Nothing beats the sensation of drinking a freshly brewed cup of coffee to start off a day at work. How do we achieve that perfect cup of coffee? It all starts with the coffee bean.
The best kind of coffee is made from freshly ground wholly roasted coffee beans which has a rich aroma and incredibly pleasant flavour. The roasted coffee beans are ground according to the type of brew that you want for your coffee, and usually take only a matter of minutes to do. Grinding your coffee beans is essential to enable the coffee beans to release fragrant oils and help extract the aroma in the brewing process. The fineness of the coffee grind will affect the taste of the coffee, and you should adjust the grind size according to your preferred brewing method.
How to grind coffee beans – Grind Size and Brewing Method
In general, brewing techniques that expose coffee grounds to boiling water for longer periods of time require a coarser grind than faster brewing methods. This is because the finer the coffee grind, the more surface area is created between the coffee grinds and the heated water, which causes “over-extraction” of the essential coffee oils and aromas. This may lead to the coffee tasting bitter.
When the coffee beans are finely ground they should be brewed for a shorter period of time to prevent over-extraction from occurring.
In contrast, coarsely ground coffee beans should be brewed for an extended period of time; otherwise the coffee may taste plain and flavourless. It is important to achieve a consistent grind before brewing, as this will affect the taste and quality of the coffee.
Avoid Pre-Ground Coffee Beans
It is important to start grinding with whole roasted coffee beans. Grind your coffee beans right before brewing. This is important because whole beans keep the coffee oils and extracts protected inside the bean which preserves the flavour of the coffee. Do not use pre-ground coffee because once the protective shell of the coffee bean is broken, it will lose aroma and flavour and affect the taste of the coffee.
Coffees oils are delicate and dissipate easily when exposed to external elements. The cells inside the roasted coffee bean contain a good mix of delicate aromas and flavours. Once the coffee bean is split open and grounded, they interact with oxygen in the air due to oxidation and loses its fragrance. Approximately 60% of the aroma is lost in the process. Ground coffee is also exposed to moisture in the environment which affects the coffee oil extracts due to its water solubility.
Grinding the roasted coffee beans prematurely (and storing them for future use) also releases carbon dioxide trapped within the cells, which are essential in coffee brewing and flavouring your cup of coffee. This may affect the quality and the taste of coffee, making it less aromatic. When learning how to grind coffee beans, always start with wholly roasted coffee beans for the best results!
The best solution to avoid losing flavour and aroma is to grind your roasted coffee beans just before brewing your coffee. In that way, you will preserve the freshness of the coffee beans as well as enhance the flavour of your coffee, bringing out the essence of the coffee beans.
Types of Coffee Grinders – Burr vs. Blade Design
Most coffee lovers grind their coffee either by burr-grinding or by blade-grinding. The process of burr-grinding starts with a burr coffee grinder, which uses two revolving abrasive elements such as wheels or conical grinding elements in which the coffee beans are “crushed” in between them with little frictional heating. The process of squeezing and crushing the coffee beans releases essential aromas and oils which flavour the coffee during the brewing process, making the coffee taste richer and smoother. In general, a burr grinder will offer a range of grind settings from very coarse to very fine, making them suitable to grind coffee for various brewing methods such as espresso, drip or French press.
There are important differences between conical and flat burr grinders. Flat burr grinders have two flat plates or “burrs” which pulverize the coffee beans into a uniform grind. A conical burr grinder has one flat burr and one cone-shaped burr which grinds the coffee beans on both sides. Generally, conical burr grinders are considered to better quality grinds because they pulverize the beans over a larger surface area, and reducing the process of heat creation which preserves the freshness of the coffee. As a result, conical burr grinders are more expensive but if you can afford them they are a great investment for making the perfect cup of coffee.
Burr grinds may be either electrical or powered by hand. Typical vintage burr grinders are made of high quality polished wood and look very nice on the coffee counter. You can easily adjust the size of the coffee grind on hand burr grinders by adjusting the knob, which varies the spacing between the conical burrs (the smaller the space, the finer the grind) An electric burr grinder comes with automated settings and you can easily adjust the grind via a push of the button. There are some conical burr grinders which are portable and come with a clean, modern finish. You can read more about these portable burr grinders here.
