How-To-Roast-With-IKAWA.Pdf

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How to roast with IKAWA

A guide to start understanding your green beans and learn to roast them to your taste. Content

03 FOREWORD

04 GREEN COFFEE

05 PROCESSING

06 HOW TO TALK ABOUT FLAVOURS

09 ROASTING TECHNOLOGY

13 CONTROLING THE ROAST VARIABLES

14 KEY STAGE OF ROASTING

18 PRINCIPLES OF ROAST COLOURS

20 HOW TO FIND YOUR PERFECT ROAST LEVEL

2 Foreword

We have really enjoyed bringing this together for you and we hope it helps to give you some guidance as you start your coffee roasting experience. Some of the content is new but a lot of it is leaning on guidance we have accumulated over the last few years in different places. It is by no means exhaustive, as you will see, and is designed as a foundational grounding in coffee roasting as it relates to the IKAWA home roaster.

The art and science of roasting coffee is a complex one. Professionals spend their entire careers perfecting it, in much the same way as a photographer or a wine sommelier would. It takes theory, sure - but most of all it takes experience and time. You now have, right there in your kitchen (and on your phone), everything you need to gain that experience. And it’s up to you how far you take this.

Ultimately, we are in pursuit of the perfect cup of coffee for us and our loved ones - but the process of learning about how to roast coffee effectively can be an extremely enjoyable one (and luckily involves a lot of tasting to do properly!).

Have fun with it. And as always, if you have any feedback for us we would love to hear it.

Onwards. Bradley - GM IKAWA At Home

3 Green coffee

Coffee is the seed of a fruit, often that affect a crop’s characteristics referred to as ‘cherries’. The fruit - altitude, soil type and quality, trees are grown at high altitudes, topography and farming practices. typically between the Tropic of Cancer and the Tropic of Capricorn. Roasting (i.e. applying heat) has a huge impact on the coffee taste, The coffee cherries grow slowly but it cannot change the inherent at these high mountain altitudes flavours of the beans. A coffee that (usually 1400 and 2000 metres naturally has the potential to taste above sea level), and can take nutty can’t be roasted to change its between 8 and 11 months to ripen. flavour to fruity. Once ripe, they are picked and processed shortly afterwards. It can only present the flavours of a bean or add to it in specific ways Once harvested and processed, the through flavours that come about coffee is set out to dry, which takes in the chemical reactions that 10-20 days, stored, then prepared take place such as caramelisation for export. It’s at this point that it is and browning - also known as the called “green coffee” and now it’s maillard reaction. (More on that over to you. later)

The flavours of the coffee may be We could write a whole book about dictated by variety, processing, and green coffee, coffee growing terroir (such as soil, altitude, and regions and all of their nuances. climate). Needless to say, differences in variety and region, affect the Terroir is a word that we hear more resulting flavours and may require and more in the coffee world, but different roast parameters for the it’s been used in farming, wine and optimum roast. For now, we would fine food for years. Coming from suggest keeping note of the coffee French, it can be defined as an varieties and processing that you ecosystem in a region. It is often are roasting and enjoying, as well used interchangeably with the term as trying to spot any commonalities ‘microclimate’. between coffee’s terroir (for However that term doesn’t take in example, altitude). consideration all the other factors

4 Processing

Before we move on to the roasting by using water. Once the fruit is itself, it is worth reviewing how removed, beans are dried. As you processing can affect the flavour of would imagine, this results in a coffee quite significantly. crisper, cleaner flavour: increased acidity/sparkle, lighter body, and This is the necessary act of removing arguably allows for a better flavour the fruit and it’s protective layers representation of the inherent from the coffee seeds and then characteristics of the beans. drying the seeds to a low, stable moisture content. This can be done Semi-Washed (also called ‘pulped in several different ways and can natural’ or ‘honey’) processed significantly affect the flavour of a coffees follow a hybrid approach coffee. of the above two: where the cherry fruit is removed but the mucilage Generally, there are 3 main is left on the beans for drying. This categories of coffee processing: process will impact the flavour by taking the best parts of washed Natural (also known as ‘dry’ or (clean cup) and natural (heavy ‘whole fruit’) processed coffees sweetness). leave the cherry fruit intact and on the seeds while it is dried. This is Coffee and its flavours are complex typically done on screen beds (for to say the least. Even coffees that best air circulation on all sides) in are of the same variety, processed natural sunlight. This process has a the same way, can have different strong influence on the final flavour characteristics depending on where of the coffee and tends to be more it is grown. We aim to learn from fruit forward, lower in acidity, and your experiences roasting different creamy in texture. coffees.

