It can sometimes be difficult to find clarity in coffee terms. We’re here to help.
Arabica refers to a Species of Coffea. Coffea has two main species – robusta and arabica.
Arabica coffee is the overwhelming favourite for people when it comes to taste. Robusta is grown because it is higher yielding and more pest resistant, but does not have the complex, sweet taste of arabica.
Within the arabica species there are different varieties, such as bourbon, geisha, SL-28 and 1000’s more.
A term to describe a roast defect that inhibits or removes sweetness from a roast. Sometimes this will taste like bread or cereal (think Cheerios), and sometimes ashy. This is the result of the Rate of Rise of a roast increasing after 1st crack.
The temperature of the coffee seed (bean) measured in the roaster. Usually measured by a thermocouple/probe that is in the coffee bed in the roaster so there is maximum contact between the coffee and the thermocouple. Neither of the IKAWA models has a bean temperature sensor, it is usually seen in larger drum-style roasters.
Bourbon (coffee variety)
no, not whisky, but a coffee variety that’s pronounced something closer to “boor-bone”. And what a classic. A friend of the professionals and rookies, diners and cafes, the bourbon variety is an ancient one and can be traced back to some of the first plants taken from Ethiopia in the 16th century. Flavours vary but it’s very sweet, lush and round.
The tan-coloured, tough, papery-like material that collects in the jar during roasting. It is the dried and roasted silver-skin from the green coffee bean.
A coffee cherry seed. Coffee begins it’s life as a cherry on a tree and the seeds of that cherry are what are dried, roasted and brewed as coffee.
Cupping is a professional method of evaluating coffee. This brewing and tasting method is often used for evaluating many coffees at once.
Method: coffee grounds are placed in the bottom of a bowl or cup and water is added directly to the grounds. The coffee steeps for 4 minutes, during which time the coffee, full of CO2 gas, floats on the top of the water to create a crust. At 4 minutes, the “cupper” pushes a spoon over the top of the coffee/water mixture to break the coffee crust and the grinds settle to the bottom leaving brewed coffee above. The cupper uses a spoon to take the brewed coffee from the top of the cup and taste.
Much of the world’s coffees are purchased at a cupping table. Buyers and producers will set up table after table of coffee to taste them all side by side, evaluating to determine price and use.
A term used to describe the phenomenon where the CO2 that is produced by the chemical reactions that take place during roasting leave the roasted coffee bean. Degassing is powerful and can blow up a bag, hence the need for a one-way valve in coffee packaging. Degassing happens for weeks after the roast happens but is at it’s peak for the first 3 – 6 days. Some, coffee roasters will age their coffee beans for 4 – 6 weeks before shipping to customers so that degassing has finished, making it slightly easier to dial in espresso, however we find that that method significantly disrupts the quality of the coffee.
Mass per unit volume. In other terms, it’s how heavy something is based on a set volume. If you have exactly 1000mL of 3 different coffees, the weight / mL is the density of that coffee. Why is it relevant? While still be researched, it seems to be consistent that higher density coffees score better and roast better. Heat application in a roast will need to change depending on the density of the coffee.
An older term still used for the time after 1st crack until the end of the roast. Keep in mind that a coffees development is not dependent solely on the time after first crack. The entire roast is responsible.
Development Time Ratio (DTR)
[ time after 1st crack ] / [ total roast time ]
A useful measure for roaster operators to keep an eye on. The time after 1st crack sees rapid changes in flavour, colour, acidity levels and body. Scott Rao, through much research, has suggested that 20% – 25% DTR is the window where most roasts taste best.
The temperature inside the roasting chamber. The IKAWA Pro Sample Roaster uses this measurement to track the roast.
The temperature of the air exiting the roasting chamber. In some roasters this can be very similar to the environmental temperature, and in others be quite different.
