% TDS to 20% TDS.
I like the idea of taking the freedom to vary and experiment, taste and then also measure the outcome.

On his blog Matt Perger posts a number of recipes on the espresso machine that vary wildly in TDS and extraction value. Some coffee is much more like filter coffee than typical espresso:

"Espresso Course –
Red Bourbon, Roasted on the lighter side of traditional espresso.
21g dose, 48g yield, 27 seconds, 9.5% TDS, 21.7% extraction.

Cappuccino Course -

Red Bourbon, Roasted with slightly more development and similar end temp.
21g dose, 50g yield, 27 seconds, 9% TDS, 21.4% extraction.

Signature Drink -

Espresso Component – Same as espresso course

Allongé – Bourbon, roasted slightly lighter and faster than the espresso.
20g dose, 100g yield, 25 seconds, 4.5% TDS, 22.5% extraction.

Lungo – Caturra, roasted halfway between traditional filter and espresso roasts.
19g dose, 150g yield, 25 seconds, 2.9% TDS, 22.9% extraction.

Coffee Shot – Geisha, roasted lightly, as we would usually for filter coffee.
18g dose, 300g yield, 30 seconds, 1.4% TDS, 23.3% extraction.

All of these extractions were very deliberate, and tuned for each roast style and strength of drink."
(He served these during the 2013 Championships: http://www.youtube.com/watch?v=ZgKgt2gtzD0)

---
Next I pulled & measured an Ethiopia Amaro Gayo that I find delicious in the cup, despite some passing sense of dryness. A pleasant mix of tastes that I find hard to describe so I won't delve deep to try it.

About one percent lower extraction-% and %TDS.

 Next, I tried the delicious Panama, Los Lajones beans on the Mahlkönig Vario grinder and the Rocket E61 machine, using 20g in the 20g-VST basket to brew 31.3g of espresso. This machine has a dual OPV so I could ramp up the pre-infusion at 4 bar, first drops appearing at 6 seconds, then up to 9 bar for 6 seconds and extracting the rest at 4 bar again.

A delightful, somewhat 'salty' taste:
  
Result:
Another photo impression of a measurement session:
Extraction:

Setup, with the Tonino that I use to measure the color of the grinds before the extraction:
 Half of the espresso to taste and half of it in a big cool cup to cool down


 Filtered espresso in the small heavy shot glass, taken out with pipette, drops on the refractometer:

Measurement done, ready to copy into the app

At Trakteren, a local coffee specialty place, I was invited to demo the setup and we did two measurements:

At home, I tried several extractions with Ethiopian "Cherry Red" beans that I roasted three weeks ago. At 16-17 % extractions these taste rich and spicy, like Dutch "speculaas" dipped in coffee, almond candy, and at slightly lower extractions it's a soft, light espresso. Both very enjoyable even though all of these were at lower extractions than the "box" of the app would have you expect.



Pas toch op uw man!

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Een gewaarschuwd mens telt voor twee
Het zal je maar gebeuren. Zo heb je een man en zo is-ie weg, sta je met lege handen. 

Met hele dure ras-katten gebeurt dat ook weleens, het zijn allemansvriendjes en je pakt ze zo mee. Zo lang ze goed te eten krijgen merken ze niet eens dat ze een ander baasje hebben.

En aangifte doen als je man is meegenomen is onmogelijk, zo blijkt telkens weer. "Je zal hem wel niet goed hebben verzorgd" wordt er meestal gezegd op het bureau en het loket gaat weer dicht. 

Vrouwen kijk toch uit. Wat er vaak uitziet als een vrolijke optocht met boten door je dorp is gevaarlijk. Houd hem binnen, ook als hij zegt "alleen maar een paar leuke foto's te willen maken."

Voor je het weet heb je het nakijken, ze zijn zo vingervlug, ze hebben hem te pakken eer je er erg in hebt en dan sta je er alleen voor.

