Roasting your own coffee is one of the best ways to enjoy it. When you roast coffee at home, you guarantee that every cup of coffee you make will be fresh and, with a little practice, you can ensure that it is roasted exactly to your taste.
If you want to drink great coffee, you can either go to a coffee shop or roast the beans yourself. Roasting your own beans lets you control the quality of your coffee from start to finish.
To roast coffee at home, you need a few supplies and green coffee beans. It is important to understand the entire process from start to finish so that you can better understand how your roasting can impact the flavors of your coffee.
Dark or Light, Slow or Fast?
Many people refer to the roast level of a bean in terms of its final color or how long it takes to achieve that color. Even though two coffee beans may look similar if they are both lightly roasted, they can taste different depending on the roasting conditions.
During the roasting process, a large number of chemical reactions take place. One of which is moisture evaporation which reduces weight. A slow roast can lead to greater weight loss than quicker roasting. High quality coffee is often produced from slow roasts, even though they may be costly.
The goal when roasting is to establish a balance between sweetness, bitterness, and acidity. In general, coffee’s acidity will be reduced if it is roasted for a longer time than usual. If a roast takes a long time, the coffee will have a stronger, more bitter taste.
What Happens During the Coffee Roasting Process?
Green coffee changes drastically during the roasting process. When you roast coffee, the water inside the bean is forced out, making the bean itself dryer and larger.
Some of the natural sugars are converted into CO2 gas and others are caramelized into flavors that help form the complex flavors in coffee during the brewing process. The green beans will transform into brown beans that are 50 to 100% larger, and 18% lighter.
The coffee’s flavor and aromas begin to degrade soon after the roasting process is complete.
Roasting Stages
There are many important steps during the roasting process, and the conditions under which beans reach these steps is known as a “roast profile.” Most roasters have their profiles carefully tracked, allowing them to replicate roasting within very specific boundaries by controlling time and temperature.
Drying/Green
Raw coffee beans contain 7-11% water by weight, evenly distributed throughout the bean. The coffee won’t brown if there is water present.
The roaster needs to be loaded with coffee and left to absorb heat so it can start to evaporate the water and dry out. After the first three minutes of roasting there are few to no changes in smell or appearance.
Yellowing
When water is no longer being released from the leaves, browning reactions start to occur. During this stage, coffee beans have a fragrance similar to that of basmati rice. When the beans start to expand, the thin, papery skins, also known as chaff, begin to flake off. The chaff is separated from the roasting beans by air that flows through the roaster. The chaff is then collected and removed safely to prevent the risk of fire.
The first couple of roasting stages are important for evenly roasting the coffee beans. If the coffee beans are not dried properly, then they will not roast evenly during the subsequence stages. The exterior of the beans will be roasted, but the inside will be undercooked. The coffee will taste bad because it will be bitter and sour. If your coffee starts to roast unevenly, slowing down the roasting process won’t help since different parts of the coffee will continue to roast at different rates.
First Crack
After browning reactions have started, water vapor and gas build up within the bean. The majority of this gas is carbon dioxide. The pressure inside the bean builds until it becomes too much and the bean pops open, increasing in size by about double. Coffee flavors then begin to develop.
Roasters will notice that coffee temperatures will decrease, even though they might be adding heat. This happens when the coffee is over-roasted and the heat needs to be reduced. The result: a low-quality cup of coffee.
Roasting Development
After the beans crack, their surface will become somewhat smoother. This part of the roasting stage sets the bean’s final color and how dark it will be roasted.
As roasters assess the balance of bitterness and acidity, they determine when to end the roast. The roast is happening/taking place, the acids inside the beans are degrading quickly, and the bitterness level is increasing.
Second Crack
Beans start to crack with a snappier noise. At the second crack, oils are forced out of the bean to the surface. When coffee is roasted, much of its acidity is lost, developing a different, sometimes referred to as a generic, “roast” flavor. This flavor is not caused by the type of coffee used, but by burning or charring it, which affects the coffee’s natural flavors.
Some terms are used for darker coffee roasts, such as “Italian roast” or “French roast.” These terms suggest significantly darker roasts that are both generally high in bitterness and body. The original characteristics of raw coffee are almost all lost.
Quenching
The roast needs to be quickly cooled to stop the roasting process and prevent negative flavors from developing. When roasting in small batches, this is usually accomplished by cooling the coffee down quickly with cooling trays that draw air rapidly.
When roasting large batches of coffee, spraying the coffee with water mist can help it to cool down more quickly. The beans release heat as the steam evaporates. If this process is done correctly, it won’t have any effect on the quality, but it may shorten the shelf life slightly. Many companies artificially increase their “supply” of beans by adding a surplus of water to make them heavier. Not only does this harm the quality of the coffee, it is also morally wrong.
