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


You can even go down seriously to 50% capacity or lower for sample roasting and profiling. However, this will mean you have to modify the method by which you roast as you have a lot more space in the drum.


Altogether, this mean's that it's vital that you have a balanced approach when deciding on the size of your roaster; too big could be just as detrimental as too small coffee bean roaster machine. For more insight, and to break down roasters right into a few different size categories, I spoke to Neil Maree from Genio Roasters in Johannesburg, South Africa. Continue reading to find out what he said.


Picking The Right Size Is Important
Neil says that at Genio, customers are often unaware of the facts they have to consider when investing in a new roaster. “People often ask for the absolutely wrong size, or they inquire about the price of our roasters,” he says. “To me, this points to a lack of knowledge and understanding about both their target market and their power to sell.


He says that while people often look for larger roasters as a way of ensuring they have the capability to expand, it's not too simple. “Lots of people have think they have to get a large roaster in order to turn a profit. These people believe they want a huge machine simply to roast coffee for the area community.


“Ultimately, upscaling your operation is easy, as long as you have a buyer for the coffee. Being able to roast 5,000kg of coffee doesn't mean as possible sell 5,000kg. Begin 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 searching for smaller machines. Neil says: “On the other end, we've got those who think that they'll obtain a 1kg roaster and take up a business from it.


“It will take 15 minutes to roast a group on a 1kg roaster, that will sell for maybe US $30. To be able to make a salary as a small business owner with this, you'd need certainly to stand behind the equipment for the entire day,” he explains. “This leaves you no time for you to sell! Roasting doesn't equal making money. Selling equals making money.


To illustrate enough time cost for using roasters of certain sizes, Neil compiled a couple of models and forecasts for roasters of different skill levels that you will 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 an example roaster is to judge samples of a particular coffee when 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 alone ideal for anyone looking to take up a roastery at a sizable scale.


There's also plenty of overlap between craft and sample roasting at this range; many home roasters will naturally stick 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 thing up for roasting coffee at almost any commercial scale is just 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 best roast profile for a new coffee.


They're a great selection for micro-roasters, as well as successful coffee shops looking to roast their particular beans. Most coffee shops don't sell significantly more than 10kg of coffee in one day, but even should they do get close, a 1kg to 3kg roaster will have a way to deliver that in a matter of hours.


For a café or perhaps a smaller existing coffee business, this is a good place to start. By starting small and being strategic about simply how much coffee you roast, you are able to build-up a wholesale customer base steadily with no risky overheads of a more costly roaster.


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


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


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


However, it's also important to notice that your consistency will naturally decrease as you start roasting a better quantity of batches. Like, 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 would have an 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 worthy of teams looking to roast coffee at scale as opposed to small businesses or cafés looking to diversify.


“A Genio 6 roaster can roast up to two tonnes of coffee a month,” Neil tells me. “That's plenty of coffee.” He notes, however, that regardless of this potential output, smaller-capacity commercial roasters remain quite versatile and can still be used to roast tiny 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 on a monthly basis,” he says. “It is certainly possible, but you'd have to have a mechanic regularly carry out an important service on your own car.”


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


Medium Commercial Roaster (15kg to 30kg)
Machines with a group size of around 15kg are most worthy of existing roasting businesses that have a good base of customers. Many successful specialty coffee roasters will find that this is actually the biggest machine they'll ever need.


Neil notes that numerous roasters believe it is tempting to sell their preexisting roaster to finance a costly purchase, but warns against it. He says that he often sees this when people arrive at him to purchase larger roasters, such as the Genio 15 or the Genio 30.


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


Large Commercial Roaster (30kg to 70kg)
Moving after dark 15kg to 30kg bracket will only be necessary when you have an enormous customer base. Roasters of this size are likely to be operating on a sizable commercial scale.


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


“[With these bigger roasters], people often don't have the best gas supply or ventilation in place,” he says. “It could be just too difficult to perform a chimney from the premises or a gas main in… at this size, it is 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 specific size of one's space to consider. As many roasters start a small scale and gradually scale up, their premises can often only fit a few small machines. At this stage, it may be required to relocate.


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


Similar to the previous size category, roasters will also need to think about the physical constraints of the space before installing a piece of equipment of this size. These roasters will often be found 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 tells me that as well as space on the floor, ventilation, and gas supply, additionally you need to consider machine maintenance if you're upgrading to a bigger machine. Bigger roasters take more effort to clean and could be more complicated to maintain.


Changing the size of your roaster will even 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 through the roast.


Be prepared to need certainly to tweak and change. “You can't truly copy profiles from one roaster to the other, although we do head to extensive efforts as manufacturers to try and make that easier,” Neil says.


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