When it comes to coffee capsules, hot water is basically forced through your grounds: too fine, and it won’t get through, too coarse, and it will gush through.
Grinding: You can grind your own coffee beans fresh at home, or ask your favourite cafe to grind the beans for you. When grinding at home, you'll achieve the best results using a burr grinder, as blade grinders may create too much dust. If you require a fine grind for espresso or use with coffee pods, it's even more critical that your grinds are uniform/consistent. If you're having trouble getting your coffee right, buying pre-ground may be a better option than using a blade grinder.
Grind size: In general, a fine grind works best for reusable pods - this means that the water has to work a little harder to get through that ground coffee, creating strong, fuller bodied espresso and a beautiful extraction. Whereas a coarser grind tends to produce gentler flavours and a lighter colour crema. For the majority of our reusable pods, we recommend using a medium-fine for optimal results. If using our VertuoLine or Dolce Gusto compatibles, a fine grind is best.
Check out the following articles for an in depth look at how your grind method can affect your final brew:
Sourcing Coffee For Your Reusable Pods