Coffee Bean Grind Size Standard: How Fine Should Pour-Over Coffee Be to Avoid Over-Extraction

FrontStreet Coffee - Guide to Pour-Over Coffee Grind Size

Grind coarseness is one of the factors affecting pour-over coffee extraction. Grind size refers to the size of coffee particles. Simply put, the size of coffee particles affects the contact time between coffee and water.

Grind Coarseness → Contact Surface Area, Extraction Speed

Grind Size

Fine grinding allows hot water to extract more substances in the same amount of time. However, if ground too finely, it may extract too many substances, making it prone to over-extraction.

If you choose coarse grinding, hot water will extract fewer substances in the same time. Conversely, if ground too coarsely, it may extract too few substances, leading to under-extraction.

Coffee Extraction

The order of substances extracted during coffee brewing is: acidity, sweetness, bitterness, and finally astringency.

Different coffee grinders produce different grinding results, even if they are the same brand and model.

Different types of burr blades produce different shapes of coffee particles. Different shapes result in different coffee extraction effects.

(Some are flaky, some are chunky, some are more rounded)

Different coffee grinders have different distributions of particle sizes. Different distributions of coarseness and fineness lead to different coffee extraction effects.

(Some have a higher ratio of fine particles, others have fewer)

Recommendation

When discussing grind size with others, it's best not to mention specific grind settings but rather describe the texture you feel. For example: like flour, like salt, like coarse salt, fine granulated sugar, sugar, coarse sugar...

Coffee beans with different roast levels will produce different grinding results even on the same grinder setting.

At the same setting, darker roasted coffee beans will grind into finer particles. This is because darker roasted coffee beans have lower moisture content and are more brittle.

(If you pay attention, you'll notice: when using an electric grinder, the sound is different when grinding beans with different roast levels; if you use a hand grinder, you'll find: grinding light-roasted beans makes your hand more sore)

Recommendation

When you get a new coffee bean, test grind it before brewing to find the particle size you want.

What Are You Changing When You Adjust the Grind?

Sometimes, you might see someone put a roasted coffee bean in their mouth, chew it, and swallow it.

In this case, the teeth play the role of the grinder, while saliva acts like water, though at a slightly lower temperature.

Our sense of taste only works on liquid substances. Without liquid involvement, it's impossible to taste the flavor of solid coffee beans. If you say, "I licked the surface of a coffee bean and it has flavor," my answer is, "Because you have saliva on your tongue."

After coffee beans are roasted, their internal structure becomes honeycomb-like. Soluble substances adhere to the cell walls. Only by breaking them open and allowing them to contact water can these soluble substances dissolve in the water. Only then can we taste the coffee's flavor.

Key Point

When using the same water, time is the key factor for adjusting the types and amounts of substances extracted.

FrontStreet Coffee's Mission

In short: FrontStreet Coffee is a coffee research center dedicated to sharing coffee knowledge with everyone. We share without reservation, hoping more friends will fall in love with coffee. Each month, we hold three coffee promotional events with significant discounts because FrontStreet Coffee wants to provide the best coffee at the lowest prices to more friends. This has been FrontStreet Coffee's mission for the past six years!

Important Notice :

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