Some Like It Hot

On a recent trip to my friend Norm's house, I enjoyed espresso from the super-duper espresso machine at his house. I sold my Jura espresso machine when I moved into an apartment and didn't have enough counter space. At Norm's, I was reminded how much I liked a well brewed cup of coffee at home. My inexpensive Braun drip coffee maker was fine as far as drip coffee goes. With some Peet's house blend, I managed to wake up most mornings.

On a post-Christmas shopping excursion, my friend Jim commented about about how vacuum coffee pots brew coffee at just the right temperature. That got me on an investigation of coffee technology and how I might upgrade my drip experience. Here's what I learned.

There are three basic steps in coffee preparation: 1) roasting the beans, 2) grinding the beans, and 3) brewing the coffee. I expect that I'll always depend on coffee stores to take care of the first step, although some intrepid coffee nuts even roast their beans at home.

In the second and third steps, home coffee brewers have to make trade-offs between expense, time to brew and clean up, complexity, and taste preferences. So, if you are happy with the coffee your drip maker produces, stick with it. It's the easiest and cheapest method. You might improve the brew by grinding the beans just before brewing, but you don't even need a fancy grinder to brew a good cup. An inexpensive grinder will do just fine.

If you want to spend a lot of money and you have a lot of counter space, the Jura mentioned above does about as good a job as possible automatically grinding and brewing espresso at the push of a button. But don't think that the high-end machines take no work. You have to fill them with water and clean them just like any other coffee system.

What is available in between a cheap drip system and an expensive automatic system? This page has a good summary of the options: drip, French press, vacuum, Moka-pot, pour over (manual drip), and Aeropress.

Based on my friend Jim's comments and my previous experience with French presses, I started my search with vacuum coffee pots. This page has a detailed history of the evolution of the vacuum coffee pot. It is a case study in incremental improvements in a technology. The magic of vacuum pots is that they introduce the water to the coffee grounds at about 200 degrees Fahrenheit, a temperature deemed ideal for drawing out just the right coffee oils and chemicals. With manual vacuum pots, the brewer can steep the grounds as long as desired, so the brewer has great control over the strength of the resulting brew. Electric vacuum pots are easier than manual pots, but they lack brewing time controls. Much more on the trade-offs between manual and electric vacuum pots here.

Vacuum pots have three major drawbacks, though: 1) it takes time to make a pot, 2) it takes time to clean up, and 3) the parts break easily. The resulting coffee from vacuum pots is universally acclaimed, so vacuum pots are a great way to brew if you have time and you are careful. The current generation of vacuum pots incorporates a great deal of technology into very elegant designs.

Here's a beautiful old Sunbeam vacuum pot in action



I ended up buying the Aeropress, though. Why? Well, I don't have the Aeropress yet, so I can tell you only what I read. The Aeropress is a kind of upside-down French press that seems to avoid the thing I don't like about French presses, namely too many grounds left in the brew. Like the vacuum pot, the Aeropress receives universal acclaim for the resulting brew. Unlike the vacuum pot, the Aeropress is easy to use, easy to clean, and made out of plastic that won't break if you drop it. Both the manual vacuum pot and the Aeropress are portable, so you can take them camping and heat water on stoves or alcohol lamps. The Aeropress has an advantage that you can heat the water in a microwave, so it's simple at home and great for hotel travel.

After reading about how the vacuum pot brewed coffee at the ideal temperature, it was confusing that the Aeropress brews its best coffee at a temperature about 30 degrees cooler. The Aeropress people believe that the temperature difference may be a function of how the water cools as it flows through the grounds. My hunch is that different systems have different temperature and pressure points for optimal coffee extraction.

Oh, yes, and the Aeropress is about a third the price of a good vacuum press.

Having decided on a brewing system, I started learning about bean grinding. Or milling, as some would have it. The world of coffee grinders and coffee mills has the same trade-offs as the world of brewing systems. Coffee grinders that use blades are fine for drip coffee and may work okay for other brewing systems. The main advantage of the blade systems is price. The disadvantages are lack of consistency in fineness, and possible overheating and burning of the coffee during grinding.

The other way to grind, or mill, coffee uses burrs, and burr systems produce grounds of consistent fineness. Most burr systems available today use conical burrs. The first choice is a manual or an electric mill. In the electric mill world, the next choice is geared or non-geared. Non-geared electric mills are inexpensive, but can overheat like blade grinders do. Manual and geared electric burr mills avoid the overheating problem that blade grinders have. Manual has the disadvantage of longer grinding time, but the advantage of quietness. Geared electric mills are great, but usually noisy and always expensive. This Capresso grinder appears to be the same grinder as the one in the Jura above, and is currently the least expensive geared electric burr grinder I could find on the market.