The audible point in the roast where the coffee seeds (beans) will pop or crack, much like popcorn, although with much less physical change than popcorn. It’s the point from where coffee begins to taste like the coffee most of us understand and love. First Crack happens around 200C (392F).
a heralded variety, notoriously difficult and slow to grow but with unparalleled intensity which means it’s usually attached to a premium price. Usually bright, light bodied and floral and often with notes like melon, citrus and white flowers. If you haven’t tried it before, a good example is unlike any coffee you’ve ever had.
Dried and stable “raw” coffee seed. After the coffee cherry seed is dried, it has a green colour which it keeps until it is roasted.
After a coffee cherry is picked, the seeds inside (coffee beans) need to be dried to prepare for export. After the cherry is picked, the cherry fruit is partially removed, leaving some fruit and the sticky, sugary layer called the mucilage. In many Central American countries, the mucilage is called “miel”, which translates to “honey”. Coffees are dried on mesh beds like natural processed coffees to avoid fermentation and mould.
Honey processing is also known as “semi-washed” or “pulped natural”. Honey processed coffees are variable, and the producer can choose how much fruit and mucilage to leave on. This will affect the cup profile.
Black Honey: much of the coffee cherry and all of the mucilage is left on the seed. It is dried very slowly under shade.
Red Honey: a small amount of coffee fruit and all of the mucilage is left on the seed. It is dried slowly under shade.
Yellow Honey: all of the fruit and most of the mucilage is removed. It is dried like a washed coffee.
White Honey: all of the mucilage is removed mechanically and it is dried like a washed coffee. Very similar to a washed coffee, but it is not washed in water.
The temperature of the air entering the roasting chamber. The IKAWA At Home uses this for tracking roasts.
The percentage of the overall weight of a coffee that is water. Most coffees are exported between 9 and 11.5% moisture content.
a giant bean, maragogype can be more than twice the size of a “regular” bean like bourbon. Flavours can be mild to wild, sometimes giving tropical fruit, sauvignon blanc and onion flavours. Can be difficult to roast because of it’s size.
Natural Process (or dry process)
After a coffee cherry is picked, the seeds inside (coffee beans) need to be dried to prepare for export. Naturally processed coffees leave the cherry fruit intact and on the seeds while it is dried. The best natural processes dry the cherries on screen beds where air can circulate on all sides and the cherries are manually turned every few hours. This reduces the chance of off flavours from unsavoury fermentation.
Natural processing exerts a strong influence on the final flavour of the coffee. The coffee tends to be more fruit forward, lower in acidity and creamy in texture. It is difficult to execute well, and off-flavours like black olive, brine, ferment, must, mould, and more are possible if the fruit is not dried well.
Naturals tend to need a more delicate approach to roasting.
The temperature vs time graph of a roast. This can refer to any temperature sensors output. For example, the IKAWA At Home uses an inlet temperature measurement which has a different shaped profile to a bean temperature profile.
While most coffee cherries have 2 seeds in them (flat sides facing each other), about 15-20% of cherries on a coffee shrub will have only 1 seed inside. Because there isn’t another seed to push against it, it develops as a round seed instead of a half-circle like most.
A term used to describe an unripe coffee seed, usually after it’s been roasted when it’s a dramatically lighter colour than a ripe seed.
If a coffee cherry isn’t ripe when it’s picked, the seed will not roast to a normal colour or flavour, lacking the same compounds required. They can taste like Cheerios, cereal, burnt meat, or worse.
Good picking and sorting at the farm and mill level will keep almost all quakers out of a coffee. There are many stages at which they can be removed – while in the cherry, as undried seeds and dried seeds.
Rate of Rise
The change in temperature over a given period of time. It’s often measured in rates of 15 or 30 seconds. If we use 15 seconds for an example, a RoR of 5 would indicate that the temperature will rise 5 degrees in 15 seconds. A RoR of -2 indicates the temperature will drop 2 degrees in 15 seconds.
This is a very useful tool for roasting. It will give an earlier indication to what is happening during the roast that the actual temperature probe. The RoR can be measured for any of the temperatures being tracked during a roast.
