UPDATED GLOSSARY OF TERMS
Arabica refers to a species of coffee. Coffee(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 each plant produces more coffee than arabica and is more pest resistant, but tends to be not as complex and sweet as arabica.
A term to describe a roast defect that inhibits or removes sweetness from a roast. A baked roast will taste like bread or cereal and sometimes ashy. This can be the result of a roast that lasts for a long time, with very little increase in temperature.
The temperature of the coffee bean, as measured in the roaster. This is usually measured by a thermocouple/probe that sticks into the mass that is being roasted, ensuring maximum contact between the coffee and the thermocouple. The IKAWA Home and Pro models do not have a bean temperature sensor; these are usually seen in larger drum-style roasters.
A coffee variety that’s pronounced “boor-bone”. 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, juicy and round.
The tan-coloured, paper-like material that collects in the jar during roasting. It is the dried and roasted silver-skin that is sloughed off of the green coffee bean during the roasting process. This can be composted and some have experimented with this as an ingredient in cooking.
The seed of a coffee fruit. Coffee begins its life as a fruit on a tree and the seeds of that fruit are what are dried, roasted and brewed as coffee.
Cupping is the method of evaluating coffee used by coffee professionals worldwide. This brewing and tasting method is often used for evaluating many coffees at once. The Method for this is to place medium coarse ground coffee in the bottom of a bowl or cup and hot water is added directly to the grounds. The coffee brews for 4 minutes, after which the “cupper” pushes a spoon into the bowl. Doing this will force the grounds to settle on the bottom of the bowl, leaving brewed coffee above. The “cupper” uses a spoon to take some of the brewed coffee from the top of the bowl to taste and evaluate.
A term to describe the CO2 that is produced during roasting. leaving the roasted coffee bean. Degassing happens for days and weeks after a coffee is roasted. We recommend that you wait 3-6 days before brewing coffee after roasting, as the CO2 can skew the flavour 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. While still being researched, it seems that higher density coffees score better and are easier to roast. Heat application in a roast will need to change based on the density of the coffee.
A term used to describe the time after 1st crack until the end of the roast.
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. Some widely regarded industry professionals have suggested that 20% – 25% DTR is the window where most roasts taste best, but this also depends on variety, density, and batch size as well.
The audible point in the roast where the coffee beans will pop or crack, much like popcorn. This is the point in a roast when coffee begins to taste like the coffee most of us know and love. First Crack tends to happen when the bean temperature is around 200C (392F).
A notoriously difficult and slow to grow variety with unparalleled intensity and quality of flavour, which means that it usually commands a premium price. Usually bright, light bodied and floral and often with notes like melon, citrus and white flowers.
Dried and stable “raw” coffee seed. After the coffee fruit/cherry seed is dried, it has a blue-green to yellow colour which it keeps until it is roasted.
After a coffee cherry is picked, the seeds/beans need to be dried and separated from the fruit to prepare for export. In honey processing, after the cherry is picked, the fruit is partially removed, leaving some fruit and the sticky, sugary layer called the mucilage on the outside of the seed. Coffees are then dried on raised beds or concrete patios.
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 or piled high into a pyramid like shape to keep the drying process slow.
Red Honey: a small amount of coffee fruit and all of the mucilage is left on the seed. It is dried slowly under shade, or piled into a high mound to keep the drying process moderately slow.
Yellow Honey: all of the fruit and most of the mucilage is removed. It is then dried much like a washed coffee.
White Honey: all of the mucilage is removed mechanically and it is then dried like a washed coffee. This is very similar to a washed coffee’s process, but the coffee does not come into contact with water.
The temperature of the air entering the roasting chamber. All IKAWA Home recipes use 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 variety of coffee that is characterised by its large size. Maragogype (Mara-go-heep-ay) can be more than twice the size of a “regular” bean like bourbon. Flavours vary, sometimes giving tropical fruit, sauvignon blanc and onion flavours. It can be difficult to roast because of its size, but tends to be hybridised with other varieties to make a more usual coffee. Pacamara is a Maragogype hybrid.
NATURAL PROCESS (OR DRY PROCESS)
After a coffee cherry is picked, the seeds inside (coffee beans) need to be dried to prepare for export. Natural processed coffees are dried with the fruit intact until fully dried, which can take anywhere from 20-35 days. Natural processing exerts a strong influence on the final flavour of the coffee. The coffee tends to be more fruity in flavour and creamy in body. Off-flavours like salt, must, mould, and more are possible if the fruit is not dried evenly. Naturals tend to taste best with a gentle approach to roasting.
PROFILE (ROAST RECIPE)
The temperature vs time graph of a roast. This can refer to any temperature sensor output. For example, the IKAWA Home roaster uses an inlet temperature measurement which has a different shaped profile to a bean temperature profile, which is why we refer to it as a Roast Recipe.
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 the rest of the ripe coffee that was roasted. Quakers are hard to pick out of green coffee but can be easy to spot in a roasted coffee. If a coffee cherry isn’t ripe when it’s picked, the seed will not roast to a normal colour or flavour, due to a lack of developed sugars and compounds. Once roasted, quakers tend to taste like grain. 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, using density sorting methods and machines.
RATE OF RISE
The change in temperature over a given period. 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 on an IKAWA Pro or a drum roaster. It will give an early indication to what is happening during the roast than that of the actual temperature probe. Generally speaking, coffee tastes best when it is roasted with a constantly declining bean temperature RoR. That is to say, the bean temperature is rising slower and slower 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 to 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 unlocked 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 without its unique 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, as every person has their own unique flavour preferences. For example, many roasters will take the same coffee and roast it one way for “filter” coffee and one way for espresso, and some will roast it light, dark or somewhere in between.
Roast development is a broad term which refers to the overall development through the roast. A roast's development does not solely depend on the time after 1st crack.
Coffee roasting is applying heat and time to green coffee to a point where they brown, crack and become drinkable. It can take as little as 4 minutes or can be drawn out over 20 minutes. The style of the coffee roasting machine, the heat applied, the batch size 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 IKAWA Home app recipe together.
A second, audible cracking of the coffee happens if a roast is taken far enough in time and temperature. This tends to sound more like a sizzle. The physical cell structure is actually cracking. After this point, oils can migrate to the exterior of the bean and roast flavours tend to interfere with the unique character of the coffee.
A drought resistant coffee variety developed by Scott Labs in the 1930’s specifically for Kenya. The variety has since been planted all over the world. SL-28 in Kenya tends to be intensely acidic, sweet and juicy, and have flavours of berries, black tea, red wine 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 grind and are difficult to extract. Flavours can be sour, metallic, hay-like and more. Under developed coffees do not have as many developed sugars and acids so they tend to under extract which magnifies the already negative flavours.
After a coffee cherry is picked, the coffee beans inside need to be dried to prepare for export. After the cherry is picked, the cherry fruit is removed (usually within 3 – 48hrs), the sticky, sugary layer called the mucilage is removed, the coffee is washed in water and the seeds (coffee beans) are dried.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.
Washed process coffees, in comparison to honey and natural processed coffees, are generally lighter in body and have complex acidity, with citrus and light fruity flavours being most common.
Reference to the variety of coffee plants, under the species of Arabica or Robusta. 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, gesha, bourbon and maragogype.
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