What is Coffee Roasting?
Coffee Roasting is the process in which you bring out the flavour and aroma in raw green coffee beans. It is achieved with heat and turns the coffee beans from green to brown.
How does Coffee Roasting Work?
Using a high temperature the green beans are roasted, this causes a chemical reaction. When at optimum taste and flavour the now brown coffee beans are cooled to bring the process to a halt.
Coffee roasting is not as simple as it may sound, there is a skill involved, one that can be learnt over time which is what makes it a pass time and hobby. You will have to develop a skill that allows you to determine when the roasted bean is at optimum flavour and aroma. It all boils down to a split second window, roast too much or not enough and your whole batch can be ruined.
Where do Coffee Beans Come From?
There are two types of coffee plant, the Arabica or the Robusta, both come from the seeds of berries, which means your coffee beans start their life as fruit. The difference between Arabica and Robusta can be found here.
The berries are left to become ripe, they are then picked, processed and dried out.
Coffee plants and their fruit are grown and cultivated in more than 70 countries worldwide but primarily they are grown in the equatorial parts of The Americas, India, Africa and South-East Asia.
Stages of Coffee Roasting
With an incredible, 800 different types of flavours and aromas, roast coffee actually only has four main, basic types of roast.
Light Roast Coffee
Simply put a light roast coffee is roasted for the shortest period of time, absorbing the least amount of heat of all 4 types of coffee roast. Light roasted coffee is of a light brown colour and usually are not roasted beyond what they call the first crack.
The first crack is where the beans expand and crack when they get to around 350 degrees Fahrenheit.
In regards to flavour, light roast coffee beans taste almost acidic and earthy. They contain the highest amount of caffeine because the more a coffee bean is roasted the more caffeine is burnt off.
Some of the familiar names you may have heard of in the light roast coffee category are Cinnamon roast, half & light city and New England roast.
Medium Roast Coffee
In the USA the medium roast coffee is probably the most popular with the highest sales. With a medium brown colour and a non-oily surface, the medium brown cup is full of flavour and traditional. At around 410 degrees Fahrenheit the medium roast coffee is complete just before the second crack.
As they are heated for a longer period of time the amount of caffeine medium roast contains is less than light roast.
Some familiar types of Medium Roast Coffee are City, American and Breakfast.
Medium/Dark Roast Coffee
Medium roasted coffees have a little amount of oil on the surface and are a medium brown colour. The flavour is almost spicy and aromas are noticeable.
Medium Roast coffees are achieved at the beginning of the second crack at around 225 degrees Fahrenheit.
They contain more caffeine than Dark Roast but less than light or medium roasts.
Some popular coffees in the medium to a dark roast category are After dinner and Vienna.
Dark Roast Coffee
Dark Roast can appear almost black and are very dark in appearance. The dark roast coffee is heated for the most time of all coffee types and contains the least amount of caffeine.
Dark Roast Coffee is often used in espresso and can taste rather smokey and bitter, they may also have a charcoal flavour to them.
Heated to around 465 degrees Fahrenheit and beyond the second crack is when dark roast coffee is ready.
Popular types of dark roasts include Espresso, Spanish, Italian and French.
What Equipment do I need for Coffee Roasting?
The best thing about taking up coffee roasting as a hobby is the minimal amount of equipment you will need to get started, you can do it even when working with a very small budget.
- Unroasted Green Coffee Beans (mandatory) – You will NEED to purchase unroasted green coffee beans in their raw state, a good rule of thumb is to buy double the amount of green coffee beans according to the amount of roasted coffee you want to produce. So for example to produce a pound of roasted coffee you will need to purchase 2 pounds of unroasted beans. My favorite raw coffee beans
- Skillet (budget method choice) – Using a skillet is a difficult method but a good option to those of you working with a budget, all you will need is a good quality cast iron skillet. We found a fantastic skillet on Amazon for a bargain price with thousands of positive reviews (Check Price on Amazon)
- Popcorn popper (budget method choice) – Yes, you read that right, a popcorn popper. Not just for popping popcorn so it seems. Also a very good way of roasting coffee, you can’t just use any old one though. To roast coffee at home with a popcorn maker It will need to be a hot air and open top, that allows you access to the coffee beans while roasting so you can stir them. The Hamilton Beach Hot Air Popcorn Maker is often used for roasting coffee and has received very positive reviews.
- Oven (budget choice) – You can use your oven but this is probably the most difficult way to carry out the roasting process.
- Hot Air Roaster (best choice) – Hot air coffee roasters are by far the most simple method of roasting coffee beans, you simply add your raw coffee beans and press a button. Voila, the whole roasting process is automated. Kind of takes the fun out of the home coffee roasting process, that being said you’ll end up with your perfect roast coffee each time. Check out the FreshRoast SR500, we’ve written a little more about further down this guide.
- Metal Colander
- Oven Tray
- Airtight container – For storing your roasted coffee beans in once they have been roasted to your preference, the airtight container should be stored in a cool dark place to ensure they last for the maximum amount of time.
