What’s So Great About Air-Roasting Coffee?

If you want to start a spirited debate among a group of coffee roasters, simply pose the question, “To air-roast or drum-roast? Which is better? And...discuss.” Then, grab some popcorn, sit back, and enjoy the show.

Drum-roasting has been around since the advent of roasting coffee, so when new coffee roasting methods like air-roasting (aka fluid-bed roasting) are introduced to disrupt the status quo, it’s human nature to want to compare and deem one method superior.

And, ever since coffee industry maverick and chemical engineer Michael Sivetz introduced the Sivetz Roaster in the early 1970s — using hot air instead of a hot surface to roast coffee beans — this is exactly what’s been happening. 

Folks, that’s practically 50 years of conversation! And, it’s only gotten more heated (pun intended) in the last decade as specialty coffee has gone more mainstream. Internet-trained, home-brewing roasters are trending, causing many coffee lovers to value coffee even more for the specialty commodity it is instead of just the black stuff that wakes them up.

In the end, it’s a debate that has no clear-cut winner since — even though there are some clear-cut factors worth considering — it really comes down to subjective taste. And, as much as we might like it to be so, you can’t measure taste with a simple calculation or formula. 

As coffee aficionados in the coffee roasting equipment and roastery development business, we have a deep appreciation for both coffee roasting methods. We’re proud to offer a wide variety of new and used coffee roasters — including air roasting options like Sivetz, Coffee Crafters and Sonofresco — and a broad selection of drum roasters.

We plan to introduce more air roasting choices in the near future, so we thought it would be useful to devote blog space to air roasting’s attributes that might make it a coffee-roasting contender in your roastery or cafe. 

And, spoiler alert: In case you’re tempted to scroll to the end to see where we weigh in on air vs. drum roasting, just know that we leave the final verdict up to you. We do discuss drum roasting in the next section, but this is not a straight comparison, either-or, this-or-that article. 

Heck, we honestly can’t even present drum roasting as one thing to compare air roasting against. There are so many factors and decisions that affect a final drum-roasted product, from the green beans you start with, to the type of drum and heat transfer, roasting time, batch size, preferred roasting profile, and so forth.

At the end of the day, we simply want to provide what we think are some main attributes that could make air roasting a good choice for you. And, if that’s the path you decide to go down, then we’ve got some great options to get you started. 

To Better Understand Air-Roasting Coffee, First A Short Departure

There are good reasons why drum-roasting is attractive far beyond the quality of the coffee roast. To start, there’s no denying that drum-roasting brings out the art and craft of this time-honored process. 

Think of a cook who spends the day in their kitchen, pouring loving care into their culinary creations. It’s all about the tinkering, the tweaking, the tasting. The cook can immerse themselves in the process, believing that all of their care and attention infuses itself into the finished product. 

Add to this that drum roasters are big, beautiful roasting beasts with a certain “Old World” charm. If you’re going to be roasting all day, it’s nice to feel good about your roaster. And, if you feature your roaster as a centerpiece in your roastery or shop, you know that its aesthetic appeal can draw customer interest.

But then we have the air roaster, and it definitely brings some strong attributes to the table that are well worth considering in our modern-day world. Let’s consider five reasons why air-roasting is worth a look.

5 Reasons to Consider Air-Roasting

Short Roasting Time = High Productivity

A standard air roaster can roast a batch of green coffee beans in as little as 6-8 minutes, at least half the amount of time as a traditional drum roaster. This short roasting time reduces the formation of negative acidic compounds that can make coffee taste bitter or cause stomach irritation. This is one reason why air-roasted beans are thought to have a more pure flavor than drum-roasted beans.

 

A Clean, Quality Product from Clean Machinery

Similar to a popcorn popper, a hot air roaster keeps coffee beans moving with a perfectly controlled hot airflow to produce an even roast. And, the hot air forces out the chaff — as well as other contaminants — that might otherwise burn into the beans and mask the true flavor profile of the bean. In short, the only thing being roasted is the bean. The end result can be a low-carcinogenic coffee product that many coffee lovers claim tastes clean and smooth.

