What is a color sorter machine for coffee?

For most roasters, the second half of 2024 was marked by one thing above all else: an unprecedented increase in the C price. Just over four years ago, coffee was trading just above $1 per pound – but in that short span of time, prices have increased by more than 200%.

With such a sharp increase in operating costs for roasters, there remains a need for roasters to navigate price volatility carefully in 2025. In a recent blog post, we outlined how automation can help roasters work more efficiently, giving them more time to focus on what matters – including sales and marketing. However, there are other factors to consider – such as how volatility in the C market can mean farmers focus on quantity over quality when exporting—leading to an increase in defects.

This is why roasters should invest in color sorter machines for coffee. They allow roasters to quickly sort out defective beans – rather than checking them by hand. And with innovation in the market, it’s now easier to find more precise equipment than ever. Ultimately, it means roasters can save time and money – as well as guaranteeing the quality standards their customers expect.

To learn more, I spoke to Jet Honderich, Head Roaster at Onyx Coffee Lab in Arkansas. We spoke about color sorter machines, and how they’ve used SOVDA’s Pearl Mini at their roastery. Read on to find out what he said.

What is a coffee color sorter machine?

Also known as an optical sorter, a color sorter machine identifies defective beans in batches of coffee. It uses two optical cameras to identify beans of the correct color, highlighting defects.

It then separates inadequate beans using pressurized air – all in the course of a few minutes. This allows roasters to automate their production line and focus on what really matters – increasing sales and growing their business.

Which defects can color sorter machines identify?

A color sorter machine for coffee eliminates defects that can ruin entire batches of coffee. These may include defects in the green coffee itself, as well as roasting errors. These include:

●      Insect damage: Pests such as the coffee berry borer can burrow minute holes into beans. The impact on coffee quality depends but can range from a muted flavor to outwardly sour notes.

●      Quakers: These are underripe, smaller beans with lower densities. They don’t have enough sugars to develop properly during the roast. Quakers can be caused by poor plant nutrition, bad picking practices, drought, or coffee leaf rust (la roya). Quakers are hard to spot until they are roasted, when they develop much more slowly and come out with a lighter color. This results in dry, papery, or cereal notes in the final cup. 

●      Burnt beans: Burnt beans are caused by a roast defect. This can be either “scorching” (where the charge temperature of the roaster drum is too hot) or “tipping” (when the airflow in the drum is limited and the beans don’t roast evenly). Ultimately, this causes ashen and burnt flavors in a batch of coffee after it’s roasted.

●      Black beans: Green coffee can turn black for a number of reasons. That might be nutritional deficiencies, fungal diseases, or over-fermentation. Either way, they can taste phenolic, fishy, or extremely fermented.

●      Broken beans: Green or roasted beans can break at any time throughout processing. Breakage can signify poor moisture content or under-ripe cherries – and can make beans more susceptible to mold. Batches with many cracked beans will roast poorly due to uneven heat transfer, resulting in an unbalanced, inconsistent flavor profile.

●      Patio/stones: When green coffee is dried on a patio rather than in a rotary dryer, it’s possible for stones or grit to be exported along with the beans. These can damage your equipment.

Why are coffee bean color sorter machines necessary?

Minimizing defects in green and roasted coffee is crucial for specialty coffee roasters. This is because the Specialty Coffee Association’s green coffee standards state that defective coffee is by its nature not specialty.

“For a coffee to even be considered specialty grade, the green must have zero primary defects and five or [fewer] secondary defects per 350 grams,” Jet explains. “Defects such as quakers and scorched or tipped beans can negatively affect the overall flavor experience.”

While you can manually sort coffee beans, color sorter machines are both more consistent and quicker. This means they streamline roastery operations – which is more important than ever against a backdrop of rising coffee prices.

At SOVDA, we’ve been designing equipment to support global specialty coffee roasteries since 2017. This includes weigh-and-fill systems, packaging machines, and color sorter machines for coffee. The Pearl Mini color sorter – which Jet uses daily at Onyx – accurately identifies and removes defects using two optical cameras and 64 air-splash valves. It is also designed exclusively for specialty coffee roasters.

It has a sorting capacity of 250kg of roasted coffee per hour and 500kg of green coffee per hour – helping to increase operational efficiency. After loading beans into the color sorter machine, roasters can easily navigate its user-friendly interface and smart operation features.

Onyx Coffee Lab’s Jet Honderich roasting coffee before sorting with a color sorter machine

Onyx Coffee Lab: Using a color sorter machine for coffee to balance quality and volume

Onyx Coffee Lab is a specialty coffee powerhouse. It is one of the world’s most renowned roasters for quality – and has sponsored several US & World Coffee Championship finalists including Morgan Eckroth and Elika Liftee.

This means there can be no compromise on coffee quality – and as a result, it’s crucial to remove every defect that comes through. However, doing this at scale across a high-volume roastery is a challenge.

“While Onyx only sources high-quality coffees with a cup score of 86 or above, there is always a chance of defects being present,” Jet says. “We are also unique in that we have a very large output volume for roasted specialty coffee. In 2024 alone, we roasted around 1.4 million pounds.”

This is why Onyx uses the SOVDA Pearl Mini. When calibrated precisely, the Pearl Mini removes defective beans with a low carryover rate of 10% to 25%. And because it sorts coffee quickly and accurately on its own, it allows roasters time to focus on what matters most – ensuring the roastery thrives.

“We often have a large catalogue of varying origins, varieties, and processes, all with specific roast parameters,” Jet says. “Being able to create and adjust various color and size profiles with the Pearl Mini is crucial for maintaining our quality standards.”

Across the board, SOVDA customers have seen their cup scores improve by two to three points, especially for natural processed coffees. For optimal quality control, Jet recommends that roasters spend time refining their sorting profiles when using color sorter machines for coffee.

“The more effort you put into your profiles early on, the more peace of mind you’ll have long term that your coffee is being properly sorted,” Jet says. “Your customers will definitely appreciate it.”

He concludes by saying that with SOVDA’s support, Onyx is able to provide such consistently high-quality coffee – and ensure they never settle for “just good enough”.

To learn more about SOVDA’s range of products designed to streamline the process of sorting, blending, packing, and storing coffee, get in touch and learn about our products.