The Ultimate Roasters Guide For The Best Coffee Beans
What's better than learning how to roast coffee beans? It’s a rhetorical question because for us: Nothing beats learning how to buy coffee beans and roast at home.
Understanding the roasting process broadens your appreciation for the art and the science that goes into pouring the perfect cup of coffee. Home roasting also ensures that your coffee is as fresh as possible, and the roast is as light or dark as you prefer.
We’re strong advocates for home roasting - we love it! We’ve seen countless people intending to try it just once, only to become home roasting addicts. It’s a passion of lifelong learning with never ending surprises and satisfaction.
Enjoy the best tasting coffee in your home by following our simple guide. We cover the various methods, their pro’s and con’s and explore which one is best for you.
“What will I need to get started?”
The great thing about home roasting coffee beans is there’s virtually no barrier to entry. Depending on your chosen method and what you’ve already got at home you can get started roasting today!
The Preferred Methods to Roast at Home
Diving into the world of home roasting is incredibly easy. Choose the home roasting method you feel most comfortable with out of the following:
- Roast in a pan/grill
- Roast in an oven
- Roast in a popcorn machine
- Roast in a purpose-built home roasting machine
Roasting in a pan or oven is the cheapest way to get fresh beans.
But for producing the best possible results we recommend that you choose either a popcorn machine or a purpose built roasting machine for their simplicity and consistency.
However, the price jump from a popcorn machine to a coffee roasting machine can be massive.
Popcorn machines can be picked up brand new from as little as $20 whereas a high-quality home roasting machine can be around $500, skyrocketing upwards from there. Cheaper machines can be around $150 but are often of inferior quality and may break down sooner.
If you're serious about home roasting your coffee beans, it's worthwhile investing your money in a machine that will stand the test of time!
A Word of Caution
- Popcorn machines are designed for popcorn. Using a popcorn machine to roast coffee beans will void the warranty, and the machine may break after a few months of regular roasting. Additionally, not all popcorn machines are suited to roasting beans.
- Ensure your popcorn machine heats from the sides. DO NOT roast coffee beans in a machine that heats from the bottom! This will not only result in a weak and uneven roast, but the collection of chaff can ignite and cause house fires.
- Always clean out all chaff between roasts, and NEVER LEAVE YOUR POPCORN MACHINE UNATTENDED!
Buy a home roasting machine if it’s within your budget. Your resulting roast is often better than a popcorn machine, and these are purpose built so will usually last far longer than a popcorn machine ever will.
The one method we haven’t covered in this guide is microwave roasting...
It is possible to roast green beans this way, but the poor results and inconsistencies that come with it make it impossible for us to recommend this method. Use one of our four other methods if you’re going to roast coffee beans at home
The roasting process is simple, and if you follow our guide, you will be guaranteed a fantastic roast no matter your chosen method.
Understanding the Roasting Process
In this article, we’ve provided you with step-by-step instructions for each of the four home roasting methods. Your exact approach to roasting will vary depending on your chosen method.
But what never changes, is the roasting process:
- Beans get hot
- Beans get roasted
- Beans get cool
- Beans get delicious
It’s a simple process with some necessary steps to note along the way to guarantee great results. These important steps hold true for every roasting method.
Let's take a quick look at what happens during roasting, and after roasting, so that you know what's going on while the magic is happening:
Roasting
- Temperature: 350F to 500F is the widely accepted temperature range. This varies depending on the roasting method you’re using
- Agitation: Your beans can never rest and roast! Constant stirring ensures an even distribution of heat, and thus an even roast
- First Crack: After 3 to 5 minutes the beans will produce an audible crack.This crack indicates that your beans are lightly roasted and ideal for white coffee. This the minimum amount of time required to produce roasted beans. Continue roasting and agitating for darker roasts
- Second Crack: After a few more minutes another crack is heard. This second crack indicates a medium roast. A few more minutes of roasting and your beans will be burnt and unusable. Experiment with times to find your favourite roast
- Tip: We usually wait roughly 30 seconds after hearing the second crack
- Cool Down: Transfer beans to a metal colander or baking paper to cool. Use two metal colanders (plastic can melt). Shake and transfer your roasted beans between colanders. This cools the beans quickly and removes the chaff.
