At Sea Island we often get asked about the best way to brew coffee at home; what machine should I buy? What brew method should I use? What is the ideal brew ratio for such and such beans? Sometimes these questions are easily answered, but sometimes it takes a little bit more digging for me to find out the best way I can help this person brew the best possible coffee at home. Inevitably the first question I ask is "Are you grinding the beans yourself?"
This article will help explain why this is my go-to question, and why grinding really does matter.
To simplify matters, coffee after processing exists in four different stages; green bean, roasted beans, ground coffee and brewed coffee. Green beans can stay fresh for up to a year, or longer depending on who you ask; roasted beans start to lose their flavour after a few weeks, brewed coffee after a few minutes, and ground coffee after forty five seconds.
The reason behind this is to do with the chemical makeup of coffee. Whilst green beans (unroasted coffee) have been found to contain approximately three hundred different Volatile Organic Compounds (VOCs) responsible for aroma and flavour; roasted coffee has been found to contain over a thousand due to chemical reactions throughout the roasting process.
The problem is that these aromatic compounds are volatile, meaning they have a tendency to 'sublimate' from a solid (beans or grinds) or liquid (brewed coffee) into the air. The issue with ground coffee is that is has a much larger surface area than whole beans. This allows the VOCs to escape much quick from ground coffee. After just forty-five seconds you already start losing the aromatic compounds that turn a regular cup o' Joe into a truly special coffee.
WHAT IS GRINDING
Grinding coffee is basically the act of breaking roasted coffee beans down into smaller chunks thus allowing the compounds in the coffee to be easily dissolved or suspended in water, resulting in a coffee. There are two main categories of coffee grinds, as dictated by the coarseness or fineness of the grind; espresso or filter. Espresso grind is extremely fine and designed to be compressed into a 'puck' of ground coffee to pass water through at pressure, filter grinds can vary from the consistency of table salt up to coarse sand.
Due to the high pressure and aggressive nature of espresso, an espresso grind is much harder to get right than a filter grind. It needs to have a highly consistent grind size and care needs to be taken that the burrs or burr housing does not get over-heated and cause VOCs to breakdown or sublimate from the coffee. As such, a better grinder is normally required when grinding for espresso. Qualities to look for in a good espresso grinder are: low RPM (revolutions per minute), an ability to make fine adjustments to the grind, a high quality burr set and a built in timer to control the weight of the grinds.
You will also see grinders advertised with 'flat' burrs, or 'conical' burrs. Simply put, conical burrs allow the motor to spin slower, resulting in a more consistent grind with less heat build-up, a feature you will find in both our Baratza Encore and our Vario Home.
For filter, the requirements are a little less strict due to the more relaxed nature of the brewing process. However, it is still important that the quality of the grind is of a consistently high quality. You should always ensure that you are using a coffee grinder with two burrs rather than a grinder with spinning blades for both espresso and filter.
The reasoning behind this is due to the inconsistencies in grind fineness with a blade grinder. In the same way as cooking vegetable, if your grind is inconsistent the smaller grinds will brew faster than the larger grinds resulting in a poor extraction. Also, blade grinders can take a lot longer to grind the same quantity of coffee as a burr grinder, resulting in a build up of heat which can break down the aromatic compounds within the coffee.
To simplify the advice given, always consider which grinder would be an ideal choice for your brew method. If you're brewing filter, our manual Hario Slim or Baratza Encore grinders would be ideally suited (though if you don't want a work out first thing, the Hario Slim may not be for you).
FOR THE HOME
If you are looking to brew espresso at home, we highly recommend the Vario Home for its versatility, high quality burr-set and innovative grind adjustment system. Just remember, it doesn't matter how great your brew equipment or method is, without a great grinder, you are missing out!