Saturday, October 22, 2022

BH Unlimited Update - Oct 22nd 2022

Cryodesiccation

BH Unlimited Update, Oct 22nd 2022.

Did anyone notice the trend for using modified milks in the milk-beverage course at the recent World Barista Championships? You could say that trend got started by Ben Put, who has won the Canadian Barista Championships let's just say many times, and finished third in the WBC on two occasions. In 2017 Ben introduced baristas around the world to the concept of freeze distillation — a method of concentrating milk to make it richer and sweeter. It sounds complicated, but to do it, you just freeze some milk and filter out the remaining ice as it thaws. Milk solids lower the freezing temperature of the milk so close to 0°C, only chunks of pure water remain frozen, while the rest of the milk, containing the milk solids, is liquid. The ice can then be filtered out, leaving a more concentrated milk behind.

Blocks of milk powder created by freeze-drying, as seen in this video showing the freeze-drying process

In Melbourne this year, WBC Champion Anthony Douglas stepped things up a notch with cryodesiccation. You can read all about Anthony's approach to his milk course in this new post on the BH Blog entitled What's the Deal with Cryodesiccation? The name sounds a bit Halloweenish, but really it's just a fancy word for freeze drying. Of course, the dried milk powder which you might remember from school camp is obviously disgusting. But that's because it's usually powdered skim milk, and it starts to taste pretty nasty after being stored for a while. By freeze-drying, Anthony was able to make freshly powdered milk that kept all the delicious flavour of the fresh milk he used for the competition. By applying gentle heat to frozen milk, while keeping it under a vacuum, freeze drying removes water, while keeping the composition and flavour intact. At low pressures, ice doesn't melt when it thaws — it skips the water stage and turns directly into water vapour. This process is called sublimation. The water vapour escapes, leaving the milk solids behind. Freeze-drying turns milk into a dry powder that can be reconstituted to make milk at any concentration you like. Anthony blended it back into fresh milk, to make a milk that was 1.8 times more concentrated than the original.

In addition to amping up the milk powder and texture, we're reliably informed that Anthony also used lactose-free milk as a base to blend the milk powder back into, If you haven't tried it, lactose-free is dramatically sweeter than untreated milk — almost too sweet. BH Unlimited subscribers can read about how to make lactose-free milk here in our Milk Science online course.

Roasting Science

In our Roasting Science course this week, we tackle a fundamental concept in chemistry that trips many people up: exothermic and endothermic reactions. Among other things, the chapter explains why …

- even if you have to apply heat to start a reaction, it can still be exothermic.
- beans absorbing heat in the roaster is not, by itself, an endothermic process.
- a spike in the rate of rise doesn't necessarily mean that the beans have become exothermic.

Caramelising sugar over a hot flame. The caramelisation reaction is endothermic.

We then investigate how important these reactions are during roasting, and their role in the 'plateau', 'crash' and 'flick' seen in so many roast curves. The answer is not as clear-cut as you might think — but understanding how the balance of exothermy and endothermy works goes some way to explain why the bean moisture content is so important in determining how a coffee roasts.

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

The Coffee Buyer's Guide to Colombia

This week in our Buyer's Guide to Colombia, we start a new chapter looking at how coffee in the country is grown, harvested, and processed.

We begin with some important background: explaining why coffee remains so important to Colombia's economy and identity, even as it makes up a smaller and smaller share of the country's exports. We also briefly look at the history and importance of the Federación Nacional de Cafeteros (FNC) — the extraordinary producers' organisation that controls the Colombian coffee industry.

The headquarters of the FNC in Cartagena, Bolivar

We then take a look at how coffee is grown in the country. Despite being such a large producer, Colombian coffee is dominated by very small farms, growing just a few hectares and processing their coffee on site. We look at how this production method came to be standard across the country, and how this history affects the way coffee is produced today.

New: My Education Hub

We've just launched our brand new online learning platform, making it far easier for users to navigate courses and lessons, while focussing all student activity and course progress on our new 'My Education Hub.'

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.