Whether you’re setting up a new roastery or upgrading your equipment, finding the right roaster can be daunting. As well as considering the space and budget you have available, you need to be mindful of the volumes of coffee you will be roasting on a regular basis.

Most manufacturers recommend that roasters don’t use a machine at full capacity. As a general rule, they recommend using about 75% of the listed capacity (depending on the manufacturer) to allow for consistent airflow through the roast.

You can even go down to 50% capacity or lower for sample roasting and profiling. However, doing so will mean you have to adjust the way in which you roast as you have much more space in the drum. 

Altogether, this mean’s that it’s important to take a balanced approach when deciding on the size of your roaster; too big can be just as detrimental as too small. For more insight, and to break down roasters into a few different size categories, I spoke to Neil Maree from Genio Roasters in Johannesburg, South Africa. Read on to find out what he said.  

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Picking The Right Size Is Important

Neil says that at Genio, customers are often unaware of the details they need to consider when buying a new roaster. “People often ask for the completely wrong size, or they ask about the price of all of our roasters,” he says. “To me, this points to a lack of knowledge and understanding about both their target market and their ability to sell.”

He says that while people often seek out larger roasters as a way of ensuring that they have the capacity to expand, it’s not that simple. “A lot of people have think they have to go for a large roaster in order to turn a profit. These people think that they need a giant machine just to roast coffee for the local community. 

“Ultimately, upscaling your operation is simple, as long as you have a buyer for the coffee. Being able to roast 5,000kg of coffee does not mean that you can sell 5,000kg. Start by selling 1kg, then 100kg, and then 500kg, and so on,” Neil explains. “Often, we find ourselves convincing people to go for smaller machines.”

However, this doesn’t mean there aren’t mistakes among people looking for smaller machines. Neil says: “On the other end, we’ve got people who think that they can buy a 1kg roaster and start a business from it.  

“It takes 15 minutes to roast a batch on a 1kg roaster, which will sell for maybe US $30. In order to make a salary as a business owner with that, you’d have to stand behind the machine for the entire day,” he explains. “This leaves you no time to sell! Roasting does not equal making money. Selling equals making money.”

To illustrate the time cost for using roasters of certain sizes, Neil compiled a set of models and forecasts for roasters of different skill levels that you can find here.

Sizes & Categories

For the purposes of this list, we’ve broken down commercial coffee roasters into six main categories by capacity: sample, small batch, small commercial, medium commercial, large commercial, and extra large commercial.

Sample Roaster (50g to 500g)

As the name suggests, the main focus of a sample roaster is to evaluate samples of a certain coffee before you commit to buying large volumes of it. 

While you can find exclusive and high-quality coffee roasted in small batches on sample roasters, they are not alone suitable for anyone looking to start a roastery at a large scale.

There is also a lot of overlap between craft and sample roasting at this range; many home roasters will naturally stick to a low minimum capacity if they are roasting coffee to solely be enjoyed at home. 

Small Batch Roaster (1kg to 3kg)

After sample roasters, the next step up for roasting coffee at any kind of commercial scale is a small batch roaster. These range in size from 1kg to around 3kg and are great for sample roasting in larger batches or identifying the right roast profile for a new coffee. 

These are a great option for micro roasters, as well as successful coffee shops looking to roast their own beans. Most coffee shops don’t sell more than 10kg of coffee in a day, but even if they do get close, a 1kg to 3kg roaster will be able to deliver that in a matter of hours.

For a café or a smaller existing coffee business, this is a good place to start. By starting small and being strategic about how much coffee you roast, you can build up a wholesale customer base steadily without the risky overheads of a more expensive roaster. 

Neil tells me that this was the target market for Genio’s smallest machine, the Genio 3 Micro Coffee Roaster, launching in December 2020. “With this, we wanted to focus on people who were ‘owner operators’; one or two-person businesses who roast and sell by themselves,” he says. 

“A 3kg roaster is the backbone of the owner-operated roasting industry.  You have enough capacity to really grow with a low enough capital outlay to be accessible to anyone with some savings and a passion for business.”

Small batch roasters also have their uses for larger roasteries, however. Many will keep a machine of this size on-hand to profile new coffees without wasting large quantities of fresh green coffee. These profiles can then be translated onto larger commercial machines to start roasting at scale.

However, it’s also important to note that your consistency will naturally decrease as you start roasting a greater number of batches. For example, roasting 600 batches in a 1kg machine will leave more room for error than, say, roasting 100 batches on a 6kg machine. Keep in mind that a lack of consistency could have an impact on customer retention.