Vigorous stirring

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The procedure for measurements as advised by VST labs is (in my words):

1) allow 1 minute for espresso to cool & CO2 to diffuse out of solution. Stir sample 5-6 seconds
2) with new unused syringe below crema, draw 3-4ml
3) attach filter
4) push 2 ml out into a glass, let cool 30s
5) draw 0.2-0.4ml in new unused pipette
6) transfer to sample well of refractometer
7) allow 20-30s to get temperature equal
8 measure (a few times)

I think the duration of the cooling times are merely indicative, or minimum times because for instance in the illustrations with the advise fairly small cups and glasses are used and I use small but heavy material with more mass on room temp to help cool down the fluids.

In the video by Matt Perger (http://www.youtube.com/watch?v=fL7vNbEcsxk), the stirring is done by vigorously sucking up and pushing out coffee using the syringe and that seems much more effective to me than stirring a few seconds with a spoon or the tip of the syringe.

In the video by Coffee Company of Amsterdam, step 4) is skipped: coffee is drawn into the syringe, the filter is attached and fluid is immediately pushed out onto the refractometer: https://vimeo.com/84681146 (see 2:08)

Yesterday, I tried drawing a large sample and then pushing out three times 2ml into three different glasses. The refractometer showed 14.6%, 14.7% and 14.8% on the three samples (Malabar), so the later bits out of the increasiningly saturated filter showed slightly higher TDS % rates.

On this sample of espresso, I also did the vigorous stirring using the syringe in-out routine mixing the fluid well. I will try this with other measurements as well, to see if this gets me (slightly) different results than just stirring a few seconds with a spoon or spatula.

Today I did the same stirring, with my favorite Panama Los Lajones beans from Graziano Cruz (Tonino # 96):

For the looks, the grind could be a bit finer still to get a little darker leopard-skin crema, but the taste is much to my liking. It reminds me of Indonesian coffee with Ethiopian 'unwashed' elements.


This was done using the Mahlkönig Vario grinder, and the Rocket E61 machine so I will need to do this a few times on the other configuration to see if it's the vigorous stirring that causes the TDS reading being higher or something else.


Hoe groot is een voetbalveld

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Vanmiddag was er vuur en vlam in Brabant.
"De natuurbrand die vanmiddag woedde in het Nationaal Park De Loonse en Drunense Duinen is onder controle. Het vuur is gedoofd, maar hier en daar smeult het nog ondergronds. De brandweer is nog enkele uren bezig met nablussen. De brand woedde op meerdere plekken in een gebied van 50 hectare, dat is zo groot als honderd voetbalvelden." (http://nos.nl/artikel/621487-grote-natuurbrand-in-brabant.html)
Bijna altijd als iets groot is, wordt er bijgezegd hoeveel voetbalvelden dat is.

Het ruimtestation ISS is zo groot als een voetbalveld. In het paarseizoen vergroten mannelijke mollen hun territorium tot de grootte van een voetbalveld. In New York is een H&M zo groot als een voetbalveld. De zee wordt leeggevist met netten zo groot als een voetbalveld. De oppervlakte van de blaasjes in onze longen is alles bij elkaar zo groot als... inderdaad.

Op tv zie ik soms een voetbalveld, maar ik weet niet hoe groot dat is. Als jongetje heb ik er weleens op gestaan, het was een eind lopen maar de bal ging overal naartoe, ik hoefde tot de rust nergens heen.

De brand heeft gewoed, het sein "brand meester" is gegeven, het nablussen is klaar, het ondergrondse smeulen is gesmoord. Het is donker en koud in het kale bos. Ik zou er willen gaan kijken morgen, maar het is een eind lopen, honderd voetbalvelden en je zit onder de zwarte vegen.
http://upload.wikimedia.org/wikipedia/commons/2/2e/Forest_fire_mae_hong_son_province_01.jpg





Filternatives

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I admit, when I ordered his VST Refractometer, Vince from VST labs already suggested I might order extra syringe filters but at the time, 50 of those seemed a lot to get started. Of course I rushed through most of them in the first week so I ordered 50 more. They don't come cheap though: $89 for fifty plus $34 for shipping to NL.

