By James Gallagher for Steampunk Coffee
I have been thinking about what words I use the most when it comes to pour-over brewing and I thought it would be useful to put together a little glossary. If you hear someone say a word you do not understand, or if you read a word you've never seen before, I hope this glossary can be some use. I've decided to focus solely on pour-over brewing, which is a type of percolation brew. This is because every brew method (i.e. pour-over and espresso) has their own language.
Over the last few months, I have learned how to read a coffee recipe and understand what changes I can make to my brew. I built up my knowledge by reading books, blogs (like this one!) and watching videos to see what other people do to make their brews. When I write about coffee brewing, I find that I depend on the very same words that at one point I knew little about. This is the result of learning.
Percolation
Percolation is any brew where water falls through a bed of grounds into a decanter below. The water from your coffee is pulled through the bed of grounds by the force of gravity. Percolation brewing is not to be confused with the percolator, a machine associated with the production of bad coffee.
Unlike brewing with, say, a French press or an Aeropress, percolation brews are constantly topped up with water. This is done by using one of two pouring techniques: pulsing and a continuous pour.
Pulsing
A pulse is a particular amount of water you pour over your grounds of coffee. Most pour-over recipes call for three or more pulses. Pulses include the "blooming" phase, where you add a small amount of water to your grounds to make sure they are all wet before brewing. My Kalita Wave recipe calls for five pulses in 50 gram increments.
With the exception of the bloom, pulses are almost always the same weight. This is because you want your slurry to maintain a consistent height. This helps the water extract delicious flavours from the coffee. If your pulses were inconsistent, your slurry may be too high or too low at different points of the brew.
Bloom
The blooming phase is the first part of pour-over brewing. Blooming involves pouring a small amount of water over your bed of grounds. This stage helps to ensure all the coffee is covered in water before the rest of the brewing process continues. If some coffee is not saturated with water, it will release flavours at a different rate than the rest of your brew.
A bloom typically lasts 30 or so seconds and may involve some amount of agitation. If you're using fresh coffee, you should notice some bubbles rise to the top of your slurry. This indicates that carbon dioxide is leaving the coffee. The fresher your coffee, the more carbon dioxide will be present in the grounds.
Dilution
This phase is when you add the rest of the water with which you intend to brew. You can add water using either a pulsing or a continuous pouring technique. This phase is called "dilution" because you are adding more water to the grounds, thus diluting the strength of your solution.
Dilution may also refer to adding some water after brewing. This is done to reduce the strength of the brew. Diluting a brew in this way is not as common in pour-over brewing as it is in espresso and Aeropress brewing.
Drawdown
The final phase of brewing is called the draw down. During the draw down, the rest of the water from your coffee will flow through the bed of grounds and into your cup below. No more water is added during the draw down phase.
It is common to stop the draw down phase after a specified period of time. I usually stop my drawdown after three and a half minutes. This is because water usually slows its flow rate throughout pour-over brewing. It would take too long to let every last drip leave the coffee.
Slurry
The slurry is the mixture of coffee and water in your brewing device. If you ever hear "stir the slurry," for instance, someone is instructing you to stir the coffee and water with which you are brewing.
Gooseneck kettle
Most pour-over brewers use a gooseneck kettle. This is a special type of kettle with a spout that looks like a goose's neck. You may hear this type of kettle referred to as a swan-neck kettle, too. Gooseneck kettles often have a slightly curved end.
Gooseneck kettles give you more control over how quickly your water flows. This is important in pour-over brewing because you need to pour certain amounts of water in each pulse. If you cannot control how quickly your water flows, you will find it difficult to meet your pulse targets. Also, gooseneck kettles give you more control over the direction of your water flow. This will help you make sure you pour where you want to pour (i.e. in the centre of the brewer or around the edges).
Filter
Filters separate your brewing device from the slurry. Home brewers use filters to make sure that no coffee grounds make their way into the final brew. The most common material for pour-over filters is paper. Paper filters are very effective at keeping coffee grounds out of your final brew. You can also get metal and cloth filters for pour-over brewing. But, these filters require a lot of maintenance and a strong technique to use effectively.
Coffee Bed
No, your coffee does not fall asleep. The coffee bed is the layer of grounds in your brewing device. Your coffee bed is dry at the start of the brewing process, before you add any water, and is wet at the end.
A flat coffee bed at the end of your brew tells you that your coffee is more likely to be extracted evenly. This is because water follows the path of least resistance. If your bed is on a slope, the water will have flowed to the shallow end of the slope and spent less time in contact with the other grounds in your coffee bed.
Preheating and prewetting
Before you put your ground coffee into your brewing device, you should preheat or prewet your filter, your carafe (if you are using one), and your mug. To preheat your filter, carafe, and mug, pour some water in each device. If you are preheating a Kalita Wave filter, make sure that you pour in the centre of the filter. This will reduce the chance the filter collapses and loses its structure.
Prewetting your filter helps to take out any paper taste in the filter. I have never had a brew that had a clear paper taste even without prewetting the filter but this may be down to the type of filter I use (Kalita Wave filters). Prewetting your filter will also heat up your brewing device. The hotter your device, the warmer your slurry will stay during brewing. A warmer slurry helps with even extraction.
The last thing you want is for your coffee to cool down too much before it has even brewed. To keep your coffee warm during and after brewing, you should preheat any device into which you will decant your coffee. This applies to mugs, carafes, and flasks. If you do not preheat your brewing vessel, the vessel will take some heat away from your brew.
Brewing Device
I use the term "brewing device" when I talk about pour-over objects because there are so many. It would be unfair for me to always refer to the Kalita Wave because it is only one of many methods of making a pour-over coffee. You may see V60s, batch brewers (coffee makers capable of brewing large batches), Origami drippers, Mellita drippers, Beehouse drippers, and more pour-over devices. I cannot keep track of them all.
I could go on and on about various words used in pour-over brewing. As I learn, I will probably discover more words that relate to pour-over. In this article, I have aimed to give you a taste of some words you will commonly see in recipes and conversations about pour-over brewing. Ultimately, you do not need to know every coffee brewing term to brew a delicious cup. But, knowing some words will help you describe what you do, search for solutions when you are stuck, and better understand what you read and hear.
Contributed by James Gallagher, a home brewer and coffee enthusiast. View his excellent blog at jamesg.blog