- Digital Scales – Digital scales or normal scales are perfect for weighing out the correct amount of raw coffee beans before adding them to be roasted.
How to roast coffee at home
There are several methods you can choose from when roasting coffee beans depending on the equipment you have, some are more straightforward and simple than others.
I have taken the 4 most popular home coffee roasting methods and explained step by step “how to” with each.
Method 1 – Roasting Coffee at home using the oven
Before you try this method you should know that of all the roast coffee methods this is the least popular, and the least effective/successful.
The beans will not be as evenly roasted as other methods and the flavours are often not as desired.
It really is a method of trial and error and the type and standard of your oven will play a huge part in your final product.
That being said it’s a method you can try straight away without the need to purchase any more equipment.
- Firstly you should preheat the oven to around 450 degrees Fahrenheit.
- While waiting on the oven to reach optimal temperature, lay your raw beans out on the pan, ensure they are even and cover the whole pan without overlapping each other. You will need a pan that has numerous small holes with a slight lip to keep the beans in the pan, I use a vegetable steamer basket.
- Once the oven is at the correct temperature place the pan of beans onto the centre shelf/rack in the oven.
- Leave the coffee beans for about 15 to 20 minutes and at this point, you should start to hear a crackling and popping noise (first crack)
- If you want a more dark roast then you should continue to roast, remember to stir the beans around a little every few minutes to ensure an even roast.
- When you have reached your preferred roast you should put on your mitts and remove the pan from the heat immediately.
- Pour them directly into a colander, take a second colander and empty them back and forth into each other. If you haven’t got a colander then you can pour them onto a tray with cookie sheeting and slide them around for a while. This part helps the bean aerate and removes residue.
Method 2 – Roasting Coffee Using a Skillet
For this method, you can either use a large cast iron pan or skillet.
For the best possible taste ensure that the pan is clean before use as you don’t want the coffee flavour tainted by last nights dinner.
- Place the pan or onto the stove/hob. Bring the temperature of the pan to around 450 degrees Fahrenheit or less if you are wanting to achieve a lighter roast. At this point, it’s a good idea to have a thermometer to check the temperature.
- Once you are at this temperature you can add the raw green coffee beans. Only add a maximum of 8oz of beans. Stirring at this point is very important if you want to roast the beans evenly. You will need to manually stir with a spoon or spatula as there is a much higher chance of burning the bean.
- At around the 4 minutes mark, sometimes longer you will hear a popping or crackling sound coming from the pan, the beans are now at the start of the roast. The beans will also produce a coffee scented smoke that is really strong. Depending on how you want your roast, light to dark it is an important time now for you to watch.
- Check the colour of the coffee beans regularly, when you have achieved the roast you desire it’s time to pour them out onto a metal colander. You will need to continue to stir the beans until they have cooled.
- Once the beans have cooled remove them and put them in an airtight container and store them in a dark and cool location.
Method 3 – Roasting Coffee Using a coffee air roaster
Using a coffee air roaster really does take all of the complications out of it, it makes things as simple as selecting your preference, pressing a button and hey presto perfect roasted coffee beans.
As I previously mentioned I personally own the Freshroast SR500 and I haven’t got a bad thing to say about it.
- Measure out your coffee beans into the coffee roaster.
- Press the pre-set setting that you want to use for your personal preference of roast coffee.
- Once the roasting time has passed you can choose to press a button for an extra cooling cycle if you wish.
- Now remove your roasted coffee beans and place them into a storage container for later use.
That is really how simple it is once you have a coffee air roaster, if you are not confident in doing things more manually but want to have the perfect roasted coffee beans then this is your best option.
It may cost more to buy but it makes the process so simple and will save you lots of time in the long run.
Method 4 – Roasting Coffee with a popcorn popper
A very popular home method, however, before I explain how you can achieve roasted coffee with a popcorn maker I need to make you aware of a couple of things.
Using a popcorn popper for roasting coffee with almost definitely void any warranties you may have with the products this is because you are using it beyond its intended use.
There also is a possible risk of fire. So use this method at your own risk.
- Switch on your popcorn popper and let it warm up for approximately 30 seconds, then quickly add around half a cup of raw coffee beans. (Max amount will be when the popcorn popper barely rotates the beans)
- Leave the lid off the popcorn popper for now and begin to stir the coffee bean inside, once the beans inside start rotating more easily you can then add the lid.
- Soon you will start to see the silver skin of the coffee appearing from the chute, this should have taken place around 2 and a half minutes into the process.
- At around 4 minutes the bean should hit the first crack and you will start to hear crackling from the popcorn maker. You are now at the light roast stage of your coffee if that is what you want to produce (skip to 7) if not continue.
- After another minute or so a different type of crack can be heard, it should be more muted but higher pitch than the first crack. You are now at the second crack stage or medium roast. If this is the roast you desire you should stop now (skip to 7) if not you can continue.
