The Importance of Grind Size in Coffee: Why It Matters for Flavour and Brewing Perfection

In the world of specialty coffee, every detail counts, from the origin of the beans to the brewing method you choose. But there’s one factor that can make or break your cup: grind size. Whether you’re pulling a syrupy espresso shot or savouring a bright, balanced pour-over, the size of your coffee grounds plays a crucial role in flavour extraction, brew time, and overall taste quality.

In this guide, we’ll explore why grind size matters, how to match it to your brewing method, and how it impacts everything from aroma to mouthfeel.

If the grind is too coarse, the coffee may be under-extracted, resulting in a weak, sour, or watery cup.

In specialty coffee, consistency is king. Having the right grind size ensures balanced flavour and allows the unique tasting notes of the beans, whether fruity, floral, or nutty to shine through.

Understanding extraction is key to perfecting your coffee. Here’s the science:

• Coffee grounds have a specific surface area depending on how coarse or fine they are ground:
  • Finer grinds have more surface area, allowing water to extract flavours faster.
  • Coarser grinds have less surface area, requiring more time to extract the same amount of flavour.

Getting the grind size right is about matching surface area to brew time. For example:

• Espresso uses very fine grounds because the brew time is only 20–30 seconds.
• Cold brew uses coarse grounds because it steeps for 12–24 hours.

Each brewing method works best with a specific grind size. Here’s a guide:

Matching grind size to brewing method optimizes brew time, flavour clarity, and aroma intensity.

Even seasoned coffee lovers make grind size mistakes. Here’s how to spot and fix them:

Your grind size may need slight adjustments based on bean freshness and roast level:

Freshly roasted beans often release more CO₂, which can affect brew flow. Slightly coarsen the grind for espresso in the first week after roasting.

Light roasts are denser and may require a finer grind to extract sweetness and complexity.

Dark roasts are more brittle and extract faster, so you might want a slightly coarser grind to avoid bitterness.

To find the sweet spot:

1. Brew with your usual settings.
2. Taste carefully, note bitterness, sourness, or balance.
3. Adjust grind size in small increments (one notch on your grinder at a time).
4. Repeat until you achieve a balanced, sweet, and flavourful cup.

Specialty coffee enthusiasts often call this process dialling in, a fine-tuning ritual that rewards patience.

Grind size isn’t just a detail, it’s a major flavour driver. By matching your grind to your brewing method, using a burr grinder, and making small, thoughtful adjustments, you can unlock the full potential of your coffee beans.

Remember: coffee brewing is both science and art. The right grind size bridges the two, transforming good beans into unforgettable cups.

What grind size should I use for drip coffee?
A medium grind, similar to sand, works best for most drip coffee makers.

Can I use an espresso grind for a French press?
It’s not recommended. Espresso grind is too fine for French press and will make the coffee muddy and bitter.

How do I know if my grind size is wrong?
Bitter, harsh flavours often mean the grind is too fine. Sour, watery flavours mean it’s too coarse.

Is a burr grinder worth it for home brewing?
Yes, especially for specialty coffee. A burr grinder ensures consistent particle size, leading to better flavour.

Should grind size change with coffee freshness?
Yes. Fresh beans may require slightly coarser grinds in the first week after roasting to achieve a balanced extraction.