Flavor Extraction Differences: Coffee Grind Size for Various Brewing Methods | How Coffee Grinding Affects Flavor

After roasting, the cellular structure of coffee beans is disrupted, becoming relatively loose, but the cell walls are filled with carbon dioxide, oils, and aromatic flavor compounds produced by pyrolysis. The bean body itself expands as a result. However, if whole roasted beans are brewed directly with hot water without grinding, it's difficult to release the aroma and water-soluble flavor compounds stored within the cell walls, making it challenging to brew delicious coffee. To unlock the coffee's flavor, coffee beans must be ground into powder before brewing. Only through grinding and crushing can the hard cell walls be broken open, allowing hot water to enter and extract the coffee.

How you grind your coffee (and when you grind) is the first step toward affecting the final brew taste. Believe it or not, you can have the highest quality coffee, perfect roasting, pure water, excellent filters, and outstanding coffee machines, but still ruin everything due to incorrect grinding. But don't let this dilemma stop you; some basic knowledge about coffee grinding will greatly help you make perfect coffee.

The Importance of Grinding

Regardless of your coffee brewing method, the fundamental goal of grinding coffee beans is the same: to break down the roasted coffee beans and expose their interiors to extract flavor. Ground coffee has a much larger surface area than whole beans, allowing water (the extracting agent) to contact more coffee during brewing. More contact means more flavor extraction and better yield. However, this must be done under conditions suitable for the coffee beans. For example, FrontStreet Coffee typically uses a grinding setting of 11 on the EK43S for Mandheling coffee, because Mandheling coffee itself has a very rich flavor. If fine grinding were used, the entire coffee would become even more bitter. Coffee beans from Africa often use slightly finer grinding settings~ For instance, for the common Yirgacheffe coffee, FrontStreet Coffee typically uses a grinding setting of 9.5 on the EK43S to better highlight its floral notes and fruity acidity, preserving the original flavors within the coffee beans.

The Importance of Grind Size

The size of coffee grind is extremely important. Regardless of the brewing method you adopt, coffee making involves extracting flavor (and caffeine) from coffee grounds. The finer the coffee beans are ground, the larger the exposed surface area of the grounds, and the faster the extraction speed. This is why coffee for espresso machines is ground finely, because water in espresso machines passes through the coffee powder very quickly under high pressure. On the other hand, cold brew coffee is made with coarse ground coffee, because this cold extraction method allows coffee to stay in contact with water for longer (several hours, compared to 30 seconds for espresso).

Please note~

After coffee beans are ground into powder, their surface area increases, and their contact with air becomes wider, leading to rapid oxidation. Volatile components in ground coffee powder gradually blend into the air and lose their aroma. Therefore, the best time to grind is just before brewing coffee.

If you have a coffee grinder at home, you can try different grinding methods to find the one that suits you best. Before that, FrontStreet Coffee would like to introduce four relatively standard coffee grind sizes for your reference~

Standard Grind Sizes

Extra Fine Grind

Particle Size: Like MSG

Suitable Brewing Equipment: Espresso Machine

Fine Grind

Particle Size: Like MSG and sugar

Suitable Brewing Equipment: Moka Pot, Espresso Machine

Medium Grind

Particle Size: Like pepper and sugar

Suitable Brewing Equipment: Drip Coffee Maker, Pour-over, Siphon

Coarse Grind

Particle Size: Like sesame seeds

Suitable Brewing Equipment: French Press, Cold Drip Brewer

Factors Affecting Coffee Flavor

FrontStreet Coffee believes there are roughly three factors that affect a cup of coffee:

Grind Size: The finer the grind, the more intense the coffee; the coarser the grind, the lighter the coffee flavor.

Brewing Time: The longer the brewing time, the more intense; the shorter the time, the lighter.

Water Temperature: The higher the water temperature, the more intense the coffee; the lower, the lighter.

If your coffee tastes sour and thin, your beans might be ground too coarsely. Try a finer grind to see if it solves the problem. If your coffee tastes overly bitter, you might be grinding too finely. A coarser grind might improve your brewing results. (Brewing time and temperature also affect flavor.)

So why is fineness so important? Because it directly affects extraction rate and coffee concentration. Different beans have their most suitable fineness. Besides multiple experiments, it's recommended to refer to the perfect extraction rate range (18%-22%) and optimal concentration (1.15%-1.55%) from Golden Cup Theory. As long as you make fine adjustments within this range, you won't cause the coffee's flavor to change too much or result in poor flavor profiles. For beginners, this also makes it easier to brew good coffee. Why not take time to familiarize yourself with the most suitable fineness for each bean? After all, a difference of 0.5 on the scale can create different flavors!

Professional coffee knowledge exchange and more coffee bean information, please follow Coffee Workshop (WeChat public account: cafe_style)

For more specialty coffee beans, please add the private WeChat of FrontStreet Coffee (FrontStreet Coffee), WeChat ID: kaixinguoguo0925

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473