Friday, March 17, 2023

Iced Latte Art - Mar 17th 2023

Iced Latte Art

BH Unlimited Update, Mar 17th 2023

Remember when latte art was a sure-fire way to separate specialty cafes that knew what they were doing from the pretenders? In the decade or two since, some of the big chains have caught up and even overtaken specialty cafes in some ways — for example, by creating 'cold foam' to bring a more luxurious texture to the ever-popular iced latte.

Popular as it is, from a visual standpoint, cold foam is a throwback to the tall, foamy lattes of the 1980s. But it recently made a minor breakthrough that could put specialty coffee shops ahead of the chain stores once more — we successfully poured latte art in an iced latte. It turns out that if you have the right milk, the right equipment, and a bit of patience, it is indeed possible to pour (simple) latte art with cold milk foam.

A latte foamed and poured by Lloyd Meadows using the Nanofoamer with warm milk at ~55°C

This post is the first of three that will explore cold milk foam and how to optimise it — and along the way, we will shed some light on how milk foams, and explode some myths about milk steaming which, until now, we have been accepting as an established fact.

Roasting Science

Do you know the Froude number of your roaster? Choosing the right drum speed is a vitally important part of tuning up your roaster to get the best out of it, but is frequently overlooked — not just by roasters, but by manufacturers too. You might already know that the optimal drum speed depends on the size of your roaster: Larger roasting machines generally need to turn at a lower rpm to achieve similar results.

The Froude number is a way of describing drum speed that is independent of the size of the drum. Armed with the Froude number, you can calculate the optimal range of rpm for any size of roaster.

The mathematics involved in calculating the Froude number are a little bit fiddly — but in this week's lessons, we give you a handy app to calculate the Froude number for yourself. Whether you're tuning up a new roaster, or checking the settings on your current machine, knowing the Froude number gives you a clear starting point for finding the ideal drum speed for your roaster.

Simply provide the inner diameter of your drum (in centimetres) and the rpm you are using, and the app will show you the Froude number of your roaster. Alternatively, provide the Froude number you wish to target, and the app will show you the rpm you need to reach that number.

In these lessons, we also explain in detail exactly why drum speed is so important. We show you how the drum speed affects the way beans flow within the roaster, and explore how that affects the balance of conductive and convective heat transfer to the beans.

Coffee Buyer's Guide to Colombia

This week in our guide to Colombian coffee we begin our exploration of the social and economic factors related to coffee production in Colombia.

We start by looking at the development of traceability in Colombian coffee. The FNC's pioneering promotional campaign established Colombia as one of the first recognisable 'single origin' coffees — but this may paradoxically have held back the recognition of Colombia's individual growing regions as distinct origins.

The FNC first registered '100% Café de Colombia' as a trademark in the 1950s, and the federation has informed how Colombian coffee has been marketed ever since.

Some of the growing regions that are most important to specialty coffee buyers today only emerged as distinct origins within the last few decades, as Colombia underwent a dramatic shift in coffee production. We discuss the causes and consequences of that shift, and how that led to changes in the role of women in Colombian coffee production.

Finally, we discuss the economic effects that leaf rust, fluctuating coffee prices, and climate variability have had for producers in Colombia, and the future challenges that growers face.

Coffee Education — Without the Advertising

BH provides a level of detail about coffee production that platforms like Youtube are unable to obtain, because we are a subscription service — our members pay us to produce the best, most detailed information for them, rather than creating videos that get the most views for an advertiser.

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.