Saturday, December 3, 2022

BH Unlimited Update - Dec 3rd 2022

Thermal Energy

BH Unlimited Update, Dec 3rd 2022

In our Roasting Science course this week, we dig into the difference between heat and temperature, and how this difference underlies the concept of specific heat capacity.

The distinction between heat and temperature explains many important phenomena in roasting. For example, the importance of the between-batch protocol rests on the idea that charging at the same temperature is not the same as charging with the same amount of heat. The concept of heat capacity also explains why coffee roasts faster in humid air, and why drum roasters respond more slowly to changes in the gas settings than fluid-bed roasters do.

Thermal energy is the kinetic energy of atoms moving within a substance, whether that's individual molecules moving around in a gas (a), atoms vibrating in a solid (b), or atoms shifting their position within a molecule (c).

We also take a look at how well beans conduct heat. Surprisingly, heat transfer from the surface of the bean to the core appears to be relatively fast, so in all but the fastest roasts the core temperature is very close to the surface temperature for most of the roasting time. This has some interesting implications for how we think about development during the roast.

This new coursework requires a BH Unlimited Subscription — if you don't have one yet, you can start a risk-free two-week trial by following this link.

The Coffee Buyer's Guide to Colombia

Next in our Buyer's Guide to Colombia, we wrap up our chapter on coffee growing and processing, beginning with an overview of the inventive and innovative methods that Colombian producers have come up with for processing coffee.

Colombian producers are at the forefront of the current wave of interest in new processing methods and crazy intense fermentations. We take a look at the reasons why, and how the climate and even the terrain influence the processing methods that producers tend to choose.

Carolina Ramírez on her farm, San Antonio de la Piedra

We then interview Carolina Ramírez, the owner of San Antonio de la Piedra, to find out what processing looks like on a typical, mid size farm in Colombia. Away from the spotlight, and lacking the capital to make big investments in infrastructure and marketing, most producers rely on traditional methods to grow and process their coffee.

Carolina explains some of the challenges she faces on her farm, and the limitations of new harvesting techniques and experimental processing methods in keeping a farm like hers on a sustainable footing.

BH Unlimited subscribers have advanced access to each new lesson as the course progresses.

The Espresso Vanishes: Part 3

The third instalment of The Espresso Vanishes went live today. It's a 4-part series by Sebastien Delprat. If you missed Part 2, here's a link to Back to the Roots. There's something distinctly Agatha Christie-like about this instalment. Picture yourself gliding up the Nile by paddle steamer, or gliding by night past the Moka Lighthouse with Robert Ulrich Etzensberger as your enigmatic travel guide.

Advertisements for the Midland Grand Hotel, from Bradshaw's Notes for Travellers (1884)

It's no surprise that steam-boat was the preferred mode of transport for an inventor whose life's work was devoted to bringing steam-powered coffee makers to the luxurious hotels of Europe. In addition to drawing up patents for coffee makers, Etzensberger also managed hotels in Italy, Switzerland, and London — including a position at the colossal Midland Hotel at St. Pancras in London (above). Ten years before Moriondo and thirty ahead of Bezzera or Pavoni, Etzensberger — a Swiss-German — was harnessing steam power to deliver a new coffee culture to Europe. He also released a patent in 1880 that shows a 'coffee box' that could very nearly be considered a portafilter, over 20 years ahead of Bezzera.

The last patent from Robert Ezensberger (from the US, 1880) shows his 'coffee box' attached to the steam-pressured water tap by a special fitting, making it a precursor system to the espresso machine portafilter.

To find out more about an inventor who was also very possibly Europe's most well-travelled individual in the 19th Century, head here to read The Moka Lighthouse … free to read for this weekend only.

An Ad-Free Learning Experience

At BH we never do ads for other company's products on our website. There's no product placement in any of our courses, newsletters or blog posts. Our only income comes from what you pay for your subscriptions. When you see machinery or coffee gear mentioned in any of our educational material, or featured in our course videos, we have chosen to use that equipment because we like using it, because we think it's historically significant in the evolution of the espresso machine, or because it shows you something you need to see about modern coffee culture. It's as simple as that.