 

Consistent Bean Temperature and Degree of Roast = High Reproducibility

A big benefit of an air roaster is the ability to accurately sense the digital bean temperature with a thermocouple. With this information, the degree of roast is known at all times, and you can easily adjust the settings for different degrees of roast and offer accurate reproducibility. The coffee “puffs” a bit more, the appearance is more even and attractive, and the roasts are very repeatable. 

With any product you offer, it’s important to be able to consistently replicate it. Your brand depends on it. An air roaster may just be the tool to help you do that.

 

Affordable

Air roasters can be an inexpensive way to get started in roasting. They’re a fraction of the cost of drum roasters, but you’ll need to remember that the smaller price tag also comes with a smaller batch size than drum roaster capacities. Still, with more air roaster options coming to market, you can produce a good amount of coffee in an 8-hour workday:

• The 1 kilo/2 lb Sonofresco roaster can produce up to 55 pounds of retail-ready coffee in an 8-hour period (6-7 lbs/hr)
• The Coffee Crafters Artisan 3-e coffee roaster can produce up to 144 pounds in 8 hrs (18 lbs/hr)
• The Coffee Crafters Artisan X-e can produce up to 480 pounds in 8 hrs (50-60 lbs/hr)

Simple Design = Easy Use & Maintenance

Simply put, with air roasters, you’re essentially looking at a “plug and play” option. Just install with common tools and you’re pretty much ready to go. No gas, no vents, no permits. With no smoke or particulate exhaust, this means no additional ventilation, afterburner, or chaff collector are required — making for a smaller environmental footprint. And, with a smaller physical footprint, an air roaster can be placed almost anywhere. 

Air roasters are designed with an intuitive interface that is quick to understand and easy to train your team to use. They’re also usually made of commercial-quality parts that are easy to clean and maintain. As with any machine you invest in, upkeep is important. To keep your air roaster operating well, you’ll need to monitor airflow rate and pressure:

Airflow Rate

The airflow always has to be fast enough to move the coffee beans around. It also controls how quickly heat transfers to your beans. Otherwise, they sit on the airflow inlet at the bottom of the roast chamber. The result is constant exposure to super-hot air, which makes them scorch and eventually ignite.

Airflow Pressure
Air roasters require a high-pressure flow of air. In drum roasters, the air has a lot of space to flow as it goes through the beans. In air roasters, the air has to physically lift the coffee to get through. This means that air roasters require blowers that can deliver high pressure. And, high-pressure systems are prone to leaks, which can cause smoke and loss of energy. So, this will be something to watch out for. If your air roaster appears to be lagging, identifying a leak is a good first place to troubleshoot.

Final Thoughts on Air-Roasting

At CoffeeTec, we believe that all good roasters (both equipment and people) can produce good cups of coffee. As with any venture or craft, it takes dedication, attention to detail, persistence, and passion to create a final product that your customers love and come back to again and again. 

Since the Sivetz fluid-bed roaster burst onto the coffee roasting scene about 50 years ago, new air roaster manufacturers have refined the equipment to offer roasteries and cafes an option that: (1) allows for time-efficient, productive roasting; (2) delivers a clean, quality, reproducible product; and (3) is affordable, and easy to use and maintain.

These benefits are leading more coffee roasters to believe that air-roasting is where the future of commercial coffee roasting is headed. We’re excited to see how the air roaster market continues to develop and grow!

In any case, we offer a couple pieces of advice:

• No matter which roasting method you choose, it’s true that you need to start with a good green coffee product to have a chance of getting a quality product out of it.
  
  
• As we’ve written before, coffee roasting is equal parts art and science. It’s a high-touch (and taste) business, so make your tools work for you but never let the tools replace your senses and care for the coffee-roasting process.

Have Additional Questions?

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Perhaps you’re interested in financing or are considering the option and benefits of buying used. We’ve got you covered for both. Finally, feel free to explore our FAQs, and if you still don’t have answers to your questions, contact us. Let’s help you build the coffee roastery of your dreams!