Washed processed coffees involve We suggest that you try out similar removing the cherry fruit and roast recipes on coffees with similar the sticky, sugary layer called the characteristics. mucilage from the coffee beans,

5 How to talk about flavours

There’s no right or wrong way to talk A note on “body” about flavours. Every individual has For the purpose of our use, we their own experience with taste and define ‘body’ as the texture; ranging smell- there is no ‘perfect’ way to from light to heavy. describe coffee. Light texture or body feels light in While there is no ‘perfect’ way the mouth, it doesn’t linger, perhaps to describe coffee, we really like it reminds you of a green tea. the work done by CoffeeMind. In Heavier body feels like it’s coating this diagram, you will see simpler the mouth. descriptors on the outside, and more complex descriptors as you Perhaps a heavy bodied coffee move towards the centre. reminds you of the texture of syrup, or cream. How a coffee is roasted, When learning how to describe can affect the resulting body. coffee, think of common food and drink that you have had before. If you have never experienced the sweet acidity of a strawberry, you will have a hard time picking that note out of a coffee. Also, sometimes coffee simply tastes of coffee.

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credit - coffee-mind.com

Roasting technology

Behind it’s aesthetic appeal, the The air, now hot, is blown into the It continues these tiny cycles of IKAWA home roaster is a smart roasting chamber and is doing sev- measurement and adjustments un- piece of engineering. Paired with eral things at once… til the roast has finished. At the end the App, you have everything of the roast recipe, the fan kicks up you need to apply heat to green - It is transferring heat to the beans a gear to allow fast cooling of the coffee beans precisely, in a con- as it passes around and through it. beans before being ready to ‘eject’. trolled and repeatable way. - It is moving the beans allowing Heat transfer Pressing that start button begins a evenly distributed heat transfer The most important thing in roast- process of complimenting systems (also known as “airflow” - the power ing, is applying heat to the coffee that make sure the coffee is roasted of which is controlled by the black beans. This heat is what causes in the way that you or our recom- line on your App). chemical reactions to take place in mended recipes have programmed. the beans. Besides processing, vari- - And finally, it is entering the roast- ety etc., heat applied in key stages When you press the start button, ing chamber in such a way that cre- of the roast has the biggest effect on the fan motor, the only moving ates a cyclone effect - important to the flavour of the end result. component of the machine will be- ensure evenness, prevent smoke gin rotating. The fan does many build-up, and to neatly collect the There are three methods of heat things, most importantly for now, chaff as it separates during the transfer and the IKAWA Home roast- it draws room temperature air into roasting process. er seeks to maximise the impact of the roaster. This air is then moved Convection heat transfer, whilst min- upwards into the roasting chamber, Throughout the roast, electronics imising the impact of the other two, past an electric heat source. As the are simultaneously receiving data Radiant and Conduction heat trans- air is moving past the heat source, from the temperature sensor and fer. This is to allow the most control the temperature is measured by a using that data to make adjust- possible. Let’s take a look at this. precise temperature sensor (this ments to the heat source according is the temperature you will see on to the roast recipe that has been your App, referred to as the “inlet” sent to the roaster. This same pro- temperature). cess is used to ensure the airflow , the speed of rotation within the fan motor, is accurate.

