Coffee Cupping Is A Grind — Spectroscopy Could Brew Better Beans

May 1, 2021 by 18 Comments

If you’ve ever bought whole coffee beans, chances are good that there was all kinds of information on the bag that led to your decision, like the origin, the roast type, and the flavor notes. Traditionally, coffee grading — that’s judging the aroma of both dry and wet grounds and slurping the coffee evenly across the tongue to determine the flavor profile — is done by humans in a process called cupping. To call it a process is too clinical — it’s really more like a ceremony performed with the grave sincerity that coffee deserves.

A traditional cupping ceremony. Image via Kaldi’s Coffee

There’s an industry standard coffee flavor wheel, so why not leverage that to make a robot that can remove the human bias and possible error of doing things the traditional way? That’s exactly what Demetria, a Columbian-Israeli company is doing.

They’ve developed an AI platform that can determine bean quality as judged by handheld scanners that were born on Kickstarter. The scanner uses near-infrared to look for biochemical markers in the bean, which it uses to match up with a profile backed by the all-knowing coffee flavor wheel.

Demetria is using SCiO scanners and a custom app to judge beans before they’re even roasted, which greatly speeds up the process but makes us wonder how green bean spectroscopy stacks up against roasted beans as judged by humans. You may remember the SCiO, a pocket-sized, connected spectrometer made by Consumer Physics that finally started delivering the goods a few years after funding. If you got your hands on a SCiO, you might like to know that there’s an open project out there to hack them. Sparkfun did a nice, thorough teardown, and it seems to be a well-engineered piece of hardware.

On the one hand, cupping is a tradition and thus may people feel that robbing coffee of this tradition will rob coffee of its soul. On the other hand, cupping is wasteful, as the coffee must be roasted and ground immediately prior to the ceremony and it requires the availability of Q graders who have been trained in the ways of coffee grading.

Want to know more about coffee production? Might as well learn the Retrotechtacular way.

[Main and thumbnail images via Demetria]

How To Cobble A Wobble Disk Roaster Together

March 14, 2021 by 9 Comments

As with anything else, once your knowledge of coffee expands, the more attractive it becomes to control as much of the process as possible. Buying whole beans and grinding them at home is one thing, but you’re not a real coffee geek unless you’re buying big bags of green beans and roasting them yourself in small batches.

[Larry Cotton] has made an even more portable version of the wobble disk roaster we saw last summer. Beneath the housing made of aluminium flashing is the guts of a $15 Harbor Freight heat gun pointing upward at a metal strainer. A large metal disk mounted at a 45-degree angle to the spinning axis tosses and turns the beans as they get blasted with heat from below. [Larry] used a 12 VDC motor to run the wobble disk, and an an adapter to change the heat gun from 120 VAC to 12 VDC. This baby roasts 1½ cups of beans to city plus (medium) level in 12-15 minutes. Grab a cup of coffee and check it out after the break.

Roasting beans isn’t rocket science. Even so, there are some things you would benefit from knowing first, so here’s our own [Elliot Williams] on the subject of building DIY roasters.

Continue reading “How To Cobble A Wobble Disk Roaster Together” →

Tired Of Popcorn? Roast Coffee Instead

February 25, 2021 by 17 Comments

We’ve seen a lot of coffee roaster builds over the years. [Ben Eagan] started his with a hot-air popcorn maker. If you think it is as simple as putting beans in place of the popcorn, think again. You need to have good control of the heat, and that requires some temperature monitoring and a controller — in this case, an Arduino. [Ben’s] video below shows how it all goes together.

With the Arduino and the power supply strapped to the sides, it looks a bit like something out of a bad post-apocalypse movie. But it looks like it gets the job done.

In addition to the Arduino, a thermocouple measures the temperature and that takes a little circuitry in the form of a MAX31855. There’s also a relay to turn the heater on and off. There are other ways to control AC power, of course, and if a relay offends your sensibilities you can always opt for a solid state one.

Continue reading “Tired Of Popcorn? Roast Coffee Instead” →

Pulse Oximetry Sensor Judges Your Coffee Roast

October 22, 2020 by 24 Comments

Breakout board for the MAX30101, which [Zach] used as the basis of his roast gauge. The sensor is at the top edge of the board.
Parts designed and marketed for a specific application can nevertheless still be useful in other ways, and whenever that happens, it’s probably the start of a pretty good hack. Using a sensor for something other than its intended purpose is exactly what [Zach Halvorson] did to make the Roast Vision device, which uses the MAX30101, a sealed optical sensor intended mainly for pulse oximetry and heart-rate monitoring.