As I ordered 500 pipettes and a box of #7syringes locally from Hinmeijer, I wondered if compatible filters could also be found nearby. René Hinmeijer is looking into this and Adriaan, a fellow roaster from the Dutch forum, quickly found a possible alternative from an Asian company reselling German filters: Minisart by Sartorius. These cost me not much more than the postage of the original VST filters. They are "high flow" syringes with 0.2 micrometer pores. I do not know the pore size of the originals though.

Since the special filters are not necessary when measuring coffee that has passed through paper filters, like drip coffee, I also got a Hario V60 Dripper.

If the measurements of the VST and the German filters come close, the latter would be a great alternative and if a particular measurement is most critical, I could double check the measurement with the original filter, to be sure my readings are compatible with what others would get with the same lab standard.

I took 20g of Finca Tamana beans roasted 17 february (Tonino # 84 today) and pulled 30g espresso. Cooled in a larger ceramic cup, stirred well, filled two identical syringes, screwed a VST on one, a Minisart on the other and pushed a few ml's with each into their own identical shot glass.

Even though the Minisart is a "high flow" filter, it took much longer (and more power) to push enough fluid out of it. Afterwards, on close up pictures of the filter, it showed two cracks. I can understand why the manual advises to "take care when using syringes with a volume less than 10ml since they can generate a pressure greater than the maximum operating pressure of the Minisart unit."

Next I took two brand new pipettes and did my measurements after first calibrating the refractometer and cleaning the eye of the meter with alcohol between measurements.

The Minisart sample showed 11.1 % TDS and the VST sample showed 11.2 % TDS.

So that's very very close and if subsequent comparisons turn out as good, this will be a fine alternative as long as I keep my glasses on and take care not to explode the filters.

The drip alternative (the leftover poured onto a filter which I made wet with tap water first) showed 9.8 % TDS on the first ml's that passed. I should try this again, this time on a dry filter paper and with more espresso, taking the time to let it all drip through.

Extraction ready to measure
VST filter and Minisart sister

Two samples from same extraction
Minisart after use, notice the hair cracks
Both syringes & filters after the job
Result of VST measurement visible
The drip test, not as close to the original: diluted & not fully filtered yet

We thank G

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A stairway in the Amsterdam Museum of Photography "Huis Marseille".
Someone has carefully lettered a message on the wall, maybe explaining something about a picture nearby. Someone else has rushed to wash off most of the message. The word 'Russia' is barely legible along the remaining smudges but part of the message survived.
"I thank G"
Who is G? What has G done for us? We don't know but it's the best sign I've seen in the museum today. Thank you G! Thank you!! 

Espresso Centrifuge

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Still trying to learn more about the filters to use in espresso filtration for refractometer measurements I emailed Wybo Dekker, a friend who has conducted chemical analysis all his life until his recent retirement. For many years he had his own consultancy firm. We have both been board members of the Dutch language TeX user group NTG and when meetings were held in his monumental home built long ago on a dike along a small river, I was always impressed with the ultramodern chemistry tools here and there in this beautifully restored old house.

Wybo could not tell me much about filters but he did have a brilliant offer:

"No, I was never seriously involved in these little filters so I can't tell you anything about them. As a matter of fact I hate filters --- they tend to get clogged on the most inconvenient moments, especially if for some reason you want to filter out relatively small particles. 
That's why I prefer to use an excellent centrifuge. I've got one here -- up to 4000 rotations per minute, electronically controllable, programmable including rates of accelleration and slowing down to avoid any turbulence during those phases. 
I have no clue as to what you're trying to accomplish with coffee, but if it is of any use to you you're welcome to have it.Mind you, it's a heavy thing measuring 40x45x50cm."
I was quite thrilled of course and in a hurry to pick up this gem. Until I had time to do so, I read the PDF of the manual which was available online and I watched some online video's about centrifugal separation. A machine like that needs careful treatment because even with relative small amounts of fluid rotating at thousands of RPM, the G-forces can be substantial and an imbalance can cause havoc.

