Grind Size – Why it matters
Hi everyone – this is Ron Kelley. I am a guest blogger for Arnold’s Coffee. In this article we want to introduce you to the first of four key factors in making a great cup or mug of coffee - that factor is the Grind Size. Why is grind size important? We believe your journey to a great cup of coffee starts with the right grind. The grind selected and consistency of that grind can be the difference between the best cup of coffee you’ve ever had and a cup that’s bitter and undrinkable.
There are three important factors which make the biggest difference in choosing the correct grind size: extraction rate, contact time and flow rate. To elaborate a bit:
The larger the surface area of your ground coffee exposed to the brewing process, the greater the extraction rate.
If you grind the coffee finer, the surface area increases along with contact time.
Less contact time is required as the extraction rate increases.
A fine grind will reduce the flow rate of water and increase the contact time.
What does this tell us?
It means that if you use a brew method with a short contact time, such as espresso, the grind should be finer. But for an immersion brewer which steeps the coffee grounds in water for several minutes, the contact time is much higher. Therefore, immersion brewing requires a coarser grind than most other brew methods.
If the contact time is too high or the grind is too fine for your brewing method, it will produce an over-extracted brew which can be bitter. If the grind is too coarse or the contact time is too short, the coffee will turn out weak.
A proper balance between grind and contact time is required to produce the best result.
So, which grind size should you use?
Simply put, the brewing method you use will dictate the grind size required to produce the best possible cup.
Espresso is brewed using pressure to force water through compacted coffee grounds. The contact time is very short, requiring an extra fine grind size.
The French press is an immersion brewer. Water is added to coffee grounds and allowed to steep for several minutes before straining out the grounds. This method calls for a coarse grind setting.
If you use an AeroPress, a popular single-cup manual coffee maker similar to a French press, a grind size is between medium and fine, depending on steeping time, works well.
Pour-over brewers, like a Chemex, come in a wide variety of shapes and sizes. Most pour over methods work best with a medium to medium-fine grind.
Drip coffee is what you typically get at coffee shops or often brew in 8-12 cup brewers at home. Contact time is regulated by a small hole in the bottom of the brewing basket, so recommended grind size varies between medium-coarse to medium.
Cold Brew is becoming popular and is done at or below room temperature requiring 12 to 72 hours to process. Because of the low temperature, extraction rate is low, no matter what the grind size. To make it easy to filter, use a coarse or extra coarse grind size. A finer grind size will work and shorten the steep time, however it may cause the final product to appear cloudy.
I think you will can see why we say coffee must be ground properly for the type of brewing you will use to maximize your coffee drinking enjoyment.
At Arnold’s Coffee, we offer several different grinds, including Whole Bean, which we recommend for maximum coffee freshness by grinding your own at home. We also offer quality grinders that give you precise control over grind size and consistency. Or if you prefer, we will provide your Arnold’s Coffee ground as Fine, Drip or Coarse (French Press) and packaged in our high quality, multi-layered foil composite bags that ensures a fresh arrival.
In our next article, we will consider the importance of Temperature
Please feel free to contact us with your suggestions and comments.
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