I haven't figured out what coffee grinder to buy yet. I plan to try my blade grinder with the Aeropress to see what the results are. The next step is probably a manual grinder.

My surprise in the search for a good coffee brewing system was how hard it is to find a good solution, and how easy the solution I've found is. I'll follow-up after I've had a chance to try my Aeropress. Based on my reading, the best value coffee brewing system is an Aeropress using either a manual grinder or a Capresso geared electric grinder.

Here's how the Aeropress works.




Update: The Aeropress Espresso Maker is great. I noticed the difference when I upgraded from my blade grinder to the Capresso Infinity Burr Grinder. You can buy the more expensive silver version of the Capresso grinder, but the insides are exactly the same.

Medicine Light

Why are optics at the front of emerging new medical technology? Because optical techniques foster minimally-invasive health care.

Minimally-invasive optical procedures started in the first half of the nineteenth century with the endoscope. The endoscope provides physicians with diagnostic information, usually by snaking an optical scope and light through a natural cavity. If you've turned 50, you've likely had the pleasure of a colonoscopy, an endoscopic procedure that checks for signs of colon cancer.

In 1929 Heinz Kalk performed liver biopsies using a device he invented, a device that inspired the modern laparoscope. Kalk performed these "laparoscopies" using only local anesthesia and without mortality. Laparoscopes have evolved into a minimally invasive surgical tool for many kinds of abdominal surgery.

By 1944, Raoul Palmer had started filling the pelvis with air during laparoscopic gynecological exams. Then, in 1960, Kurst Semm invented the automatic insufflator. It sounds like a device to make perfect souffles, but it's really a device that safely pumps gas into the abdomen during a laparoscopy. In the 1970s and 1980s, the use of laparoscopy for gynecological procedures grew rapidly, especially with the introduction of integrated video technology in 1982.



A laparoscopic procedure such as a tubal ligation (see diagram above) can be performed in 10-20 minutes with small incisions under the navel through which the entire surgery takes place. Laparoscopy has had many benefits: less expensive and faster surgery with quicker recovery and lower mortality. Since 1990, doctors have adopted this minimally-invasive surgical technology to many other procedures like gallbladder removal, or cholecystectomy, and achieved the same benefits.

Another branch of minimally-invasive surgery uses catheters to perform procedures through small paths like arteries and urinary tracts. While not strictly optical devices, catheters are used for angiography. Experiments with catheters started on animals in the nineteenth century. Werner Forssmann won a Nobel prize for his pioneering catheter experiments in the 1929, in which he took an X-ray of a cathether in his heart. By 1997, Andreas Gruentzig performed the first angioplasty on a human. In this procedure, Gruentzig fashioned a balloon on the end of a Dotter catheter, which was used to position the balloon in a blocked artery. When the balloon inflated, it reduced the blockage.

In angiography, a catheter introduces a radio-opaque dye into the arteries of interest. Usually, the arteries of interest are in the heart or the brain. An X-ray clearly shows the arteries full of dye, and any blockage or bleeding. The angiogram below is of an arteriovenous malformation (AVM) which Senator Tim Johnson (D-SD) has made famous recently. If it's any consolation to Senator Johnson, my mother has recovered nearly completely from her AVM surgery.



Advances in computers and signal processing in the 1970s laid the groundwork for non-invasive imaging technology that has replaced most X-ray and angiography imaging. In 1972, Sir Godfrey Hounsfield invented the CT (Computer Tomography) scan, also known as the CAT (Computer Axial Tomography) scan. To make a CT scan, highly collimated X-rays beams are sent through the body axially. A computer processes the signals received from all beams and calculates a slice of the body. CT scans give significantly more information that X-rays and use less radiation. A CT scan shows the relative density of materials in the slice. CT scanning revolutionized the radiological diagnosis.

In 1980, Raymond Damadian made the first commercial MRI (Magnetic Resonance Imaging) device, which was orginally known as an NMR (Nuclear Magnetic Resonance) device until the marketing people decided the word "nuclear" might lead patients to think the thing was radioactive. The MRI scanner produces images by turning a magnetic field on and off, measuring the radio waves produced by atomic nuclei when the magnetic field is turned off, and computing a slice of the body. The calculations are very different than those for a CT scan, and the MRI scan shows concentrations of molecules rather than relative density. One advantage of MRI over CT is its ability to measure metabolism. I worked with a Ph.D. candidate who was measuring the metabolism of anesthetics in the brain in 1985.