So here it is, the Espresso Centrifuge next to the Londinium I:

Hettich Rotanta /P Centrifuge
On the back it has what looks like an RS232 port so who knows what I can yet discover about its remote control options. Wybo also gave me a number of little glass tubes to load the espresso fluids to separate from the tinest floating coffee grind particles, and a couple of very smart volumetric pipettes which can suck up and deliver a very precise volume of fluid, to the thousandth of a milliliter. He rarely used those but I think they look rather geeky so they were a must-have.

Time to brew some espresso! I used 20g of the Panama Los Lajones from Graziano Cruz which I roasted two weeks ago. Got 30.3g extraction:

30.3g of espresso from 20g grinds on the Londinium I



Next I weighed off 7g of the (stirred) espresso in a test tube and also 7g of water in a matching test tube:
Two identical test tubes, both filled with 7g, one water, one espresso
I placed these on opposing sides in their containers on the rotor, so the centrifuge will not have any imbalance:

Coffee and water of equal weight in matching seats, ready for the ride
Setting breaking force to 3 (out of a scale from 0=free running to 9=full brakes) and target speed of 3000 RPM, no pre-set running time:
Break force 3, rotation speed 3000 per minute, ready to start
The machine revved up slowly, gradually accumulating RPM speed and the digital dials showed actual speed and time since start.  After 4 minutes, at the STOP button the machine slowly calmed down and all signs blinked when it was safe to open and take out the sample.

I measured the sample straight from the test tube, using a new pipette onto the calibrated refractometer and read 9.6 % TDS:
9.6% TDS on sample out of centrifuge
Then it got a little more exciting still. I took a new sample out of the same espresso cup that had yielded the sample that I just measured, using a new syringe and a new VST filter and used a new pipette to put drops on the (cleaned) refractometer:

Yay! Filtered sample out of espresso source gives identical reading
This is nice. The filtered sample gives the exact same result on the refractometer, which indicates for now that the centifuge method of separation is effective enough to work with.

I will need to do more testing and I will specifically be trying to find out the best rotation speed and the optimal duration of the centrifugal separation. There was some sediment visible in the bottom tip of the test tube but I think the fluid could be separated even better. And then I could save this sequence into a numbered program, including the time to reach max RPM and the time to slow down to the full stop. I will then be able to reproduce the exact same procedure every time.

With this machine I can skip filtration if I want to.

Thank you Wybo for this beautiful device!

 

Zentrifugalbeschleunigung

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I'm so happy with this machine, in part because I learn beautiful new words from the manual, like Zentrifugalbeschleunigung. Abbreviated RZB for relative Zentrifugalbesleunigung. It's the German word for the g-force endured by the sample that's spinning around the centrifuge axis.

The synonym is just as beautiful: Schleuderziffer. With technical manuals like this, who needs poetry?

This value is more meaningful than just the RPM (rotations per minute) because a compact sample spinning closer to the axis experiences less centrifugal force than a sample that's hanging further away from the center of the rotor.

The machine has a display / keypad combination to enter these values and then it calculates and displays the realtime Zentrifugalbescheunigung during the procedure.

The previous owner never used the programmable options (he just inserted a sample, set the speed, pressed start and after a given time pressed stop) so I found it especially thrilling to have the machine activate this part of its capabilities for the first time.

I also measured the exact distance of the top of the fluid to the axis/center of the rotor and to the bottom tip of the fluid in the glass tube. If this value is fed into the machine it not only displays the rotations-per-minute but also the relative centrifugal force on the sample.