Small Commercial Roaster (5kg to 15kg)

Commercial non-small batch roasters start at around 5kg. The next step up from a small batch roaster, these machines are more suited to teams looking to roast coffee at scale rather than small businesses or cafés looking to diversify.

“A 6kg roaster can roast up to two tonnes of coffee a month,” Neil tells me. “That’s a lot of coffee.” He notes, however, that despite this potential output, smaller-capacity commercial roasters are still quite versatile and can still be used to roast very small batches for profiling. 

Neil also warns against roasting to a machine’s maximum weekly or monthly output. “Roasting two tonnes of coffee on a 6kg machine is like driving 5,000 miles every month,” he says. “It is certainly possible, but you’d need to have a mechanic regularly carry out a major service on your car.”

Finally, Neil notes that a roaster of this size is a significant investment. For many up-and-coming roasters, he warns that a larger roaster could be bigger than the business needs. “Even if you can roast two tonnes of coffee a month, you need to think: who are you going to sell this coffee to?”

Medium Commercial Roaster (15kg to 30kg)

Machines with a batch size of around 15kg are most suited to existing roasting businesses that already have a solid base of customers. Many successful specialty coffee roasters will find that this is the biggest machine they will ever need.

Neil notes that many roasters find it tempting to sell their preexisting roaster to finance an expensive purchase, but warns against it. He says that he often sees this when people come to him to buy larger roasters, such as the Genio 15 or the Genio 30.

“Let’s say you have a 6kg roaster and you want to buy a larger roaster. I would say that you shouldn’t sell the 6kg roaster – that should become your backup. Mechanical faults do happen – things break.” At this point, with an established customer base, being left without a roaster could be catastrophic. 

Large Commercial Roaster (30kg to 70kg)

Moving past the 15kg to 30kg bracket will only be necessary when you have a huge customer base. Roasters of this size are likely to be operating on a large commercial scale.

However, at this stage, there are likely to be unforeseen expenses that come along with the purchase of a larger roaster, as Neil explains. 

“[With these bigger roasters], people often don’t have the right gas supply or ventilation in place,” he says. “It could be just too difficult to run a chimney out of the premises or a gas main in… at this size, it’s a significant consideration.

“At Genio, we offer pre-inspection through video calls or in person to make sure our larger products can fit into your space.”

Beyond ventilation and gas supply, you also have the actual size of your space to consider. As many roasters start on a small scale and gradually scale up, their premises can often only fit a few small machines. At this stage, it may be necessary to relocate.

Extra Large Commercial Roaster (70kg and up)

Beyond 70kg, extra large commercial roasters are generally used for mass roasted coffee rather than high-scoring specialty coffee. Operating a machine of this size will require a dedicated team, and it will likely be used to deliver a consistent, signature flavour profile on a wide scale rather than roasting different single origin lots, for example. 

Much like the previous size category, roasters will also have to consider the physical constraints of their space before installing a piece of equipment of this size. These roasters will often be found in large open manufacturing spaces, as they may require 50 to 60 square metres of space and often weigh over two tonnes. 

Other Points To Consider

Neil tells me that as well as floor space, ventilation, and gas supply, you also need to consider machine maintenance if you’re upgrading to a larger machine. Bigger roasters take more effort to clean and can be more complex to maintain. 

Changing the size of your roaster will also affect the profiles you have identified for roasting certain coffees. While these existing profiles can still be used as a baseline, remember that machines of different sizes will act differently during the roast. 

Be prepared to have to tweak and change. “You can’t truly copy profiles from one roaster to the other, even though we do go to extensive efforts as manufacturers to try and make that easier,” Neil says. 

However, Neil says that the time it takes to reach a certain roast profile shouldn’t really change as the size of your machine does. “Your roasting technique should not be determined by the machine,” he says. “It should be determined by the flavour profile of the coffee. But your machine must be capable of achieving these results.

“Let’s say that a bean will roast to its desired level in twelve minutes… [all good roasters] should be capable of reaching those target temperatures by that time, irrespective of the size of the machine.”

Whether you’re considering roasting coffee on the bar at your coffee shop or looking to expand the capacity of your existing roastery, there are a whole range of machines of different sizes out there to choose from.

However, as this article illustrates, choosing a roaster isn’t just as simple as figuring out how much coffee you can roast with it. Before you invest in a new roaster, ask yourself: what are your aims as a business? Do you have a sufficient market for the volume of coffee you’re planning to roast? And does that size of roaster really suit you?

Found this interesting? Don’t forget to check out How Can Roasters Build Good Relationships With Producers?

Photo credits: Genio Roasters

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