Temperature’s Hidden Effect

Temperature’s Hidden Effect

In our most recent instalment of the Advanced Espresso course, we discussed a surprising finding in the scientific literature: that increasing the brew temperature makes espresso shots run more slowly. We set out to test this for ourselves, and discovered that the truth is more subtle …

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Coffee Grinder RPM

Coffee Grinder RPM

In the last few years, a small number of grinders have hit the market that boast an adjustable grinding speed. The best known of these are Lynn Weber’s EG-1, Victoria Arduino’s Mythos 2, and most recently Ceado’s Hero E37Z. The marketing material for each of these grinders claims that being able …

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Changing Grinder Burrs

Changing Grinder Burrs

If you’re looking at your grinder, asking yourself this question, then it’s probably time to change them. While grinder manufacturers may claim that their burrs can grind hundreds and sometimes thousands of kilos of coffee, the truth is that, after they are seasoned, burrs wear out gradually over time …

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Cinnamongate

Cinnamongate

“It tastes exactly like a cinnamon bun. You have to try it.” Coffees often don’t entirely live up to their description, but this was different — a coffee with an instantly recognisable flavour of warm, sweet, cinnamon, like nothing I’d tasted before. I had joined the small crowd queuing up …

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Why Do Espresso Shots Run Faster?

Why Do Espresso Shots Run Faster?

Why do espresso shots run faster when I use super fresh coffee? It is a truth universally acknowledged that the gases trapped in fresh coffee create bubbles in espresso, which slows down the flow and reduces extraction. This explains why shots from older coffee run...

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If a Coffee Doesn’t Form a Crust In a Cupping…

If a Coffee Doesn’t Form a Crust In a Cupping…

Does this mean it’s underdeveloped? Anyone who’s cupped very light roasted coffee, whether from a Nordic-style roaster, or perhaps from a sample roast, will have experienced this: it sometimes doesn’t form a crust in a cupping. When this happens on the cupping table,...

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Sugars in Natural Processing

Sugars in Natural Processing

In natural processing, do sugars travel from the mucilage into the bean? Natural processed coffees are typically sweeter and more full-bodied than washed coffees, and often have distinctive fruity flavours. It seems intuitive that the sweetness, body, and...

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Fluidised Beds

Fluidised Beds

In our latest poll on the BH Facebook Group, you asked us to check this out: 'If flow goes in much faster than it comes out, then you have the potential to create a fluidised bed. Where does that leave espresso?' Here's what we found out ... This question follows on...

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Steel, Glass, Ceramic?

Steel, Glass, Ceramic?

What's the most temperature-stable material to use when brewing? The short answer is: plastic cones are best. They absorb heat from the brew water less quickly, absorb less heat overall, and lose that heat to the air more slowly. To really understand why plastic is...

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What’s the Best Sprayhead Design?

What’s the Best Sprayhead Design?

Is it better to have as many holes as possible in your spray head, hardly any to make more agitation, or somewhere in between? To achieve even extraction in batch brewing, it’s important to get all the grounds evenly wetted — meaning exposed to the same amount of...

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If Not Channelling, Then What?

If Not Channelling, Then What?

"Professor Abbott told us he doesn’t really believe channelling occurs in espresso (except in drastic cases). So if not channelling, then what?" Only a few weeks ago we were telling you that over-extraction isn’t really a thing, and that it’s all caused by...

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Fines Migration

Fines Migration

You asked us to look into this topic, “In espresso, fines migration may not be as much of a thing as we thought.” Here’s what we found.  Fines are the smallest particles created when you grind coffee. Depending on who you’re talking to, they might be defined as any...

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Is It Better to Sieve Out Particles Smaller Than 400μm?

Is It Better to Sieve Out Particles Smaller Than 400μm?

Or is it better just to leave them in, when brewing filter coffee? Back in 2012, our very own Matt Perger won the World Brewers Cup, using a 250μm sieve to remove fines. This created a more even extraction, which allowed him to extract higher without getting dry and...

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Espresso With Aeropress Filter Papers

Espresso With Aeropress Filter Papers

Above and below the coffee bed This week, Scott Rao made espresso with filter papers above and below the coffee bed yielding over 25%. What's he playing at? If you follow Scott Rao’s series of daily coffee tips on Instagram, you’ll have seen one recent post where he...

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What Difference Will It Make to an Espresso

What Difference Will It Make to an Espresso

Decades of trial and error have shown that most people prefer espresso extracted between 85-95°C (A Illy and R Viana, 1995). For lighter roasted, special coffee, the range typically used is rather narrower – 90-95°C. Within that small range though, there are still considerable variations in flavor to explore.

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Can You Please Summarise Cafe Imports’ Water Activity Paper   In our bi-weekly poll on the BH Facebook-group you asked us, "Can you please summarise this impressive research paper", which is based on a huge amount of cupping and data logging by influential green...

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How to Read Chemical Equations

How to Read Chemical Equations

Any time you’re reading about chemistry, you’re going to come across chemical formulae and equations. You might well remember these from high school chemistry, but if it feels like a distant memory then this refresher might be useful. This post goes out to the BH Unlimited subscribers attempting the first instalment of The Water Course.

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What Is the Maillard Reaction and Why Is It Important?

What Is the Maillard Reaction and Why Is It Important?

The Maillard ‘reaction’ is actually a whole series of chemical reactions that are crucial to creating the characteristic flavours and brown colour of roasted coffee and many other foods – including chocolate, toast, and grilled steak. The reactions are named after Louis Camille Maillard, a French doctor who first described them in 1910.

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