Most manufacturers recommend that roasters don't make use of a machine at full capacity. As an over-all rule, they recommend using about 75% of the listed capacity (depending on the manufacturer) allowing for consistent airflow through the roast.

You may also go down seriously to 50% capacity or lower for sample roasting and profiling. However, doing this will mean you've to adjust the method by which you roast as you've a whole lot more space in the drum.

Altogether, this mean's that it's crucial that you take a balanced approach when selecting how big is your roaster; too large could be just like 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 learn what he said.

Picking The Right Size Is Important
Neil says that at Genio, clients are often unaware of the facts they need to consider when buying a new roaster. “People often request the completely wrong size, or they ask about the price tag on all of our roasters,” he says. “If you ask me, this points to deficiencies in knowledge and understanding about both their target market and their ability to sell.

He says that while people often look for larger roasters as a way of ensuring they've the ability to expand, it's not too simple. “Plenty of folks have think they have to get a large roaster to be able to turn a profit. These individuals think that they want a huge machine merely to roast coffee for the neighborhood community.

“Ultimately, upscaling your operation is straightforward, so long as you've a customer for the coffee. Being able to roast 5,000kg of coffee doesn't mean that you can sell 5,000kg. Start with selling 1kg, then 100kg, and then 500kg, and so on,” Neil explains. “Often, we find ourselves convincing visitors to go for smaller machines.

However, this doesn't mean there aren't mistakes among people trying to find smaller machines. Neil says: “On another end, we've got individuals who think that they can buy a 1kg roaster and take up a business from it.

“It will take 15 minutes to roast a batch on a 1kg roaster, that may 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 starting a coffee roastery. “This leaves you no time and energy to sell! Roasting doesn't 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 will find here.

Sizes & Categories
For the purposes with 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)
Since the name suggests, the key focus of a sample roaster is to judge types of a certain coffee before you commit to purchasing large volumes of it.

While you will find exclusive and high-quality coffee roasted in small batches on sample roasters, they are not by yourself ideal for anyone trying to take up a roastery at a sizable scale.

There is also a lot of overlap between craft and sample roasting at this range; many home roasters will naturally adhere to a low minimum capacity if they're 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 type of commercial scale is just a small batch roaster. These range in proportions from 1kg to around 3kg and are good for sample roasting in larger batches or identifying the proper roast profile for a new coffee.

They're a good option for micro-roasters, as well as successful coffee shops trying to roast their particular beans. Most coffee shops don't sell a lot more than 10kg of coffee in a day, but even should they do get close, a 1kg to 3kg roaster will have the ability to deliver that in a matter of hours.

For a café or even 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 minus the risky overheads of a more costly roaster.

Neil informs me that this was the target market for Genio's smallest machine, the Genio 3 Micro Coffee Roaster, launching in December 2020. “With this particular, we wanted to target on people who have been ‘owner-operators '; one or two-person businesses who roast and sell on their own,” he says.

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

Small batch roasters likewise have their uses for larger roasteries, however. Many will keep a machine with 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 begin roasting at scale.

However, it is also important to notice your consistency will naturally decrease as you start roasting a greater amount of batches. For instance, 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 deficiencies in consistency may have a direct effect on customer retention.

Small Commercial Roaster (5kg to 15kg)
Commercial non-small batch roasters start at around 5kg. The next phase up from a small batch roaster, these machines are more suitable for teams trying to roast coffee at scale as opposed to small businesses or cafés trying to diversify.

“A Genio 6 roaster can roast up to two tonnes of coffee per month,” Neil tells me. “That's a lot of coffee.” He notes, however, that regardless of this potential output, smaller-capacity commercial roasters remain quite versatile and can still be utilized to roast really 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 similar to driving 5,000 miles each month,” he says. “It is certainly possible, but you'd have to have a mechanic regularly carry out an important service in your car.”

Finally, Neil notes a roaster with this size is just a significant investment. For a lot of up-and-coming roasters, he warns a larger roaster might be bigger than the business needs. “Even although you can roast two tonnes of coffee per month, you will need to consider: who are you currently going to sell this coffee to?

Medium Commercial Roaster (15kg to 30kg)
Machines with a batch size of around 15kg are most suitable for existing roasting businesses that already have a good base of customers. Many successful specialty coffee roasters will discover that here is the biggest machine they will ever need.

Neil notes that numerous roasters think it is 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've a 6kg roaster and you want to buy a larger roaster. I'd claim that you shouldn't sell the 6kg roaster – which should become your backup. Mechanical faults do happen – things break.” At this point, by having an established customer base, being left without a roaster might be catastrophic.

Large Commercial Roaster (30kg to 70kg)
Moving past the 15kg to 30kg bracket is only going to be necessary if you have a huge customer base. Roasters with this size are apt to be operating on a sizable commercial scale.

However, at this stage, you can find apt to be unforeseen expenses that come along with the purchase of a bigger roaster, as Neil explains.

“[With these bigger roasters], people often don't have the proper gas supply or ventilation in position,” he says. “Maybe it's just too difficult to perform a chimney out from 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 personally to be sure our larger products can match your space.”

Beyond ventilation and gas supply, you might also need the particular size of your space to consider. As much roasters start on a small scale and gradually scale up, their premises can often only fit several small machines. Only at that stage, it could be necessary to relocate.

Extra Large Commercial Roaster (70kg and up)
Beyond 70kg, extra large commercial roasters are often used for mass roasted coffee as opposed to high-scoring specialty coffee. Operating a machine with this size will need a passionate team, and it will probably be used to deliver a steady, signature flavour profile on an extensive scale as opposed to roasting different single origin lots, for example.

Just like the last size category, roasters will also have to think about the physical constraints of these space before installing a machine with this size. These roasters will often be present in large open manufacturing spaces, as they could require 50 to 60 square metres of space and often weigh over two tonnes.

Other Points To Consider
Neil informs me that as well as living area, ventilation, and gas supply, in addition you need to consider machine maintenance if you're upgrading to a bigger machine. Bigger roasters take more effort to completely clean and could be more complicated to maintain.

Changing how big is your roaster will also affect the profiles you've identified for roasting certain coffees. While these existing profiles can still be utilized as a baseline, understand that machines of different sizes will act differently through the roast.

Anticipate to have to tweak and change. “You can't truly copy profiles from roaster to another, even though we do head to extensive efforts as manufacturers to use and make that easier,” Neil says.

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