The other type of coffee grinder is a blade grinder, which uses fast-moving blades to chop the coffee beans. While they are cheaper than the burr grinder counterparts, they are not ideal for grinding coffee because they tend to produce uneven grinds and generate too much heat during the pulverizing process. Blade grinders violently chop up the coffee beans, which creates an uneven mix of large and small coffee particles that affect the brew. An ideal coffee brew would have the coffee grind particles of the same size for a consistent brew. When coffee beans are chopped by the blade grinder, this often creates coffee “saw-dust” which are extremely minute particles that result from the impact of the blades on the roast beans. This results in “over-extraction” which may make your coffee taste bitter. The “coffee dust” also clogs up sizes in espresso machines and French presses – blade grinders are not recommended for grinding coffee for use with pump espresso machines. While burr grinders are more expensive than blade grinders, blade grinders are much faster and make less noise than a burr grinder, although the quality of the grind is not as good as the burr coffee grinder. Remember, the smallest change in grind size can result in a noticeable outcome in the cup of coffee, so for best results we always recommend getting a grinder with a conical burr design.
How long should you grind your coffee beans?
An often overlooked step when deciding how to grind coffee beans is to determine how long to grind them for. Depending on your brewing method, you may require a coarser grind or a fine grind and this is achieved is by varying the length of time of grinding. An interesting fact is that coffee grinds are measured in “microns”, with larger numbers referring to larger coffee particles. The standards grinding time are as follows:
Measuring the coffee beans
The most effective way to measure how much coffee beans to grind is by measuring the weight of the coffee. Coffee beans lose water content and swell in size during the roasting process. Hence, the longer the roast, the darker the coffee beans and the larger the size. This is why volume is not an accurate measurement of your coffee beans – one cup of heavily roasted coffee beans will certainly weigh less than a cup of light roasted coffee beans.
Weighing coffee beans with an electronic weighing machine produces the most accurate results
Weighing your coffee beans is a more accurate way to measure how much coffee beans to grind because you will take into account the variation in bean density. Secondly, it is more accurate than simply measuring the volume, which relies on visual approximation when you use a standard “coffee scoop”. This may lead to inconsistency in the flavour of the coffee brew.
It is great to invest in a digital weighing machine that can measure the coffee beans in grams and ounces. Find out what is the ideal measure appropriate for your coffee brewing method per cup of coffee and you can easily get started on creating the ideal coffee brew with maximum consistency. The key is that once you’ve learned what works with your preferred brew you can easily and consistently replicate the process, and correctly “calibrate” the grind according to your needs.
Other Factors that Influence Grind Quality
There are many factors that can influence the quality of the grind and affect how your coffee tastes. This is especially important when selecting which type of roasted coffee beans to purchase from your local store.
The first factor that can influence the grind is the roast level. The longer the roast, the more brittle the coffee bean due to the loss of moisture during the roasting process and the darker the coffee beans. The loss of moisture also causes the coffee beans to swell in size. Lightly roasted coffee beans are more flexible and firm, and are less brittle.
The second factor that influences the quality of the grind is whether the coffee was harvested from new crop or past crop. The goal is to roast the coffee as soon as possible, since green coffee gets woodier and woodier with every month in which it is stored.
This woody texture is responsible for “coffee-dust” that may result from grinding, which leads to over-extraction. Coffee beans from newer crop produces less fine dust particles than from past crop coffee, which makes the coffee taste smoother and aromatic.
Coffee beans that are roasted from freshly harvested coffee are of higher quality and have stronger aromas
The third factor is altitude – coffees grown at higher elevation (above 2,000 ft) grind different than coffees grown at a low altitude. The reason for this is that the higher the altitude, the slower the coffee beans mature due to the difference in oxygen content and air temperature – which results in a harder and denser substance.
Finally, the process by which the coffee is roasted may affect the quality of the grind. This is most relevant in the cooling of the beans – a process known as quenching. In the coffee industry, there are two types of quenching, known as air quenching and water quenching. Some roasters add water to the air stream that cools to the beans to kick off the cooling process.
This “water-quenching” process can damage the surface of the roasted beans if done incorrectly, and add moisture lost during the roasting process back into the beans.
Air-quenching is a more sophisticated process which cools off the coffee beans by pulling air through the beans – no water is added to the cooling process, which helps to maintain the quality and robustness of the coffee roast.
In conclusion, finding out how to grind coffee beans is an important step in ensuring that you can achieve the most consistent grind and bring out the flavour of the coffee beans.
Regardless of the type of brewing method you use, the most important aspect of grinding coffee is to break down the roasted coffee bean to expose the interior of the bean to allow the right amount of oils and flavours to be extracted.
This allows these aromas and oil extracts to seep into the coffee during the brewing process, which creates a smooth blend of heavenly coffee. It is important to remember that many factors can influence the quality of the coffee grind, but ultimately you should grind your coffee beans only before you are ready to brew.
Getting a high quality coffee grinder is also key in producing that perfect coffee brew – and for this purpose we highly recommend grinders with a conical burr design that can easily adjust the size of the grind. Couple this with high quality coffee beans and you are on your way to making the perfect cup of coffee!