We know that after the initial spike, coffee generally tastes best when it’s roasted with a constantly declining bean RoR. That is to say, the bean temperature is rising a slower each second through the roast.
A non-specific term describing the progression of roasting. A good roast is said to “develop” a coffee. In roasting, we cannot add or change the flavour of a coffee, we can only unlock what is already in the green coffee.
A good roast is developed, which means there isn’t any undesirable flavours from “under development” and the coffee is easily soluble in hot water.
A roast that didn’t go far enough/hot enough is said to be “under developed” and leaves behind potential in the coffee. A roast that went too far is said to be “over developed” and the roast has destroyed most of the good in the coffee leaving it empty and without character.
Over development is tricky because there isn’t a perfect window for a coffee. The same coffee can be presented in many different ways to satisfy a coffee drinker. For example, many roasters will take the same coffee and roast it one way for “filter” coffee and one way for espresso.
Confusingly, this is a new term and comes after the term “development time” which only refers to the time after 1st crack. Roast development is a broad term which assess the overall development all the way through the roast.
NOTE: A roasts development does not solely depend on the time after 1st crack.
Coffee roasting is heating up dried coffee seeds (green coffee) to a point where they brown, crack and become drinkable. It takes as little as 4 minutes (like in the IKAWA) or can be drawn out over 20 minutes. The style of the coffee roasting machine, the heat applied, and the time of the roast all play a factor in determining how the resulting coffee will taste.
The combination of a green coffee and the perfectly suited roast profile.
A second, audible cracking of the coffee happens if a roast is taken far enough in time and/or temperature. The physical cell structure is actually cracking. After this point, oils can migrate to the exterior of the bean and roast flavours can interfere with origin flavours.
A coffee variety and a coffee geek’s favourite. Developed by Scot Labs in the 1930’s specifically for Kenya and to be drought resistant. The flavour still seems to peak in Kenya, although it’s being planted expectantly all over the world. SL-28 in Kenya tends to be intensely acidic and sweet which gives a “juicy” overtone, and can produce notes of blackberry, currant, raspberry and more.
A roast defect that occurs when the bean temperature stops increasing for a significant amount of time. It is difficult to identify exactly in taste, but has been identified to have negative impacts on flavour.
a device that will provide a temperature measurement through an electrical signal
a type of temperature sensor. It is a probe used to measure temperature
Under development (see also “roast development”)
Under developed coffees tend to be difficult to break open with your fingers, are hard on your grinder, and difficult to extract. Flavours can be “green”, sour, tinny or metallic, hay-like and more. Under developed coffees are less soluble so they tend to under extract which magnifies the already negative flavours.
Keep in mind that a coffees development is not dependent solely on the time after first crack. The entire roast is responsible.
After a coffee cherry is picked, the seeds inside (coffee beans) need to be dried to prepare for export. After the cherry is picked, the cherry fruit is removed (usually within 3 – 48hrs), a sticky, sugary layer called the mucilage is removed, the coffee is washed in water and the seeds (coffee beans) are dried.
Washed process coffees, in comparison to honey and natural processed coffees, are generally cleaner in flavour, more acidic, lighter in body and arguably display more terroir and varietal characteristics.
Washed processing also uses water channels and pools to transport and sort coffee. Initially, cherries that float in water are separated and later, after the fruit is removed, the coffee seeds are roughly separated by density in washing channels. This is a major factor for why washed coffees have historically been cleaner than natural processed coffees.
Reference to the variety of coffee plant. We all know arabica vs robusta. IKAWA prefers only arabica. And when we dig a little deeper into the arabica side of things, we discover varieties of arabica. Like wine, coffee has varieties which have individual agricultural needs, physical characteristics and flavour profiles.
Many varieties of coffee are natural mutations or hybrids that excelled in that particular environment, but many these days are created intentionally. Different climates and soils will render different characteristics in a coffee. See some of our examples here, SL-28, geisha, bourbon and maragogype.