Spread evenly over baking paper to substitute for a metal colander. This method is not as effective - Remove Chaff: Chaff is the dried husk of the coffee bean. It is very messy. Cool your beans down outside or in the sink to reduce clean-up
Pro Tip: Collect the chaff and make cascara coffee
It is one of those things that you'll get the feel (and eye) for with practice. This video is a good start:
Post-Roast and Chemistry
When you’re roasting coffee beans, you are creating an awesome chemical transformation - the Maillard reaction.
Over 800 compounds are transformed from the boring, flavourless compounds present in the green bean into the delectably delicious and aromatic compounds found in roasted beans.
This is why green beans smell and taste nothing like roasted beans. The compounds in the green bean are waiting to be transformed!
Roasted beans release gas (CO2): This continues for weeks after roasting. Why should you care?
- CO2 helps to naturally preserve roasted beans by displacing oxygen
- Oxidation ruins beans. They become stale
- Too much CO2 in coffee beans creates too much crema (a bad thing)
- Not enough CO2 creates stale tasting coffee (also a bad thing)
De-Gas: Wait 12 hours before sealing in a container (Allow the initial Co2 to ‘de-gas’)
- Sealing newly roasted beans in storage too early will lead to CO2 pressurization. This can pop the top off your container potentially damaging it
- Coffee beans that contain too much CO2 will result in an undesirable flavor. Give your beans a chance to de-gas!
- Opinions differ. From a few hours to a few days. In our experience, we’ve found 12 hours to be a good rule of thumb. Your experience might prove otherwise - do what works for you
Grinding and Storing after Roasting
- Wait 24 Hours before you Grind & Brew. Beans need a day to mature and reach full bodied flavor
- Store in Airtight Container: Keep beans fresh and use within seven days
- Coffee is always best when it’s fresh. After more than one week, your roasted coffee beans will begin to turn stale as oxidation does its thing
- Read more info on storage at the end of this guide and see our article on storing beans for more tips and tricks
Getting Started
Alright – enough with the science side of things, you’re here to learn how to roast your own beans at home, so follow these steps and you’ll be roasting like a pro in no time…
Step 1: Buy Green Beans
It all starts with the beans, which technically speaking are seeds. Fresh beans are green. Once dried, they become several shades lighter. Once roasted they are completely transformed, becoming the beautiful and inviting rich shades of brown that we’re used to seeing.
Excellent coffee is all about consistency.
Choose green beans that are uniform in size and color. This ensures an even and consistent roast and flavor.
Getting these two elements correct - color and size - is vital to avoid producing coffee with an inconsistent and unfavorable flavor.
Step 2: Roasting
This is where the magic happens. Choose from one of the following four methods and follow our guide to producing the freshest, most delicious beans you’ve ever tasted!
We'll show you how to roast with a pan, an oven, a popcorn maker and a home roaster below.
Roasting Coffee in a Grill or Pan
Everyone has a pan or grill lying around, which means this method is very popular in the home roasting community.
You'll find plenty of how-to videos on YouTube, however, be weary of who you take advice from - many DIY roasters tend to overcook their beans using this method!
NOTE: Do not use a coated/non-stick pan. Doing so will negatively impact the flavor.
