Apart from different types of roasters or methods, here, the primary focus will be to help you understand the roasting process and apply this information in any way you choose. 

Why Consider Roasting Your Own Coffee At Home?

A simple answer to this question is that roasting coffee beans yourself means you have full control over the freshness of your coffee, resulting in the fullest taste and guaranteeing the quality of each cup.

The taste difference between a home roasted cup of coffee and one you have bought at a local coffee shop can be worlds apart. 

Roasting raw coffee beans at home is also much easier than you might think and can take between five-to-fifteen minutes depending on your chosen method.

The financial savings you can make by roasting coffee at home, as opposed to paying regular visits to expensive coffee shop chains, especially if you consume a lot, can be significant.

The equipment needed to start roasting at home can also be purchased very cheaply, making home roasting a wise choice, economically speaking.

Finally, it is also a fun hobby, trying different methods and techniques to achieve varying results, and trialling different beans to discover your favourites.

Why is it better to use a roasting machine? 

Using a special instrument initially constructed for roasting coffee, you’re most likely going to get an even roast. 

Since the roasting machine has a mix of airflow with convective and conductive heat transfer, it’s a great tool for roasting coffee beans from both inside and outside.

If you want to try a homemade alternative roasting method, this can also work but requires proper knowledge. 

How to Roast Coffee Beans in the Oven?

  • Preheat your oven to 500 degrees F, or its full temperature.
  • Spread the beans evenly in the steamer or perforated pan and put that on the cookie sheet.
  • Check the beans every minute or two.
  • Keep moving them from side to side for even roast.
  • Within 5 minutes, you’ll get the first crack. Now, watch them for your personalized color.
  • NOTE: Lots of smoke will be released when you open the door.
  • Place the beans into metal colander to release the chaff and cool them.
At least you can make a fresh cup of joe for the fire brigade

How to Roast Coffee Beans on the Stove?

  • Preheat the pan on the stove (set it somewhere between medium-high). And pour a measured quantity of green beans.
  • You can use the perforated lid to entrap the heat inside the pan and save your kitchen from a mess caused by chaff.
  • Shake the pan every 20-30 seconds for even roasting. Roast until you get your desired color.
  • TIP: Keep your beans between the first and second crack
  • Separate the chaff from the beans and cool them by gently swirling the colander. Give ‘em rest before enjoying.
Mix the beans constantly to avoid scorching

Weight Your Beans

Before any roast, you need to weigh out the beans accurately. When you’re done with the roast, weigh the beans again. These two numbers are significant to calculate the percentage of weight lost during the roasting process.  

This way, you would be able to compare your results with the last roast or to plan your next roast more precisely.

Stages of Roasting Coffee

Here are main roasting stages you should know as a beginning home roaster:

  1. Beans’ Drying Phase. In this phase, the beans stay green and move around, building up some temperature. 
  2. Yellowing. Then comes the yellowing phase, where you’ll see this very distinct yellow color.
  3. Browning. Beans turn brown and look like coffee but still, they are very light. Once the internal temperature reaches high enough, all the moisture inside the beans tries to break out, and now the beans hit their first crack.
  4. First Crack. You’ll start hearing the cracks one after another. After some time, they pick up momentum, and the cracks start moving along. At this point, a crescendo builds up, and it slowly tapers off, just like a bag of popcorn in your microwave.
  5. Beans Reach the Lull Phase. After that first crack, next is a brief period in between, which is nice and quiet; that’s called the lull. If you continue roasting after this lull, you’re going to hit the second crack.
  6. Second Crack. Not as strong as the first one, but you’ll definitely still hear the sound. Here, you’ve reached the dark roasting territory.

It’s vital to know different sounds and stages to learn coffee roasting so that you can stop roasting at the light, medium, or dark level, depending on your preference. 

How Far Should You Go When Roasting Beans? 

This is a crucial question on how far you should go to get a light, a medium, or a dark roast. But keep in mind, these are not defined points; instead, all are spectrums

Coffee Roasting Stages

Light roast is just a stage that happens, likewise to medium and dark. But there are some simple signs to acknowledge which will help you get to the preferred stage. 

For Light Roasted Beans

For a light roast, remember that the first crack builds momentum to reach a peak and then starts to taper off. So after that peak and still with continuous first crack, this is a great time to stop roasting your coffee for a light version. 

You can’t stop earlier until you reach this point. Even though your coffee is drinkable after the first crack, taking the coffee up to the peak is the best practice to get nice coffee. 

Now, see whether it needs a little more or less time for the next batch.

From Light to Medium Roast

You have to go through the first crack for a medium roast and wait unless there’s silence. So once the first crack is wholly finished and a moment before the second crack, you’ve accomplished the medium roast. 

Now, you can go for a bit too dark in the very least time when you’re at this point. So, you should stop it right there as soon as the first crack stops. And put your beans to get cool. This will be a really lovely medium roast. 

From Medium to Dark Roast

If you want to make dark roasted coffee, you have to understand that things progress very quickly at this stage of the roast. And at that right moment, 15 seconds can make a huge difference in your coffee. So you need to be very careful and vigilant. 