9 Convection Heat Measuring temperature These two different approaches to While there are elements of Radiant We are measuring the temperature measuring the temperature - ‘inlet’ and Conduction Heat transfer in the of the air immediately after it has and ‘bean’- are aimed at the same Ikawa Home roaster, these methods passed through the heat source, thing: to control and roast a coffee of heat transfer are minimised by us- using the internal PT1000 tempera- really well. ing aluminum and other materials ture sensor. We call this measure- that do not retain heat energy. The ment the “inlet” temperature be- Of course, these two measurements main method of heat transfer in the cause it’s the temperature of the air will correspond to one another. In Ikawa Home roaster is Convection. input to the beans. the same way slamming the brakes on a car would eventually lead to Through Convection heat transfer, In most other roasting machines, the car stopping, drastically de- the Ikawa Home roaster heats the the temperature is measured in a creasing the temperature of heat air that is blown into the roasting position that better represents the applied will pause the coffee from chamber, heating the coffee beans. actual temperature of coffee beans roasting further. The air might need to be heated to (often called the “bean” tempera- For the purpose of changing a roast a very high temperature or kept at a ture). To do this, these machines recipe, we can use the inlet tem- low temperature, based on the cof- need to use a more durable and perature to control the acceleration fee being roasted. therefore less precise (increased or deceleration of the heat input resistance for those who know!) and we can use distinct (and visible) The heat in air is much more con- temperature measurement device - stages of a roast to understand ‘how trollable and fit for our purpose of sometimes called a probe. fast the coffee is travelling’. We’ll roasting coffee precisely according come back to these stages shortly to our programmed recipe.The tem- This would not suit our needs be- and look at how understanding of perature of the air is programmed cause of the importance our ma- how an IKAWA home roaster is con- and measured using a very accurate chine places on the temperature trolled, can help us to change them. PT1000 temperature sensor. measurement and the role it plays in how we control each roast - requir- Now we know how the roasting ing precision and fast-reaction. technology works, how it transfers heat, and how it measures temper- This makes IKAWA home recipes ature; we can look at how to pro- look very different to the average gramme it through the three roast roast profile you will find on google control variables. or books written by Coffee Gurus.

10 11 Controlling roast variables

Temperature and Time Airflow How much airflow it takes to achieve Changing the temperature repre- This is controlled by the black line, this can vary depending on how sents the most important way we expressed as a % between 60% - dense and fresh the green coffee is. can change our roasts because heat 100%, and can be changed with up application has, by far, the largest to three points, four if we include Density and freshness are important impact on the different roasting cooling. This line represents the to bear in mind, if for example you stages. speed of the fan motor (the RPM) notice your beans not moving free- and, as we have read, this is what ly enough, particularly at the early On the IKAWA Home App you is necessary to apply heat, rotate stages of a roast when the beans will see this as the red line plotted the beans, and create the cyclone have not dried out yet and are heav- across temperature and time. And system. ier than they would be at the end of we have up to six points that we can the roasting process. add, remove, and change, to shape Airflow can dramatically change our recipe. the process of transferring heat to Within reason, there’s not necessar- our coffee beans but the full extent ily a right or wrong way here and we We can change these points by as of this is beyond the scope of our recommend focusing on the tem- little as one degree and one second introduction. perature controls as you get started. giving us an almost infinite range to work with. Fundamentally, the airflow needs As you become more comfortable to be moving the coffee beans with roasting, experimenting with Exceptions are that we cannot freely in order to provide even airflow as a way to change the key apply temperatures above 290c (or heat distribution and to avoid over- stages of a roast can be really inter- 554f) to maintain safety (and to be roasting the bottom (or under- esting. A forewarning: a small ad- honest, because we wouldn’t want roasting the top) of the coffee. justment to airflow/fan speed is the to anyway!) and we cannot roast best way to start experimenting. longer than 12 minutes (for similar reasons).

12 Key stages of roasting

How do we change flavourless green coffee into something so delicious?

Warning: do not attempt to try brewing green coffee. You will most certainly break your grinder!