In the current program, the machine takes 60 seconds to slowly build up a speed of 3500 RPM, maintaining this speed for 7 minutes before braking at a very moderate force aiming to come to a full stop in 120 seconds, and below 500 RPM there is no braking force anymore, just free running slowing down to a full stop.

I measured the ambient temp, took 20g beans for the VST 20g basket (grinds measuring #99 on the Tonino scale), extracted 30.3g using the Londinium (releasing steam just before locking in the PF to activate the heating element to build up maximum pressure in the boiler / pre-infusion, lowering the lever again as the first drops fell from the naked PF, so a sort of "Fellini move" to get extra pressure on the first moments of extraction), stirred the extraction vigorously with the syringe, taking a 7g sample for the centrifuge, a 5g sample for the VST filter and drinking the rest.

Before this, I weighed the glass tubes until I matched two that are 15g each. I filled one with 7g water, the other with the 7g espresso and ran program #1 specified above.
Ready to measure

Meanwhile I calibrated the VST refractometer with distilled water from the old precision lab fluid dispenser in the picture (a very nice contraption of fragile glass tubes into valves and a volumetric regulator).

Then I stirred, VST-filtered and measured three times the sample I saved: 10.9, 11 and 11, so noted 11% TDS

Next I took samples (with different new pipettes) from the very top of the centrifuged sample, from the middle and from close to the bottom: 11.1% -- 11.2% -- 11.1% so it seems it doesn't matter much how high or deep I go to get my sample with the pipette.

Noting the VST filter sample as 11% TDS and the centrifuged sample as 11.1% I would get 17.3% or 17.4% extraction (rounding off to one decimal).

Again, the centrifuge seems a fine alternative to filtration.

Measurements ready

Below is a picture I made yesterday of the sediment in the glass tube. I would like to weigh it but it's probably so very light, the few remaining drops of fluid in the tube will probably weigh more so it would be hard to estimate the weight of the sediment.
 
Weighing the residu can be quite a task, Wybo writes me in Dutch. It involves washing a few times with a few ml's of distilled water (along the inside wall of the tube), centrifuge this off a few times, decant, then dry in a desiccator, weigh, clean tube and weigh again, using a precision balance to 0,1 of a milligram...

"Gewichtsbepaling van het residu is inderdaad lastig. Je zou het eerst
twee of drie keer moeten behandelen door:
1. spoelen met een paar milliliter gedestilleerd water (langs de
  buiswand rondom naar beneden spoelen,
2. Afcentrifugeren
3. Decanteren
En tenslotte drogen in een exsiccator, wegen, buis schoonmaken en
opnieuw wegen. Je houd maar een paar milligram over, waarvoor je dus een
balans nodig hebt die tot tiende milligrammen of minder gaat."

Indonesia Raja Batak

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Measuring setup. Filters & alcohol swipes & pipettes, centrifuge tubes & stoppers, refractometer, espresso, fountain pen, notepad, distilled water dispenser, Amprobe temperature meter, Tonino color analyzer for coffee grinds, scale, Indonesia Raja Batak beans.
Pulled, tasted and measured three espressos from Indonesia Raja Batak beans roasted 13 days ago, Tonino # 93 today.

All three with 20g beans, from the HG One grinder in the VST 20g basket. Used the flat tamper to measure the Tonino value but the convex tamper before the extractions as I get a more even flow then, mostly. 

Extractions were 30.3g, 30.5g and 30.3g (first second and third pull).

I used the same centrifuge program for all three 7g samples taken from the espresso shots.

The first measured 10.4% TDS = 16.3% extraction, and tasted nice but a bit thin for these beans which can be beautifully complex spicy.

With a bit finer grind, the next measured 10.9% TDS = 17.11% extraction, tasting great, a very pleasant mouthfeel although I have had more of a wealth of taste from these beans a while ago.

The third shot with a little finer grind still (about as much finer as the first turn on the grinder) measured 10.8% TDS = 16.96% extraction and the taste had a slight dryness now.

