Why Grind Size Matters...The Science of Extraction

Have you ever wondered why the flavor of your coffee can vary wildly depending on the day and type of brewing mechanism used? If you have, you would not be alone! Many (including myself at one time) do not understand the science behind a great cup of coffee.

In case the word “science” is making you sweat and you are tempted to click out of this link...please hold tight and continue reading, the science just is not that complicated. There is a method to the madness...I promise.

So, here we go...why grind size matters.

Coffee brewing is a chemical extraction process, which means that hot water dissolves the soluble compounds in the coffee. The compounds found in coffee can be broken down into three basic categories:

·      Acids (bright, fruit notes—extracted first)

·      Sugars (sweet, smooth notes—extracted second)

·      Bitters (dry, harsh compounds—extracted last)

Grind size controls the surface area and flow rate, which determines how much and how fast each of the compounds are extracted.

Grind Size=Control of Flavor

·      Too course=under-extraction, meaning the water flows through too quickly. This produces a sour, weak or hollow flavor profile.

·      Too fine=over-extraction, meaning the water flows through too slowly. This produces a bitter, dry or astringent profile.

·      Just right = balanced, sweet and complex. It provides a delightful cup of joe.

If you’d like to know which grind is generally good for various brewing methods, check out our downloadable chart for brewing. While you’re there, feel free to pick a free template that documents your brewing experiments so that you can more easily identify the perfect combo for you!

How to Grind Properly: Step-by-Step

1.        Use a Burr Grinder (Not Blade)

·      Burr grinders crush the beans uniformly.

·      Blade grinders chop unevenly, which mean there is an uneven extraction...no bueno.

·      Recommended home grinders: Baratza Encore (manual brew), Eureka Mignon (espresso) or the Fellow Ode (precision).

2.        Grind Just Before Brewing

·      Ground coffee oxidizes SUPER FAST, losing its aroma and flavor very quickly.

·      Whole beans stay fresh much longer...this is a way to protect your precious elixir longer.

3.        Weigh Your Dose (Not Scoop)

·      Seriously, this is not just a purist’s ideology at play...it matters!

·      Use a scale—we like Fellow’s Tally scale for accuracy. Precision=consistency. It really makes a difference.

·      1:16 ratio is a great start (e.g., 20g to 320g water).

4.        Dial in the Grind

·      Use the taste-adjust-taste method:

·      If the brew is sour, salty, flowing too quickly---grind a bit finer

·      If the brew is bitter, dry, flowing too slowly---grind a bit coarser

·      Take care to adjust in small increments (1 notch or 1-2 seconds of grind time)

Want a deeper dive into other factors that will impact the quality of your coffee?  Reach out and set a consultation appointment! We would love to nerd out over coffee with you and help you dial in your brew to your own preferences.

In the meantime, want some free resources on us and to begin exploring & dialing in your brew like a pro? Just click on the link below...Happy Brewing!

Coffee Grind Extraction Education