13 Amazingly, to create all the chem- Drying Browning (Maillard) ical reactions needed, all we have As we begin to apply heat, the beans As the roast progresses, the beans to do is add heat. The art of roast- will start to ‘yellow’ and this is signi- will start to change colour to a light ing is in how and when heat is ap- fying that they are absorbing heat; brown. This is a result of a complex plied. With careful monitoring of taking the energy it will need to fuel reaction between amino acids and ‘how fast the coffee is roasting’, important chemical reactions, and sugars within the coffee. The Mail- we can learn to tease out the fla- starting to shed moisture from it’s lard reaction can also be observed vours we love in coffee and avoid surface even at this early stage. when you make toast or seer a steak those we don’t. How much heat is applied at this As the browning continues, the sug- Luckily for us, we can monitor the stage and for how long will affect ars start to caramelise and produce visibly different colour stages of the the speed of our roast and have flavours that are often associated beans through the glass lid of the an effect on the Maillard reaction/ with coffee (think caramel, toffee, roaster. The colour changes gives browning. sugar, etc). These reactions also us a really good idea of what is start to create complexity in flavour happening to the coffee throughout It is typically not the stage that most and changes to the ‘body’ of the the roast. affects the flavour but, of course, coffee when it is brewed. you can make or break a roast We start with green beans entering here and it might be interesting to Again, there is no one-size-fits-all the roasting chamber, the very be- experiment with. recommendation on heat applica- ginning of the roast. The tempera- tion during this stage of the roast. ture of the beans at this stage is low Beware the tipping point! Applying Each coffee has its own special (room temperature). It’s therefore too much heat for too long this early ‘sweet spot’. Rather, it’s for you to really important we inject a lot of on can lead to a roast defect called note that important chemical reac- heat so we can properly build the “tipping”, which is where moisture tions are starting to take place and momentum of our roast. is released from parts of the surface have an impact on the end result. too quickly, causing ‘tips’ of burning Experimenting with altering time You’ll notice that all of our recom- that would still be visible after the and temperature points during the mended roast recipes begin in this roast has finished and would not be Malliard reaction, will give you the manner. That’s here that our profiles desirable in terms of flavour. best chance of making an impact differ the most from profiles you see before moving into an essential elsewhere. This is to do with the way phase: development. the temperature is measured, using the inlet temperature measured by the PT1000 sensor. We are beginning to roast green coffee - at room temperature: we need to begin with a big injection of heat so we can quickly move our raw beans to it’s first key stage: drying.

14 First crack and development with more body and are more suit- Cooling and degassing The best part of a roast! The cof- able for brewing espresso. Once our roast has finished, we want fee will audibly pop or crack like to cool the beans down as quickly as popcorn and puff up slightly. This Things are happening quickly here: possible in order to stop the chemi- is caused by a build up of steam even small changes in heat applica- cal reactions and any further devel- pressure inside the bean resulting tion and/or time can produce differ- opment past where we want to stop in moisture bursting through the ent flavours in the cup. How much the roast. weakest point. Now more than at development time and temperature any stage in the roast so far, the in- to apply is down to preference and Degassing is the process of allowing side of the bean is exposed to more this is a great opportunity to make Carbon Dioxide to escape from the heat. changes in the pursuit of finding dif- roasted coffee. Roasted coffee can ferent flavours. be set aside in a sealed container for We must be careful to not apply too 3-6 days before use. We have found much heat at this point. You may A quick note on second crack: we that coffee that has been roasted by observe that the red line on the will briefly cover roast colour shortly Convective heat can remain ‘fresh’ recommended recipe declines at but for now it’s important to know tasting for several weeks. How long this point, as less heat is necessary that if the roast continues long you leave coffee to degass is a mat- to progress the coffee through the enough, coffee will experience a ter of preference. You may even find roasting process. second crack. This is slightly softer it preferable to wait even longer sounding and it’s usually when oils than 3-6 days before using your Depending on how heat has been will begin to move from the inside of roasted coffee, depending on your applied before this stage, first crack the bean to the surface. brew method. will be quick and loud or slow and long. But regardless, it’s from this The coffee bean becomes quite We are now almost ready to look point that we could, if we wanted, brittle at this point. Second crack at changes to an IKAWA recipe in stop the roast and consume the cof- is a good marker for the point at a more practical way. Before we do fee. It’s also the point in the roast which the darker roast flavours can that, we want to introduce you to where the most flavour develop- dominate the inherent flavour of the some of the ways that ‘roast colour’ ment happens. coffee beans. Our recommended typically changes the flavour of your recipes tend to show terroir through coffee. Because of the importance in this being light-medium developed. stage, we often refer to ‘develop- That’s our own preference and ment time’ as a way to track how a there’s no right or wrong answer roast continues after 1st crack (i.e. when it comes to your own prefer- how it develops). ence!