PROS
- Fast & convenient
- No need for additional purchases
CONS
- Difficult to get the correct temperature
- Very smoky
What You'll Need
- Green beans
- Thick pan (steel/uncoated)
- Hot plate/Grill (gas is preferred)
- Metal colander x 2
- Oven mitts
- Wooden spoon
- AIr-tight storage container
Method
- Maximise ventilation. Turn on the exhaust fan and open the windows. It’s going to get smoky and smelly (the good kind of smelly, the bad kind of smoky). Grilling outside is the preferred option to avoid overpowering your fellow occupants
- Place a thick pan on medium heat. Around 450F will normally do the trick
- Getting the temperature right the first time can be difficult. Experiment to find the best heat
- A gas stove/grill will make attaining and adjusting the temperature much easier
- Add a shallow layer of green beans to the pan. Enough so you can stir with ease
- Keep Stirring. Never let the beans rest. Ensure they’re heated evenly
- Listen for the first crack after 4-5 minutes. Your beans are now a light roast
- Listen for the second crack after 6-7 minutes. A few minutes later the beans will crack for a second time indicating a medium roast. Roasting for much longer will result in burnt beans. Most people, us included, will wait roughly 30 seconds after this second crack before removing from the heat
- Dump beans into metal colander. Stir and shake. Cool them down ASAP. Do this in the sink or outside to avoid the inevitable chaffy mess. Wear oven mitts! Everything will be very hot
- Leave beans exposed for 12 hours to de-gas
Roasting Coffee in the Oven
Another popular DIY home roasting method involves your oven, but be warned: you'll need ventilation as it will get smoky!
NOTE: If your oven is the kind that blows a gale, do not use it. The chaff will get blown around leaving you with a great chaffy mess to clean up.
PROS
- No need for additional purchases
CONS
- Slower than other roasting methods
- Difficult to get a perfect roast
- Very smoky
What You'll Need
- Green beans
- Perforated oven tray (regular trays will also work)
- An oven
- Metal colander x 2
- Oven mitts
- Air-tight storage container
Method
- Preheat oven 500F: Crank it up to 11. Temperature will vary for different beans and different ovens. Start at 500F and experiment up and down from here to find what works for you
- Open everything but the oven door: Things are going to get smoky. Maximize ventilation
- Spread green beans over a perforated tray: One layer deep only. Do not stack them!
- A perforated tray will produce the best results. Just make sure that the tray you’re using doesn’t allow beans to slip between the holes
- Beans expand during roasting and will get stuck in any holes that are large enough to accommodate a green bean
- Don’t have a perforated tray? Try your luck with a regular oven tray and place a sheet of baking paper under the beans. Give them a shake or two as they roast
- Place on tray on middle shelf: The middle of the oven provides the most consistent temperature
- Listen for the first crack after 5-7 minutes: Your beans are now lightly roasted. Roasting for much longer will result in burnt beans.
- Listen for the second crack: The beans are now a medium roast. Most people, us included, will wait roughly 60 seconds after this second crack before taking out of the oven
- Transfer to a metal colander. Stir and Shake: Cool them down ASAP. Do this in the sink or outside to avoid the inevitable chaffy mess. Wear oven mitts the whole time
- Leave beans exposed for 12 hours to de-gas
Roasting Coffee in a Popcorn Machine
Popcorn machines are made from popcorn. Certain types, however, will do a great job at roasting coffee beans. Just make sure you read our safety concerns about roasting with a popcorn machine before getting started.
NOTE: You must use a machine with side vented heat to avoid burning and to ensure rotation.
PROS
- Simple
- Automatically agitate/rotate beans
- Easy to get a perfect roast
CONS
- Not built for roasting coffee
- Some machines will break after a few roasts
- Price is not an indication of the longevity of machines used for roasting
What You'll Need
- Green beans
- Popcorn machine with side vented heat
- Wooden spoon
- Metal colander x 2
- Oven mitts
- Air-tight storage container
Method
- Ventilate! Roast near an open window, or outside, if possible, to avoid filling your house with smokes and smells
- Pre-heat machine. 30 seconds, depending on the model
- Measure ½ cup of green beans. Plonk into the machine. Ensure the beans can rotate
- Popcorn machines should agitate the beans. If there’s no agitation you’ve probably filled the machine too full
- Using the same quantity of beans as the machines’ recommended quantity of corn kernels is a great starting point
- Assist the agitation. Use a wooden spoon and encourage the beans to start moving
- One you’ve got some consistent movement place the lid on
- Keep an eye on this for the whole roast and lend a helping hand if you must
- Use the handle if your spoon is too big
- Collect chaff in a large bowl. Catch all the chaff that will come out of the machine’s spout. As soon as the lid is back on get your bowl in position to avoid a massive clean-up
- Listen for the first crack 3-5 minutes. You’ve achieved a light roast!
