Everything You Need to Know about Coffee Grinds

When we think of making coffee, we usually focus on getting great coffee beans. But to have truly amazing coffee you, need right coffee grind for the right brew.

The science of coffee grinds is part math, part chemistry, and all about taste. In this post, we’re going to break down the types of coffee grinds and what brew methods they work best with. Let’s get going.

THE MATH 

The biggest reason coffee grind size matters is because it changes the surface area of the coffee itself. A single coffee bean has a small surface area, and even if you put a handful of beans into water, only a small percent of the water would come into contact with the beans, and you definitely wouldn’t call the result “coffee.” So when you grind the beans, you’re creating more coffee surface for the water to contact.

Surface area of the coffee beans – meaning the grind level – and the contact time the water has with the coffee change the taste of the coffee. For instance, a coarser grind is better for brewing methods that take more time. Cold brew, french press, and aeropress all need coarser grinds. pourover only gets a short time for the water to contact the coffee, so it needs a finer grind.

THE CHEMISTRY 

Here’s a question: do you know what actually makes coffee, coffee? After it’s brewed, what is left of the coffee beans in the water? The answer: coffee compounds! There are hundreds of compounds in roasted coffee beans, and when you brew coffee, you’re transferring those compounds into the water to make a delicious drink. If you want to know more about these compounds, you can read up on more coffee science.

The right grind for the brewing method produces a good transferral of these compounds into the water. Too large a grind for the brew type and you’ll get weak coffee, because not enough of the compounds will be transferred. Too fine a grind for the brew type and you’ll get much stronger coffee (not that we’d complain).

SHOULD YOU BUY PRE-GROUND COFFEE? 

Many people buy pre-ground coffee, but is this has two disadvantages. The first is that you can’t control the grind size, and so you just have to make do with whatever grind size the company chooses.

The second disadvantage is that the coffee compounds are protected by the coffee bean in its unground form. And although the coffee bags are sealed, the grounds will lose their freshness faster than coffee beans themselves. It means you’ll spend an extra half minute or so whenever you make coffee, but it’ll be worth it in terms of coffee freshness and taste.

COFFEE GRINDS & BREW METHODS 

Now that you know why grind matters, here’s a chart of some popular brew methods and the optimal grind size for each method:

Once you’ve mastered coffee grinds, have fun experimenting with different brew methods. If you don’t have a grinder yet, check out our post about coffee grinders and the other coffee gear essentials you need.

Enjoy your fresh-ground coffee!