Shorter development times generally have a bright profile,suitable for brewing filter coffee. Longer and darker roasts tend to be less acidic

15 Principles of roast colours

The colour of roasted coffee will Light Roasts Medium Roasts change depending on the heat ap- Also referred to as “city roast”, they Also called “full city”, the medium plied during the key stages of a are usually more mottled on the out- roast lives between the end of first roast. The colour to which the coffee side of the bea, resembling wood crack and the beginning of second is roasted, depends on your prefer- grain. A good light roast is sweet crack. ences. The colour also indicates the with lots of bright acidity or spar- flavours that may be present. kle and features the inherent origin A good medium roast will highlight characteristics of the coffee. the unique flavours within a coffee On one end, you could roast ‘light’, and have a complimentary body risk under-developing the coffee or You will achieve a lighter roast and sweetness. You will also start you could find that sweet spot to re- through less heat application and to taste some of the roast flavours ally highlight the coffee’s inherent a shorter development time ,with in the cup (see the darker colours in characteristics. Or you could have roasts finishing shortly after first our recommended flavour resource a more balanced approach by add- crack. ‘Good’ flavours are hard to mentioned earlier). ing some typical ‘roast’ flavours, by achieve in ‘Light’ roasts: underde- going for a ‘medium’ colour. On the veloped coffees can easily taste The acidity or sparkle will be lower other end, you could achieve the vegetal, sour, and weak. than a light roast. Generally, the ‘dark’ levels of ‘roast’ flavours, but sweet spot for a medium roast is if you push it even further, you will Often, a higher amount of heat appli- larger than it is for a light roast; eventually get ashy/smoky flavours. cation at the beginning of a roast is meaning you have more wiggle beneficial to developing any coffee room to produce different, great Let’s take a quick overview of the and especially lighter roasts. Lighter tasting coffee and you usually have options here and then introduce you roasts are aiming to showcase the more flexibility when brewing. to a useful way to think about roast terroir, variety and processing of the ‘degree’ and flavours. coffee. Developed properly, lighter roasts can make for amazing cups of unique flavoured coffees.

16 Dark Roasts Typically roasts that go past second crack. These roasts have very re- duced acidity and unique flavours. The body tends to be full and the beans are very soluble when brewing. Roast flavour is dominant which can produce flavours that are smok- ey or ashy in flavour.

This isn’t to say that all dark roasts are bad - a good dark roast of the right green coffee is enjoyable. It can be dense and sweet with enough acidity to cut through and balance the coffee. However, like a light roast, the balance is fine and a dark roast is usually easier to get wrong than right.

17 How to find your perfect roast level

We recommend experimenting with Great job for getting this far! It’s your turn to experiment differing roast levels to find what you Use one recipe,recommended for either generally prefer. Now that you have the knowledge and filter or espresso and roast green coffee basic principles of the Ikawa Home without changing the recipe. As you get used to changing recipes at roaster, you are empowered to make different stages in the roast, you will start changes to those recommended recipes, Then, move one of the points on the to notice what causes a shift in this area. turning those recipes into your own. red line, changing the coffee to make it It’s important to remember to approach more towards your liking. Whether that’s any changes in a recipe empirically: We hope that this document has been a darker roast or a fruitier taste, always helpful for you to learn more about how note what you wanted to achieve and Change one point at a time and observe your Roaster works, a brief theory of how you went about doing it. how that one change altered how the Green Coffee and roasting, and the logic coffee moved through the roast cycle, behind how the recipes work. It is now You will now have two roasts to compare i.e. how did the speed of the coffee time to put it all to practice! to each other. You can repeat the second change? step multiple times, for multiple roasts, Now armed with this information, we to see how they compare to the original Our recommended recipes are just the want you to pick a recipe to make even recipe a. beginning of your experience. better! When we say even better, it means to tweak the coffee more to your Once the tweak is done, please roast personal preference. the coffee, allow 3-6 days to degas and compare.

18 19 Contact us:

Emily Jackson - Coffee and Content [email protected]

Charlie Hauben - Content and Communications [email protected]

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