When you buy our Bloody Good Coffee, either in-store at Sherborne or online, we always ask, "How do you make your coffee?". Beyond just friendly chatter, there's a vital reason for this question. We aim to understand your brewing method to select the best grind size for you. We want to ensure that regardless of your chosen method, your coffee tastes absolutely amazing every single time.

The Basic Science of Grind Size

Shifting your mindset to think of ground coffee as 'particles' clarifies our approach. The grind size and the contact time with hot water are interrelated:

Longer Brew Times = Coarser Grinds: For methods like the cafetière, which lets coffee steep for 4+ minutes, a coarse grind is ideal. This allows the water sufficient time to extract flavours from the coffee particles.
Shorter Brew Times = Finer Grinds: For espresso, where the water's contact time is around 30 seconds, you'll need a very fine grind. This ensures optimal flavour extraction in such a short time span.

Sounds straightforward, right? While the basic principle is easy to grasp, there's a bit more to it (and it makes you feel a bit like a scientist!).

Diving Deeper: Coffee Chemistry

When roasted, coffee's solubility increases. Combining ground coffee with water dissolves certain soluble coffee compounds, turning it into a flavourful solution. The hotter the water, the faster the dissolving occurs. There are 3 main factors influencing the process, these include:

Time of brewing
Temperature of the water
Surface area of the coffee particles

I mentioned the temperature of water above, but for this post we'll keep our focus on time and surface area and assume our water temperature remains constant at 98°C.

For methods like cafetière where the brew time is around 4-5 minutes, the coarser grinds expose a smaller surface area to the water, necessitating the longer brewing time to get maximum coffee flavour. Using a very fine grind for this method would result in an overly gritty coffee with a muddy texture and a massively over extracted (think burnt and bitter) flavour.

On the other hand, using a coarser grind for espresso would lead to weak, overly diluted, under extracted coffee (think insipidly weak coffee water). The fine grinds used for espresso offer a vast surface area, ensuring rapid flavour extraction in roughly 30 seconds. The initial burst of an espresso shot is intense, picking up maximum amount of soluble coffee flavour initially, then gradually weakening as the extraction continues, combining everything over the 30 seconds creates a balanced and delicious espresso. Its also the reason why you should stir an espresso before drinking it.

The Mechanics of Grinding

How do we achieve the right grind size? A speciality coffee grinder's operation resembles that of a flour mill, only with sharp teeth rather than just being flat. Now, for those scratching their heads, thinking, "Flour mill? Why that analogy?", let's elaborate a touch. Much like our coffee beans, grains in a flour mill are broken down between two plates or stones. The main aim is to get a consistent size, ensuring that every grain (or in our case, coffee bean) is broken down uniformly. The only difference is, while flour mills use flat surfaces to crush and grind grains, coffee grinders employ sharp teeth for a more precise cut.

Speaking of precision, let's talk about grinders. Blade grinders, with their spinning blade at the bottom of a chamber, may be the go-to for many who are starting out in their coffee journey, but they have their shortcomings. Their lack of consistency gives you an uneven mix of grind sizes, ranging from large chunks to dust-like fines. This inconsistency leads to unpredictable and unpalatable flavours in your brew.

Enter the burr grinder. The superior sibling in the grinding family, burr grinders utilise two burrs or discs, one that rotates and one that remains stationary. The coffee beans are cut and crushed between these blades, offering a much more consistent grind size, a result far superior to blade grinders. With a burr grinder, every tiny particle of coffee is almost identical in size, ensuring an even extraction of flavours and aromas. The result? A cup that's predictably perfect every single time.

Why Blade Grinders Aren't the Best Choice

If you’ve ever wondered why after using a blade grinder your coffee tastes inconsistent between brews, the blade grinder might be the reason. A mix of grind particles produce under-extracted flavours from the larger chunks, with over-extracted flavours occurring from the powdery fines, leading to an uneven and unbalanced tasting coffee.

So, while starting with a blade grinder can still be a vast improvement over pre-ground, supermarket shop bought coffee, there's a ceiling to the quality you can achieve. We encourage you to experience coffee ground with a burr grinder, which provides a more consistent particle size. When you want to test the difference, let us grind your next bag of coffee for you and you can taste for yourself.

The Way Forward: Let Us Help

Our commitment goes beyond just selling beans; it's about ensuring you have the best coffee experience possible. If you're ever uncertain about the grind size for a new brewing device (Aeropress anyone?), or want recommendations on brewing methods, don't hesitate to ask. Our team is always eager to share their knowledge and passion.

Furthermore, our Bloody Good Coffee beans have received accolades for their quality, such as The Brue gaining a 2 Star Great Taste Award from The Guild of Fine Food Judges. But the true magic actually happens when they're ground just right. Whether you prefer to buy online or in-store, we're always here to guide you.

For those looking to dive deeper into the world of coffee, keep an eye out for our future blog posts. We'll delve into topics like over and under-extraction, the nuances of different brewing methods, and much more.

Closing Thoughts

A perfect cup of coffee is a culmination of many factors: the bean quality, roast level, brewing method, and of course, often the most important factor - the grind size. By paying attention to each element, you elevate your coffee experience from ordinary to extraordinary.

So, the next time you're about to brew a cup, remember the importance of the grind. And if you're ever in doubt, remember we're just a chat away or available on the socials (FB - IG). With every bean and every grind, we're here to make sure you enjoy a truly Bloody Good Coffee. After all, life's too short for anything less!

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Grind Size and Your Coffee: Why It Matters