It surprised me that the finer grind did not create a larger yield. Possibly the fines now clogged up the flow besides allowing more extraction, but there may be lots of other things I haven't considered yet.

Next time I taste a dryness, I will try a slightly coarser grind and a shorter shot.




Comparing filters, centrifuge and no filter

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Someone asked me what's the difference between filtered and unfiltered espresso on the refractometer and I had to admit I hadn't thought "out of the cup" yet and never tried.

Now I did: I took 18g of a dark (Tonino #63) blend in the Reneka basket, ground it a bit too fine I guess and had a very slow extraction which I helped a bit by pushing up the lever on my Londinium. 29g espresso out.

Calibrated the VST refractometer at 19.9°C ambient and temp climbed to 20°C in the process so no need to recalibrate before I finished.

I poured the espresso into a large heavy cup and swirled to get it to cool down relatively quickly, then took measurements, after that put 7g in the centrifuge and repeated the measurements, adding the centrifuged one.

Before using the filters, I sucked up and pushed out the espresso with the syringe to get an optimal mix and I pressed out the drops straight onto the VST prism. Pressed GO three times on all samples.

SA=Sartorius filter

Shortly after half-cooling down:

VST filter: 9.5%
NO filter:  9.6%, 9.7%, 9.8% then staying 9.8%
SA filter:   9.6%

Then I did the centrifuge and after 10 minutes when the centrifuge was ready, using fresh filters on the more completely cooled sample, stirred well again:

VST filter: 9.8%
NO filter:  9.9%
SA filter:   9.8%
Centrifuged sample: 9.8%

I would need to do this more often, and preferably hear from others who are able to repeat this, but to me it indicates that a filter is useful, the VST filter assures you you are measuing the same way as the next guy, the cheapo filter I found is okay, but even NO filter works with just a small error if you stir very well and use a thoroughly cooled sample (and clean the refractometer well).

Stephen Sweeney's TPF - Transparent PortaFilter

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Stephen Sweeney from Seattle enjoys some fame in the espresso world for a number of custom made modifications he has made: transparent acrylic super-magnetic bases for baskets and portafilter holders for the HG One grinder to fit the portafilters for Londinium, La Pavoni and other machines, for instance. And, for the HG One and other machines, beautiful wooden handles.

Fewer people know that he is also a designer and builder of canons. Real working scale models like this 1867 Whitworth 40mm rifled breech loader:


He has taken this canon and others to competitions where the builders got a chance to demonstrate the functional precision of their cannons, hitting objects far away in the distance. When he was on his way to these competitions, tailgaters (people following too closely) were pretty shocked to find themselves staring down the barrel of a large cannon!

He also builds custom kayaks:


So you will not be surprised I placed my hopes on Stephen to make me a unique tool to study the invisible: whatever is happening inside the metal filter locked in the portafilter during espresso extraction.

I got the idea from two short and crude clips published by La Spaziale:




It surprised me that so far there are just these two clips, but after corresponding with Stephen and getting the updates on his first TPF model and the next one, I got a better understanding of the problems that arise when building such a one-off tool.

One needs to find a way to replace both the wall of the portafilter and the basket itself with something transparent, but it needs to hold the metal bottom of a normal filter basket. Also, the top should lock in securely to the brew group. Then, the combination of very different materials (metal, acrylic, sealant) must be able to all hold together in temperatures rising and falling very quickly from room temperature to temperatures close to the temperature of boiling water, and huge pressure differences from the pressure in the room (on the bottom) to 8 or 9 bar (at the top). Plus, a coffee puck tamped inside, air and water flowing around...

I can now imagine how the Spaziale team would maybe have felt the urge to push further and use their TPF more, but it's possible that it didn't hold that long and the manager, looking at the cost in time and materials, likely veto'd any further exploits.