The PET (Positron Emission Tomography) scan is a new twist on original CT scan.

Positron emission tomography, also called PET imaging or a PET scan, is a diagnostic examination that involves the acquisition of physiologic images based on the detection of radiation from the emission of positrons. Positrons are tiny particles emitted from a radioactive substance administered to the patient. The subsequent images of the human body developed with this technique are used to evaluate a variety of diseases. -- from RadiologyInfo

You don't want to know the physics behind PET scans. What's important is that PET scans have many applications including management of cancer treatment, detection of scarred heart muscle, and tumor detection.

Laser surgery is another innovation area in optical medicine. Most Americans have heard of Lasik (Laser-Assisted In Situ Keratomileusis) eye surgery, a quick procedure to improve eye sight. Lasers are popular for dermatology, too, especially removal of dialated superficial blood vessels. Less well known may be endoscopic use of lasers to remove tumors and for microsurgery applications, especially in neurosurgery. Fiber-optically delivered laser is used to vaporize and reduce discs in patients with herniated discs.

What are the emerging ideas in optics and medicine?

These days, researchers are experimenting with ideas like integrating MEMS and GRIN lenses to create non-linear medical optic systems (pdf). These systems may allow doctors to look at tissue in vivo microscopically, which would provide minimally-invasive diagnosis of disease without biopsies.

Fiber optic systems also could be designed to detect certain chemicals in the body, such as by-products from cancer or naturally occurring chemical reactions. If you put materials on the end of a fiber-optic line that react with chemicals you want to detect, you can measure changes in the reflection of a light off the end of the fiber optic to determine how much of the chemical is present.

Another area of minimally-invasive medicine revolves around photodynamic therapy. Photodynamic therapy may provide treatments for a range of diseases, from acne to cancer. For cancer, one idea is to introduce a photosensitive chemical that cancer cells absorb and that, when irradiated with otherwise benign light (or other electromagnetic radiation), kill the cancer cells.

In the catheter world, the FDA has recently cleared a device that removes blood clots from stroke patients. After an angiogram to locate the clot, a balloon is moved into place to block blood flow. Then a retriever (see below) captures the clot and the doctor pulls it out. As optics and nanotechnology provide smaller innovations, expect to see more surgical procedures delivered via catheter.



How all these emerging technologies make it into the medical market may be the largest problem of all. But that's for another post.

Happy Birthday, INGRES!

If you were born after 1976, you have never known a time without relational databases, a time when you couldn't build outside joins or conditional queries across multiple tables.

Last week I went to the 30th anniversary party for INGRES, the relational database invented at U.C. Berkeley. I went because I was the very first support engineer at Sun Microsystems to support INGRES. The event was really the anniversary of a paper titled "The Design and Implementation of INGRES". From left to right, the authors are Eugene Wong, Jerry Held, Michael Stonebraker, and Peter Kreps.

INGRES was the first broadly used relational database. 30 years ago, IBM (remember they owned the computer market then) offered a hierarchical database and AT&T (remember they owned the telecommunications market then) Bell Labs had just hatched UNIX. Recognizing that the big card reading computer on campus wouldn't work for their concept, Gene Wong remembered how the INGRES team was just able to scrape up enough money for a DEC PDP-11/45, the smallest DEC machine that would run UNIX. It cost about $100k.

Each of the four inventors remembered funny little stories, like the time the new 16-kB memory board blew up when it was installed upside down. Jerry Held gave a good overview of ten ingredients to commercial success. Mike Stonebreaker drew parallels between that time 30 years ago when IBM's hierarchical database technology failed to meet certain market needs, and now, when Oracle's relational database technology is running out of steam for applications like genomics.

The inventors complained that cuts in government R&D funding are stifling the kind of innovation that made INGRES possible.

The miracle is that these four guys, working in a university computer lab with scant resources, made such a gigantic change in the way our world works. 30 years later, relational databases are ubiquitous. You may well carry one in your cell phone.

The 30th Anniversary of INGRES was a good reminder that emerging new technologies rarely happen without Lady Luck. Edgar Codd had just written his seminal paper on a relational model for databases. The inventors chose UNIX without every having used it, and UNIX turned out to be one of the most popular operating systems. They distributed source code to other schools, a prescient move that spurred adoption of the technology. They ran into the resources, ideas, and each other at a time when the market demanded a better solution. All the stars lined up. The timing was right.