- Listen for the second crack 6-8 minutes. Medium roast attained! Keep roasting for another 30 - 60 seconds to get a darker roast. Much longer and your beans will begin to burn
- Transfer between colanders to cool the beans. Use oven mitts when handling the machine and colanders. Things are going to be sweltering. Do this outside or over your sink to avoid a chaffy mess
- Allow 12 hours for the beans to de-gas
Roasting Coffee in a Coffee Roasting Machine
PROS
- Purpose built and long lasting
- Simple to use and clean
CONS
- More expensive than other options
- Bulkier than other options
What You'll Need
- Green beans
- Coffee roasting machine
- Oven mitts
- Optional: Metal colander x 2
Method
- Ventilation. All roasting methods, including roasting machines, will produce lots of smoke
- Turn the machine on. Add green beans. Follow the manufacturer's instructions. Machines are similar, but requirements differ
- Monitor the entire roasting process. Many machines will claim full automation. However, with all of the variables (bean size/type, ambient temperature, age of machine, etc.) roasting times can still vary
- Listen for the first and second cracks. The first crack indicates a light roast. The second indicates a medium roast. Finish roasting once the beans have reached your desired roast
- Transfer between colanders to cool the beans: Your machine may have it’s own cooling process. If not, cool them down ASAP
- Do this in the sink or outside to avoid the inevitable chaffy mess.
- Wear oven mitts for this process
- Allow 12 hours for the beans to de-gas
Step 3: Storing home roasted beans
When you buy pre-roasted beans, you’ll notice a little valve on the outside of the bag. This is a one-way valve that allows the built up CO2 to vent without letting oxygen in. This keeps the beans fresher for longer.
There are storage solutions that you can buy that employ the same one-way valve system. There’s even high-tech solutions that pressurize the container with an inert gas!
Regardless of your storage solution; space age or stone age, it needs to be airtight. It also must be kept cool and in the dark to ensure the flavors are preserved for as long as possible.
For something, a little different check out the wall mounted Zevro Indispensable SmartSpace Dry-Food Dispenser (below) that promises to be airtight and delivers roughly 1 ounce per turn.
There’s also the vacuum sealed Alpha Coffee Canister (below) that promises a 100% money back lifetime guarantee. The only thing to remember is that taking advantage of its features will require you to seal it after each time you use your beans.
Fancy storage solutions are all well and good, and they may help to extend the life of your home roasted beans by a few more days. However, you can avoid purchasing anything extra simply by repurposing an old mason jar.
And if you haven’t got anything fit for purpose, grab something cheap like the stainless steel Friis 16-Ounce Coffee Vault:
Regardless of how you end up storing your beans just remember:
- Airtight
- Opaque/Solid
- Keep it Cool
VERDICT - Should You Roast Your Own Coffee Beans Home?
If you ask us, the answer is unequivocal yes.
It’s not just a fun and rewarding experience, but it’s the only way to guarantee the freshest, tastiest beans while ensuring that you’re always drinking the roast you prefer: light, medium or dark - the choice is yours.
With virtually zero barriers to entry, you can begin home roasting with whatever you already own, or make a few small purchases to get up and running. And now you know how to roast coffee beans from the comfort of your humble abode.
Buying pre-roasted beans is still an excellent option. But with a little time and a small amount of effort you can begin drinking the best coffee you’ve ever had!
What’s more, home roasted coffee beans make an ideal gift for your coffee loving friends and family, providing they love coffee as much as you do.
So what do you think? Are you going to give home roasting a go? Have you already tried? Leave us a comment and share your experiences. If you’ve followed our guide, we’d love to hear how you went.