Stephens final TPF held out during a few tests in his workshop and it stayed in one piece during fifteen tests Roemer Overdiep and I did in Amsterdam on the Londinium I lever machine, but then it too began to give. One side is starting to pop open and from what I heard from Stephen, you do not want to be standing very close, peering at the looking glass, when it pops open en explodes hot water and coffee grinds in your face.

Before we started documenting these TPF experiments, we rented a Sony 4K High Speed camcorder. It fits the Canon prime lenses we have available so we would not miss any detail.



Roemer is working on the footage and although editing it all will take some time, he expects to be able to send me a first clip within a day or two.

From what I have seen on the small monitor I can promise you it's mighty spectacular. The slow storm raging inside the TPF is beautiful to behold.

We also learned something we would maybe not have found out without the TPF: when using a tamper that fits very tight, it's best to tamp lightly. After finishing a firm tamp and pulling back the tamper, the puck can be pulled loose along the sides and this results in the puck jumping up and being slammed down again when the spring lever is being pulled. In a pump machine the puck will not jump up of course, but the seal along the outside of the puck will allow some initial flow.

The "puck jump" happens very fast but is very clearly seen when we use the super slow motion feature of the camera. It hardly causes a problem but to get a nice and even flow when using a very tight fitting tamper, tamping lightly seems advised.

When we used the tamper that fits my millennium La Pavoni Europiccola, that proved a very nice fit for Stephens TPF and the puck remained still, allowing the raised piston to suck in air through the puck instead of along the sides. Sadly, by the time we figured that out, the life cycle of the TPF was nearing the end and we couldn't risk damaging the $10.000 camera...

For a short moment (elongated in the footage) there's a lot more coffee flying around in the TPF than I imagined there would be, but very swiftly, once the pressure is applied, all clears up and you can see the tiniest stream of water along the grains of coffee grinds and air and CO2 struggling to get out of the way.

We cannot thank Stephen Sweeney enough for making this little project possible!

Watch this space for more.




Stephen Sweeney's TPF -- video's

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Stephen Sweeney's TPF - Transparent PortaFilter from Roemer Overdiep on Vimeo.

Stephen Sweeney from Seattle enjoys some fame in the espresso world for a number of custom made modifications he has made: transparent acrylic super-magnetic bases for baskets and portafilter holders for the HG One grinder to fit the portafilters for Londinium, La Pavoni and other machines, for instance. And, for the HG One and other machines, beautiful wooden handles.

READ MORE...

http://kostverlorenvaart.blogspot.nl/2014/03/stephen-sweenys-tpf-transparent.html

---
Made by Frans Goddijn & Roemer Overdiep
This video is not graded and is native slowmotion.

Music: 06. Alexandre Desplat - The New Lobby Boy

Lewis & Lovack

Transparent PortaFilter - EXTRA FOOTAGE - Stephen Sweeney's TPF from Roemer Overdiep on Vimeo.

TWO EXTRA TAKES FOR THE COFFEE NERDS ;-)

Stephen Sweeney from Seattle enjoys some fame in the espresso world for a number of custom made modifications he has made: transparent acrylic super-magnetic bases for baskets and portafilter holders for the HG One grinder to fit the portafilters for Londinium, La Pavoni and other machines, for instance. And, for the HG One and other machines, beautiful wooden handles.

READ MORE...

The original posted movie:
https://vimeo.com/89652511

kostverlorenvaart.blogspot.nl/2014/03/stephen-sweenys-tpf-transparent.html

---

Made by Frans Goddijn & Roemer Overdiep
This video is not graded and is native slowmotion.
Music: 06. Alexandre Desplat - The New Lobby Boy
Lewis & Lovack

Slomo Olloclip espresso

Bolt-Efeu "Premsela" vulpotlood

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Op vrijdag 17 augustus 2012 overleed op 94-jarige leeftijd Bep Premsela, een lieve, milde, zeer ontwikkelde en knappe vrouw, weduwe van Robert "Boet" Premsela die vijf jaar eerder op 92-jarige leeftijd was gestorven.