- I only usually take it to around 30 seconds from the second crack and have never really let it go much further as this is my own preference, however, should you want a darker roast then leave for another minute after the second crack I would suggest. You should be able to observe the bean and tell.
- Switch off the popcorn popper, put on your mitts or gloves, and pour out your coffee into your colander (Warning the coffee is extremely hot)
- Take a second colander and pour the roasted coffee beans between the two of them, back and forth, this will aerate the coffee beans. (If you don’t have colanders you can use a tray with cookie sheeting and slide the beans around)
Best Coffee Roasting Machine
There aren’t many coffee roasting machines available on the market, well at least not good ones anyway.
The coffee machine we are going to discuss is a fantastic price and has received great feedback.
FreshRoast SR500 Automatic Coffee Roaster
- Very Simple to use, perfect for beginners.
- Clear container so you can visually check your coffee bean preference.
- Chaff and oil collection.
- 90 grams of raw beans capacity which yields around 78 grams of roasted.
- Manual stirring or select high fan for even roasts.
- Quietest air roaster; Great visibility; Very simple to use; Chaff collection; Durable; Small footprint; cooling cycle
With over 300 positive reviews the Freshroast SR500 is the perfect beginners coffee roasting machine.
You can fully automate the roasting process and yield perfect roasted coffee to your preference every time.
The default setting is around 6 minutes which will give you a light roast all you have to do is press a button to add 6 seconds to the timer. You can press as many times as you like until your roast coffee is as you like it!
I love that the chaff cleaner is located on the top of the machine making it super easy to clean.
Remember guys when you are roasting coffee with the SR500 to ensure you have ventilation, roasted coffee beans can give off quite a strong unpleasant odour while roasting.
You can grab this coffee roaster for a great price
(Check Price & Reviews for the Freshroast SR500 on Amazon)
How to store your Roasted Coffee Beans
Once you have your roasted coffee beans you’re going to want to store them correctly so you keep the flavour and freshness locked in, this part is very important.
The moment the coffee beans are roasted they will start to lose flavour and aroma. This is down to heat, light, air and moisture.
To keep all of the flavours locked into the roasted coffee beans for the maximum amount of time you should keep them sealed in an airtight container at room temperature.
I recommend keeping them away from light and heat. So you will need to find a nice cool and dark place like a cupboard away from the oven or other heat sources.
Here’s a perfect airtight opaque container for storage (Check Price on Amazon)
Home Coffee Roasting Tips
- Disable smoke alarms and open windows if you are roasting coffee beans, but remember to turn the smoke alarm on afterwards. Roasting coffee will produce a lot of smoke!
- If you are roasting coffee beans in a skillet or pan then invest in a thermometer, a candy making thermometer will be perfect.
- The darker the roast the less caffeine the roasted beans will contain.
- Continuously check the colour of the beans and listen for the sounds to ensure you get your optimal preference for roast coffee.
- Be careful going beyond the second crack this is when the bean will start to burn.
- Always clean any equipment you use to roast your coffee afterwards removing all of the skin and residue (known as chaff)
- Try different methods for a different amount of time until you find your favorite roast bean.
- Some new popcorn makers have a built-in cut off which won’t allow them to go beyond a certain temperature these can’t be used to roast coffee.
- If you are using a popcorn popper to roast coffee beans then opt for one that allows you to stir the beans so they do not burn.
- Store the roasted coffee beans for about 3-4 days before using them. This is to allow the levels of carbon dioxide and nitrogen gasses to decrease, to avoid a metallic flavor.
- Use a quality green bean, before you become an expert coffee roaster you will need to find quality ingredients.
Home coffee roasting is fairly simple to achieve and a great inexpensive hobby and pass time!
Primarily it’s all about preference and finding the right roast for you, this is achieved by experimenting and practice.
There are many more resources available on the internet if you want to take your roasting to another level, but in the meantime, we hope this beginners guide to coffee roasting has been helpful and got you started!
If you can think of anything we have missed or perhaps have a question to ask then please leave a comment below and we will be sure to get back to you!
Coffee Roasting FAQ
How long does it take to roast coffee?
The length of time taken to roast coffee depends on what type of roast you are wanting to create from light to dark roast.
The darker the roast the more time it takes to roast coffee. It also depends on how you are roasting the coffee and what method you are using.
How long do the roasted coffee beans keep?
If you have followed my storage advice above and kept them in an opaque and airtight container in a cool and dark place then on average the beans will last around 3 weeks.
That being said if you are very careful with storage you may find your beans will last up to 6 weeks.
The beans can last longer, however, after time they will start to change or lose their flavor.
Can you roast coffee without a machine?
Yes, you certainly can you don’t need to invest in an expensive automated machine to roast coffee you can choose to use a skillet or the oven in the kitchen! These methods though are much harder to grasp, making it harder to get the perfect roast.
Can you re-roast coffee beans?
It is possible to re-roast coffee beans but I would strongly advise against it, the flavor will not be nice and you’ll end up with a kitchen full of smoke!