Now, for darker coffee, you need to take your coffee up to the point that the second crack begins. You hear the first few pops of the second crack. And now, you need to stop the roast within the first 15 seconds of the second crack

Beyond that, it’ll get very dark quickly, so be attentive for the next 15 seconds. Decide now if you want a little more or a little less, but that’s a great place to aim for. 

Bonus Tip: Give a precise time to cool your coffee beans for best results. 

Why Cooling Period is Important

Once you’ve got your coffee roasted to the level you want, place the beans to cool. Right now, they have a high temperature, and if you don’t cool them efficiently, they will continue moving further along the roast. 

Sometimes, even though you’ve stopped roasting the beans at a nice medium roast, they would still have enough heat left in them that you would hear the second crack happening. So don’t make a rush. 

According to all the coffee experts in the world, it is best if you can cool your beans down to room temperature in four minutes or less. Some roasters wait for room temperature, while others prefer a very long cooling cycle that you shouldn’t be using.

How Can You Help Your Coffee Bean to Get Cool?

The one very easy way to do this is to take your beans, dump them out into a metal colander, and start shaking them around for a couple of minutes. Now, as you’re doing this, you’ll notice that a lot of the chaff is falling out from the colander. 

Chaff is a skin of green coffee beans, which release during the roasting process. If it ends up in your coffee, it’s fine. It’s tasteless and doesn’t matter if you grind it up and brew it.

Chaff can create a mess in the whole roasting process 

Allow the Coffee to Rest

After finishing the roasting, allow the coffee to rest for 24 to 48 hours before drinking it. Coffee usually reaches its optimum flavor between 3 to 7 days after roasting. 

Since the coffee goes through a process called off-gassing, let the coffee cool for the first 48 hours. During this time, CO2 is released from the roasted beans. The longer the cooling phase, the best the flavor of the coffee you can have. 

However, it’s perfectly okay to use your beans the same day you roast them, but the coffee will have more body and more flavor if you wait a couple of days.

Roast Defects

Achieving the perfect roast takes practice so you can develop your knowledge, easily identify defects, and control every aspect of the process. Some defects are much easier to spot than others, but an experienced coffee roaster identifies the tell-tale signs and adjusts their roast accordingly.

Photo credit: Loring.com
  • Baked Beans. A defect that can occur when the coffee has been roasted for too long but does not achieve cracking to release the flavour. The bad news is that this defect cannot be visibly seen and results in a dull, flat taste that can be likened to bread.
  • Underdevelopment. This can happen when attempting a light roast but falling short somewhat, therefore the sugar in the beans fails to caramelise, resulting in a flavour that is similar to that of grass or hay.
  • Overdevelopment. The opposite of underdevelopment and goes beyond a dark roast, resulting in beans that are very dark, almost black, and have an oily consistency. The final product is likely to have a burnt and bitter taste.
  • Scorching. A result of the charge temperature being too high and the drum speed not being quick enough. This leavesdark burn marks on the flat parts of the coffee beans (scorched), creating a smoky and oily taste.
  • Tipping. Quite similar to scorching, tipping sees burn marks appear on the edge of the bean, rather than the flat part. This commonly happens during the second crack of a roast and results in a similar burnt and unpleasant flavour.
  • Quakers. These are beans that have not sufficiently ripened and are not easy to spot when the green beans are inspected and sorted by hand. Poor soil condition is the main cause for unripened beans as they have not received enough sugar and starch. 
Tipping. Photo credit: Barista Hustle

How to Identify and Prevent Roast Defects

Assuming you want to avoid purchasing expensive equipment that is designed to analyse coffee roasts, measure the consistency and identify defects, then gaining experience and conducting your own analysis is the best way forward.

Creating a spreadsheet that details physical changes of coffee during a roast for future reference can be a clever way of identifying each defect and making the necessary adjustments. 

The chance of a batch of green coffee beans containing at least a couple of the defects stated above is unfortunately quite high due to the quantity of the beans. The good news is, that with more experience and knowledge, you can learn how to identify these defects and manage roasts to counter their impact.

Keep a Roasting Log As a Tracker

It would help if you kept a roasting log to record and calculate. Read further to understand this idea. 

TIP: You can use our roasting timer for this purpose.

There is a 200 grams bean (the initial weight), 166.6 is the ending weight, and the percentage of moisture loss is 16.7%

You note down the starting weight and subtract the ending weight from it. This gives you the difference here. With the difference rate, you divide it by the starting weight and get a decimal 0.167. Then you convert it to 16.7 percent. 

This percentage is super dark. Usually, 13.5% moisture loss or 14% is considered the right reach. However, it varies from variety to variety. 

The percentages are an excellent indicator for the next roast plus for comparing the before-and-after roast.

The first crack started within 5 minutes and 15 seconds into the roast. After that, the beans were placed to cool at 7 minutes and 35 seconds. So, the difference from the first crack to the drop was 2 minutes and 20 seconds. 

This information will help you make the beans a little bit darker or lighter next time according to your preferences.  

You can also get a Coffee Roast Log from 33books

Frequently Asked Questions

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