by Joseph Molloy July 19, 2021 6 min read
Coffee used to be just that- a monotonous, oily, bitter beverage. It tasted the same at home as it did at the local cafe. There was nothing much to it. Today, there's so much more to this cherished beverage. Coffee knowledge has broadened so much so, that for many, shopping for it has become just as confusing and frustrating as shopping for wine! For the average buyer, how the bean was roasted is a key determinant. In this article, we demystify this simple yet intricate process, to help you pick the most suitable roast level and most enjoyable coffee next time you go shopping.
The process has been described as both an art and science, but when it comes down to it, coffee roasting is simply the process of heating green coffee beans, to isolate and bring out their 'coffee' flavour and aroma.
Coffee beans come from a coffee cherry that has been picked, processed and then sent across the world to a coffee roaster for roasting.
Before the roasting process, green coffee is so hard as to be inedible. In fact, if you were to bite into one accidentally, you'd break your teeth. A green coffee bean is inedible until it has spent time at the higher temperatures a coffee roaster creates. Roasting makes the coffee bean expand and crack and puff up much as popcorn does. Hence, coffee roasting is an integral step in the coffee-making process.
The intensity (how hot) and duration (how long) of roasting play a critical role in the strength and taste of a brew. In fact, the many confusing words on a coffee bag usually simply describe roast degree!
Generally, roasts are distinguished using two frameworks; degree and strength. The two frameworks however communicate the same thing; intensity and duration of the roasting process. There are four degrees general degrees: light roast, medium roast, medium-dark roast and dark roast. The strength framework was adopted by supermarkets to simplify that concept and generally corresponds with the degree framework. There are 5 possible strengths, though most people find the first two to be too weak and as such, most supermarkets will only stock strengths 3-5.
If a bag of coffee doesn't have an indicator, it is almost always a light to medium roast. This however isn't the case for specialty coffee! Most specialty coffee roasters do not indicate roast degree on their products. Instead, they will either indicate what application suits a particular coffee best, i.e 'roasted for espresso' or 'roasted for filter coffee'. They may also describe the coffee's flavour i.e berry flavour.
Light roast coffee is achieved by roasting the beans for a shorter period of time, often around ten minutes. A lightly roasted bean is denser than a dark roasted bean because it retains more water from the roasting process. Moreover, unlike a dark-roasted bean, brews made from lightly roasted beans don't have that layer of oil on the surface. This is because the chemical process that happens when the coffee bean is roasted is not allowed to take its course. Contrary to popular belief, light roasts contain more caffeine than all other roasts. This is simply because light beans are denser than darker ones.
What of the flavour profile? Well, this is highly subjective, but generally, lighter beans are more acidic, fruity and brewed better as a filter.
Medium roasts strike a balance between lighter roasts and dark roasts. For this reason, medium roasts are popular with specialty coffee roasters. The flavor profile can have body, acidity, and sweetness and work well both black and with milk. A good medium roast will have a balanced flavor and suit most coffee drinkers.
Less often talked about, medium-dark beans occur when the bean is roasted long enough not to be medium but not quite long enough to be labelled dark. The result is a brew that possesses the complexity of a medium roast, but with the unmistakable coffee aroma present in darker roasts. Medium-dark is not as bitter as its counterpart.
For those looking for abundance in coffee flavour- dark is the way to go. Dark roast beans don't have as much caffeine as their counterparts, but they make up for it with flavour!
Dark roast coffees spend the longest time in the coffee roaster going so far as to approach or pass second crack (When the coffee reaches various temperatures the beans expand much like popcorn. All roasted coffee, even the lightest filter profile passes the first crack, but the second crack is reserved for dark and beyond french roasts.)
Aside from the darker-coloured brew, one can distinguish dark roast coffee by the oil produced when the beans are brewed. Coffee brewed with dark beans has low acidity but an overall bitter flavour.
Specialty coffee seldom uses the identifiers discussed above to guide the buyer. Instead, specialty coffee roasters specify whether that particular roast is suited for espresso or filter coffee. You may also see the phrase omni-roast being used on some batches from time to time. What do these terms imply?
When Specialty coffee roasters indicate that coffee is best used for espresso, they simply mean to say that the coffee beans used have been roasted under higher temperatures and for longer. Coffee beans meant for Espresso are roasted this way to increase solubility and lessen acidity.
On the other hand, filter coffee is roasted under lower temperatures and for a shorter period of time. The goal is to present the full flavour of the coffee bean and as such filter coffee tends to be more complex in flavour. While one can use espresso coffee in a drip machine or french press, filter coffee brewed in an espresso machine has an undesirable sour taste.
Omni roast coffee has a roast profile that aims to be usable both for espresso and filter coffee! It's a hard target to hit and many roasters believe it's
The term specialty coffee implies two things- quality, and transparency. It's not your ordinary coffee. The official definition by the SCA (Specialty Coffee Association) defines this type of coffee as the, "highest quality green coffee beans roasted to their greatest flavour potential by true craftspeople and then properly brewed to well-established SCAA developed standards.” Simply put, specialty coffee is the 'good stuff.'
SCAA standards call for coffee that exceeds the 80-point mark on the quality scale and is of excellent aroma, flavour, acidity, aftertaste, uniformity, body balance, sweetness and clean up. Specialty coffee is usually brewed from the best coffee beans- usually single origin coffee. Specialty Coffee roasters go to great lengths to ethically source their green beans. They build relationships with individual farmers and directly negotiate with them. Oftentimes, these roasters will indicate the specific farm from which their beans are sourced, and publish rates used to buy their beans.
Specialty coffee is usually reserved for true coffee lovers. These coffee drinkers will pay more for the best and often take out coffee subscriptions rather than buying from the supermarket or grocery store.
Melbourne is a booming presence in Specialty Coffee. The city is arguably the coffee capital of the world. Australian coffee roasters of note with a presence in Melbourne include Rumble Coffee, Axil coffee roasters Seven Seeds and many more.
Specialty coffee can only be roasted by certified coffee experts. The roasting process is keenly monitored using highly specialised tools to get the best out of the beans. The process must comply with standards set by the SCA.
Strength is confusing in coffee. Most people mean how strong is the flavour but sometimes they want to know about the caffeine content.
We'll cover flavour first. Dark roasted coffee has bold, chocolatey flavours when roasted well. When roasted badly, or too dark then it can taste burnt, smoky, ashy or even fishy. But full-bodied chocolate or cocoa is often considered strong.
Medium roast coffees can still have a full-body but will have more acidity and fruitiness. Modern specialty coffee roasters prize these attributes.
Light roasted coffee will have the least body and is recommended for filter brewing methods. It may have a high caffeine content but that is due to the longer contact time rather than the roast profile.
To recap, the roast type determines much of the flavour and caffeine levels. There are two ways of distinguishing coffee roasts - degree and strength. They both indicate how hot and how long the bean was roasted. Lighter coffee has more caffeine but less of the signature coffee aroma. Dark coffee has less caffeine but more coffee aroma. Specialty Coffee is made with the best single origin beans, roasted to bring out the full flavour profile of the bean. All the best as you explore the worlds most beloved beverage!
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