Samen hadden ze vele jaren een boekhandel, gespecialiseerd in boeken op het gebied van beeldende kunst, vormgeving en architectuur, die vandaag nog bestaat. Ik citeer uit het Boekblad:

Alleen Boet en zijn jongere broer Benno overleefden de Tweede Wereldoorlog; zijn ouders en zuster waren in Auschwitz vermoord. Na de oorlog trouwde Boet met Bep Boas en in het eerste naoorlogse jaar overheerste een overweldigend gevoel van vrijheid. 'Vrij zijn betekende voor ons je bezig kunnen houden met dingen die je interesseren, vertelde Bep in een interview, 'in ons geval boeken - zonder daarbij iemand boven je te hebben. We wilden alleen maar verantwoording afleggen aan elkaar.'

Ze woonden vlak achter het Concertgebouw, een statige, rustige buurt. Hoe wijs en vriendelijk ze ook was, Bep kwam in actie wanneer iemand in de omgeving zich in haar ogen niet wellevend gedroeg. Ook een nieuwe buurvrouw die voor veel overlast had gezorgd en die met een bos bloemen bij haar aan de deur kwam om zich te verontschuldigen, kreeg een strenge vermaning.

De laatste jaren had ze, ook door problemen met haar rug, minder tijd voor het onderhoud van haar tuin. Toen ze was overleden, verzochten enkele buren me om de klimop die vanaf haar tuin huizenhoog was gegroeid te ruimen, omdat het vallend gebladerte hinder gaf. Ook twee bomen zouden ze graag weg hebben. Een inspecteur van de gemeente gaf gelukkig geen toestemming voor het rooien en hij wees me vertrouwelijk op een zeldzame varen. Als hij die in zijn rapportage zou opnemen, mocht er sowieso niets meer aan de tuin worden veranderd.

De klimop is wel weggehaald. Hij werd te groot en zou het dak van het huis hebben getrokken. Willi Egger, een multi-vakman, van oorsprong veearts maar intussen ook timmerman, boekbinder en typograaf (hij verzorgde de typografie van Het Voorbeeldige Boek van Johan Polak), sneed op mijn verzoek een stuk van de vuistdikke stam van de oude klimop van Bep Premsela.

Nu heeft hij het hout, dat bijna twee jaar heeft kunnen drogen, gebruikt om een bijzonder fraai en dierbaar vulpotlood mee te maken:

Bolt-Efeu vulpotlood "Premsela"
Dankje Willi!

Sturen en dromen

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Wie stuurt, zit doorgaans fier rechtop. Veel verkeer zie je in de verte aankomen maar er kan vooral op de grachten in het centrum uit een dwarse gracht ineens een gigantische rondvaartboot komen en die stuurlui zijn meedogenloos.

De partner zit eerst naast de stuurman maar naarmate de tocht vordert, gaat de voorplecht lonken en zeker als de zon schijnt is dat de plek om je te laten vallen, alles te vergeten en de dromen op je af te laten komen.

Als er nog een derde persoon aan boord is, is dat vaak de toeschouwer, die kijkt naar de stuurman, de dromer, of de kade.




The Last Blast

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THE LAST BLAST from Roemer Overdiep on Vimeo.

Stephen Sweeney built us a Transparent PortaFilter and the first two video clips we made were eye openers for many coffee aficionados. Still, there is more to clarify by using Sweeney’s TPF. For instance, we would like to check if a less tightly fitting tamper would ensure the puck remains in place when the piston is raised on a lever machine.

This weekend we set out to film more, starting off with the Rocket E61 machine. The calm trickle of water above the puck was a bit of a surprise to us, as it demonstrates how on such a machine the pre-infusion and pressure buildup is very gentle and gradual.

Alas, the TPF burst after 1.5 shots so that was all the footage we were able to record for now. Hopefully we will be able to do the rest later this year. Again, we thank Stephen Sweeney for providing us with his TPF!

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