Dark Roast Vs. Light Roast
People have different preferences on how dark they like their coffee beans roasted, but they may not know all the roast levels by name. The main types of coffee roasts are Light, Medium, Medium-Dark, and Dark.
The roasting process for Full City and Full City Plus dark roasts should be the same because they are both dark roasts. There are certainly differences between roasting coffee for a City roast and a French roast.
As beans roast, their internal temperature rises. And with that rising temperature, different considerations come into play. There are different types of roasts that are distinguished by the internal temperature of the beans when they are removed. Therefore, let’s examine how hot the beans need to be in order to achieve the desired roast.
Light Roast
If you want a light roast, you should aim for an internal temperature of 356-401°F. The light roasts have a light body and acidity with a toasty, sometimes grainy flavor. Common light roasts include: light city, half city, and cinnamon roast. No matter what you call them, they usually fall during the first crack. At this point, the beans are dry on the outside, and they may be hard to bite into (especially if they are removed before reaching the first crack).
This type of roast is best if you like your coffee with more acidity or “brightness” and a light body. This roast is also less risky to do at home, as it needs less time and a cooler temperature.
Medium Roast
The ideal temperature range for medium roasts, including city and city+, is 410-428°F. The beans will be less green and more dry than the original beans. This roast level is achieved when the coffee beans make a cracking sound during the roasting process, typically around the middle to end of the first crack. Other people believe that only coffee beans roasted until right before second crack should be called a medium roast.
Roasts at this level are more popular than light roasts, because they have more mid-level acidity and a fuller body. Plus, the temperature is still manageable for most people.
Medium-Dark Roast
This category includes Full-City, Full-City+, and sometimes Vienna Roast. But it is smaller in terms of temperature window. Medium-dark roasts reach temperatures between 437°F- 446°F. You may notice patches of oil on the beans as they approach 2nd crack.
At this point, the flavors of the roast become more notable, alongside the differentiating flavors of the coffee, creating hints of spice and a more full-bodied taste.
Dark Roast
Lastly, coffee that is labeled as French Roast, Italian Roast, or Espresso Roast is considered to be dark roast. They roast the beans at 464 degrees Fahrenheit, but the most important rule is to keep the temperature below 482 degrees Fahrenheit. This text is talking about how things can go wrong if you don’t have the right equipment. These beans have an oily surface and low acidity. They are pulled out during the 2nd crack.
When it comes to flavor, roast character is often considered more important than origin character. If you’re looking to roast your coffee beans to a darker color, be extra careful as you approach the point where the beans start to burn.
Roasting Coffee at Home
Since the middle of the 20th century, many people have purchased coffee beans and roasted them at home. Roasting your own coffee at home is a fun and inexpensive way to get great tasting coffee, but it can be difficult to achieve the same quality as coffee from a commercial roaster.
The key advantage to roasting your own coffee at home is the ability to produce small batches. This way, you can experiment with a range of different green coffee varieties. You can expect to be both surprised and disappointed during this journey – instead of thinking of it as a way to save money by roasting your own beans, treat it like a fun hobby. It is probably not worth the effort if it feels like a tedious task.
More and more companies are selling green coffee online. You should not buy raw coffee in large quantities even though it lasts longer than roasted coffee. Raw coffee degrades over time and doesn’t taste as good.
Here are a couple tips for selecting a green coffee:
Make sure that you can find out where your coffee beans come from before you buy them. Many green coffees on the market are of poor quality and not worth purchasing.
A company that sells roasted coffee is a good place to buy green beans. This will allow you to compare your roasted beans to commercial ones and track your progress.
3 Things You Need to Roast Your Own Coffee at Home
You will need a few supplies to help you perform the roast properly:
Green Coffee – Depending on where you live this could be the most difficult part of your roasting process. Investigate whether any coffee shops in your area sell unroasted coffee beans, or if there are any local roasters who do.
Different types of roasters can be used to roast coffee beans, including a simple popcorn maker. A few roasting methods are highlighted below, along with the type of roaster that is best suited for each.
Storage – Once you roast your coffee, you will need a place to store it until you use it. Remember, the more air tight the better. Even the best container won’t be able to keep the coffee’s flavor and aroma from dissipating after about a week if it isn’t used.
Is Roasting Your Own Coffee Worth It?
If you’re mostly concerned about coffee freshness, then roasting your own beans is a good idea. There is a short time frame in which coffee beans are the freshest, and roasting your own beans guarantees that you get to enjoy all the delicious flavor characteristics while they are at their best. The beans will start to lose their flavor over time.
Don’t feel like doing the roasting? A good alternative that doesn’t involve leaving your house is to subscribe to a coffee service where the beans are roasted fresh and shipped out immediately.