[Zach] is instead using that sensor to measure the roast level of coffee beans, and assign a consistent number from 0 to 35 to represent everything from Very Dark to Very Light. Measuring a bean’s roast level is important to any roaster seeking accuracy and consistency, but when [Zach] found that commercial roast gauges could easily cost over a thousand dollars, he was sure he could do better.

[Zach] settled on using a Sparkfun MAX30101 breakout board to develop his device, and Sparkfun shared an informative blog post that demonstrates how making hardware and tools more accessible can help innovative ideas flourish. The Roast Vision device has a 3D printed enclosure, and a simple top-loading design with an integrated sample cup makes it easy to use. One simply puts about a teaspoon of finely-ground coffee into the sample cup, and the unit provides a measurement in a couple of seconds. Fortunately the sensor works just fine though an acrylic window which means the device can be sealed; a handy feature for a tool that will spend a lot of time around ground coffee.

The joys of fresh roasted coffee is something that is perfectly accessible to those making small batches at home. There are commercial options for small roasters of course, but should you wish to go the DIY route, check out our own Elliot Williams’ guide on making a low-cost DIY roaster.

Accurate Coffee Billing Through Reverse Engineering

May 31, 2018 by 37 Comments

If you’ve ever worked in a stingy office, you’ve become familiar with the communal coffee maker that runs on some variant of the honor system. There’s bits of paper, a coin jar shabbily sealed with sticky tape, and the routine note every six months telling people off for not paying for their daily brew. It all gets a bit much. Thankfully, if you work with [Fabian], it’s no longer a problem (PDF link).

The project forms the basis for [Fabian]’s thesis, in which a DeLonghi coffee maker is reverse engineered. This is undertaken with the explicit goal of properly metering the amount of consumables (coffee beans) used per beverage, to more fairly charge users depending on their brew of choice. This involves breaking down and understanding the coffee maker’s internal communications, as well as implementing a system to record and handle billing. For reasons of simplicity, [Fabian] decided that this should be handled using his colleague’s existing computer accounts. Easy!

It’s a highly academic approach to what we’re sure was a very stimulating project with lots of delicious aromas. Coffee’s a popular topic among hackers, that’s for sure – check out this roaster to take your game to the next level.

 

DIY Coffee Maker Filters Out Manufacturer Specificity

June 7, 2014 by 12 Comments

Coffeemaker made from 3D-printed parts and scrap aluminium

This DIY electric coffeemaker prototype uses an assemblage of 3D-printed parts and cast aluminium. [siemenc]’s main goal with this project was to utilize and demonstrate recycling and re-usability. He used Filabot filament exclusively and melted down scrap aluminium such as cans, foil, and CNC mill waste in an oven he fashioned from an old fire extinguisher. He also cast the aluminium parts himself from 3D-printed positives.

Of course, he had to buy the things that make this a coffeemaker such as the hoses, the fuse, and the heating element. If you’re wondering why he didn’t salvage these parts from yard sale machinery, it’s because he wanted to be able to replace any part of it and have it last as long as he needs it to last. The innards he used are not specific to any model, so he should be able to easily find a replacement.

Just like a pour over set up, [siemenc] has fine control over the strength and quantity of the brew. We particularly like this machine’s exotic bird looks as well; it may be a prototype, but it’s quite stylish. If you’re looking to go all the way with DIY coffee, why not grow your own beans and then roast the beans yourself?

 

Grow Your Own Coffee Beans

September 2, 2013 by 47 Comments

beans

Unlike T-shirts, sneakers, cell phones, children’s toys, software, appliances, virtually everything made of plastic, and food, people really seem to care about who makes their coffee. Instead of buying guilt-free free trade coffee, [spikec] over on Instructables decided to actually do something to uproot the evils of consumerism. He’s making his own coffee, at home, with a real coffee plant.

[spikec] bought a coffee plant a few years ago off eBay. Coffee plants are actually trees, and with careful pruning they can be maintained to a reasonable size. But what about the weather? Well, for [spikec], who lives in the 7a USDA hardiness zone – a strip that runs from southern New Jersey to the Texas panhandle – he just brings the plant inside when it’s cold.

Once the coffee fruit turns ripe, [spikec] picks the beans, husks the fruit, and puts the beans in a dehydrator. From there, it’s a trip through a small coffee roaster and into a french press.

[spikec] only harvested about a half pound of beans. That’s still very impressive for growing a bonsai coffee tree a thousand miles outside its native range.