Kostverlorenvaart

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 S...

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,...

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 h...

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...

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!! 

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 #7 syringes 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...