I often use coffee specific jargon in my writings here, so I’d like to lay out what everything means in the context I’ll be using it in for those who are not familiar. As well as coffee jargon, I’ll also include any scientific terms in the context in which I use them. If you find yourself wondering what something else means, please do ask and I’ll do my best to explain it for you! I’ll try to keep this page updated whenever I use a new term on a post.

I’ve broken it up into coffee terms, experimental terms, how I describe grind setting, and people I’ve referenced. That way you can just read the sections you’re not familiar with.

Coffee Glossary


Disturbances in the slurry during brewing. Can come from many sources, stirring, spinning, pouring, etc. Generally increases extraction.


How parallel and concentric the burrs in a grinder are. Big focus on parallel.


A phase in brewing where the grounds are allowed to rest after being wet with water. Also in espresso when the coffee is allowed to rest with no pressure after preinfusion.

Brew Mass / Beverage Weight

The weight of coffee or espresso in the cup at the end of brewing.

Brew Ratio / Ratio

The amount of coffee to the amount of water. Expressed as Coffee:Water, so 15:255 for a brew that starts with 15 grams of coffee and adds 255 grams of water. Almost always uses total water for the water weight, although uses beverage weight for espresso as the total water is unknown.


Water that ends up directly in the finished beverage without passing through coffee. Whether added intentionally or by getting through the walls of the filter.


Water taking shortcuts through the coffee, leaving some areas less extracted than others.

Dry Weight / Dose

The amount of ground coffee used for the brew.


A very strong type of coffee brewed in an espresso machine. Not a type of beans or roast level, and I will never use it as such.


The process through which soluble compounds in coffee are pulled from the dry coffee into the water to make the coffee beverage.

I do not use this term to refer to the moving of undissolved stuff like sediment leaving the coffee bed. It’s not wrong in a dictionary sense, but it creates a lot of confusion in extraction yield.

Extraction Yield / Exty

The amount of the coffee that was extracted and ended up in your cup. Expressed as a percent derived from the equation \(Exty = \frac{TDS*Brew Mass}{Dose}\).

Extraction yield is only based on soluble content, sediment and oils are not included.

Liquid Retained Ratio / LRR

The amount of water held back in the coffee after brewing.

Oils / Lipids

Simply oils from coffee. I’ll mostly be using it to refer to oils that made it to the cup. Mostly get these with methods not using a paper filter.

Particle Distribution / PSD

Data, usually presented as a graph, showing what size grinds a grinder makes at a given setting.


Stands for proportional–integral–derivative. Basically it uses live feedback to keep a thing at the set value. Will most often mean an espresso machine or kettle using this technology to keep temperature constant, but also applies to the way my EG-1 keeps RPM constant.


Parts per million. Used to indicate the mineral content of water.


A phase in espresso brewing in which lower pressure than brew pressure is used to saturate the puck.

Rao Spin / Spin

Spinning the slurry of a brewer to minimize channeling. Not actually invented by Scott Rao, but he does approve of it.


An instrument used to determine the TDS of coffee.


The amount of coffee stuck in the grinder after grinding.

Reverse Osmosis / RO

A method of filtering water to high purity, about 10ppm. I use this as a base for mixing my brew water as well as rinsing glasses to prevent clouding.

Ross Droplet Technique / RDT

A method in which a spritz of water or droplets of water are applied to coffee beans before grinding to keep static down. First proposed by David Ross in a 2005 Alt.Coffee post.

Sediment / Suspended Solids

Dry coffee that ends up in the cup. I typically use sediment to mean any dry coffee and suspended solids for the most microscopic sediment.


The mix of coffee and water.


The concentration of a brew. I like to give this in TDS as I feel brew ratio is a poor way to express strength.


The amount of the coffee or espresso that isn’t water. Usually expressed as a percentage.

Total Water

The amount of water added during brewing.


The variety or cultivar of a coffee. Basically what breed of coffee it is.


Voice Systems Technology, Inc., primarily known for their coffee refractometers, syringe filters, and precision portafilter baskets. I find myself referring to all three just by VST depending on context, so sorry about that.

Weiss Distribution Technique / WDT

A method in which the grounds in a portafilter basket are stirred to homogenize them before pulling a shot. It appears Mark Podolsky was the first to call this method WDT.

Experiment Glossary


How close a measurement is to the real value. Or another number assigned to act as the real value. See diagram.


The internal consistency between two measurements with the same method. See diagram.

Systematic difference

The median difference from the reading against which it’s compared.

EG-1 Grind Description

Grind Size

Each large number is a whole number. Each number has ten notches in the middle, making for .1 increment notches and .5 halfway points.. I use 0 to be the closest point the burrs get to each other while reading 0. Going finer than this point I use negative numbers (e.g. -1.2). Going coarser is positive numbers (e.g. +6). On the rare occasion I need to go coarser than +9, I will use a revolutions prefix (e.g. 1R+2).

-3 is the closest I can get the burrs with the burrs currently in the grinder. Each notch (remember, ten notches per number) on the grinder going up from there represents 5 microns of added space between the burrs.


RPM corresponds to the speed at which the burrs are set to spin on the EG-1.


This is a list of people that I have referenced the works of at some point. This list is not a list of all the big names of coffee, it is not a list of only big names in coffee, it is not a list of people I feel are most relevant to coffee, or of any personal favorites. Just of people I have at some point referenced on this site so that readers know who I’m talking about.

I’ll try to be sure everyone I reference ends up on here provided they have a site to link to. Names are all links to the individual’s page and listed in alphabetical order by last name.

If you are on here and want your description changed or your link to go somewhere else, or want your name removed, let me know and I’ll make it happen.

Jonathan Gagné

Astrophysicist and coffee geek at Coffee Ad Astra, Coffee Brewing with a Scientific Focus

Referenced in Comparison of Espresso Filtration Methods, Universal Extraction Calculator,Measuring Extraction in Coffee and Espresso

Matt Perger

Founder of BaristaHustle

Referenced in Sandpaper Alignment Guide

Scott Rao

Coffee consultant and author

Referenced in Sandpaper Alignment Guide, Measuring Extraction in Coffee and Espresso