May 8, 2023

How do specialty roasters manage their green coffee supply?


For any specialty coffee roaster, one of the key factors to running a successful business is a continuous supply of fresh green coffee. Naturally, without this, roasters are unable to sell high-quality roasted coffee.

Sourcing and buying green coffee is certainly a big part of this, but efficient inventory management is also paramount. When stored and used improperly, green coffee will quickly lose its freshness, and thereby its quality as well.

However, with many medium or larger-sized roasters often having anywhere up to a year’s supply of green coffee, how can they manage their inventories as effectively as possible?

To find out, I spoke with Giorgio Mosca, the Export Manager at IMF Roasters. Read on for more of his insight.

You may also like our article on how coffee roasters can design an appealing and efficient roasting space.

Green coffee beans stored in a silo

Why is preserving coffee freshness and quality so important?

Many coffee professionals often talk about coffee freshness in terms of roasted coffee – and rightly so.

The roasting process (essentially applying high temperatures to green coffee) causes a great number of chemical reactions. These reactions then create irreversible changes within the cell structure of the coffee beans – helping to develop flavours and aromas.

Roasting also enables us to grind and brew coffee as the beans become more brittle. However, at the same time, roasting makes coffee a much less stable product. Green coffee can stay fresh for between six months and one year after harvest. Roasted coffee, however, only remains fresh for a matter of weeks.

Once roasted, coffee is more susceptible to a number of environmental factors, such as heat, light, moisture, and oxygen. Ultimately, when exposed to these variables for a significant amount of time, coffee loses its distinctive flavours and aromas more quickly. Eventually, it will taste stale and flat.

Green coffee freshness

However, despite having a longer shelf life, we also need to remember that green coffee can lose its freshness, too. Prolonged exposure to oxygen, water, and extreme temperatures will have adverse effects on green coffee quality and freshness. 

“During roasting, the moisture content of green coffee beans will influence the chemical reactions, and therefore the formation of flavour,” Giorgio tells me.

According to the International Coffee Organisation, the ideal moisture content for green coffee is between 8% and 12.5%. In turn, if the moisture content was to fall outside of this range, roasters wouldn’t be able to get the best out of their coffee.

Moreover, green coffee freshness can depend on a number of other factors. Some of these include:

  • Origin country
  • Harvest date
  • Variety
  • Processing method
  • Bean density

In line with this, roasters need to ensure they store their green coffee in dry, cool conditions to best preserve freshness and quality.

Pile of green coffee beans

Avoiding and mitigating contamination

Not only is preserving green coffee freshness vital for roasters, but maintaining the integrity of green coffee is equally important.

“It’s essential to prevent green coffee from becoming contaminated in the same way as any food product,” Giorgio says. “You need to store green coffee away from excessive humidity and extreme temperatures to avoid the formation of fungi or moulds, as well as to not attract any insects or pests.”

According to European Union regulations, the roasting process is considered a “kill step”. This is a term used in the food safety industry to describe the point where dangerous pathogens and microorganisms are removed from the product. However, it is still possible for green coffee to become contaminated in other ways, which can have a negative impact on quality. What’s more, it could have harmful effects on consumers.

Food safety regulations vary from country to country, so it’s important for roasters to check which ones apply to them. Water activity in green coffee should remain between 0.5% and 0.7% aw (a measurement of vapour pressure between the food product and the vapour pressure of distilled water) in line with food safety protocols.

It should be noted that many food safety laws and requirements fall within the responsibility of green coffee importers and exporters. However, roasters also have a duty to make sure their green coffee is free from contaminants before it arrives at their roastery using a set of quality control checks. Moreover, roasters are also responsible for food safety while the green coffee is in storage, and beyond.

IMF silo in roastery

What equipment do roasters need to preserve green coffee freshness & quality?

First and foremost, upon arriving at the roastery, specialty coffee roasters have to ensure their green coffee is fresh and of a certain quality. Checking for any primary and secondary defects is also important, which can include:

  • Broken beans
  • Black beans
  • Signs of pest infestations
  • Presence of mould
  • Physical contaminants, such as stones or small sticks

“For roasters, it’s crucial that green coffee meets their desired quality standards, especially to maintain consistency throughout the roasting process and in the final product,” Giorgio explains.

Secondly, roasters need to make sure they store their green coffee in optimal environmental conditions. 

For example, to maintain a green coffee moisture level of 8% to 12.5%, a roastery’s storage space should have between 60% and 65% humidity level, with a temperature range of 15°C to 25°C (59°F to 77°F). In order to do this, roasters can invest in a well-designed ventilation system.

In terms of storage equipment, green coffee silos are a popular solution for many roasters. These are specially-designed storage containers which are available in different shapes and sizes. Some silos are polygonal-shaped, while others are circular.

IMF’s silos help to preserve freshness and quality by preventing green coffee from coming into contact with moisture and oxygen,” Giorgio says. “This way, roasters can protect green coffee from excessive humidity to maintain its inherent organoleptic qualities.”

He also adds that alongside storage solutions, IMF also provides equipment for roasters to precisely measure a number of environmental factors, such as humidity and exposure to light.

Roaster holds green coffee

How do specialty roasters manage their stock?

As well as investing in the right equipment, roasters also need to use proper techniques for green coffee inventory management.

Most roasters use a “first in, first out” (FIFO) system for storing and roasting green coffee. This involves roasting coffee in line with when it first arrived at the roastery, while also ensuring all orders stay on track and are fulfilled.

For instance, if a roaster receives a new batch of Colombian coffee from an exporter or importer, they first need to roast any Colombian beans which predate this new batch. As a result, roasters will minimise waste and make sure that the older batch of coffee doesn’t stale and taste flat.

Storing green coffee in silos can assist with the FIFO method, as they are typically designed to dispense coffee beans to be transported to the roaster.

However, prior to roasting, green coffee must be cleaned and sorted. These processes help to remove any defected beans or contaminants.

IMF’s cleaning and sorting machines remove contaminants based on size or weight, such as twigs, stones, dust, and materials from green coffee packaging,” Giorgio explains. “We also provide optical sorting machines which use infrared refraction and multispectral cameras to recognise any foreign objects based on colour and shape which aren’t visible to the naked eye.”

Ultimately, cleaning and sorting systems ensure that green coffee – and thereby roasted coffee – are consistently free from contaminants and impurities.

Two large IMF silos in a roastery

What are the benefits of managing green coffee supplies effectively?

Firstly, it’s important to point out that roasters are obliged to follow food safety regulations, and should therefore always make sure their coffee is free from contaminants and debris.

However, alongside this, many specialty roasters pay high prices for green coffee, so they need to maintain and preserve the quality of their products as much as possible. That way, the end consumer will experience the full range of the coffee’s flavours and aromas – building trust and brand loyalty.

A large part of this lies with consistency. Let’s say a customer orders a bag of Kenyan coffee, and then orders the same coffee again three months later. The customer naturally expects the coffee to taste similar, so proper storage and inventory management is essential to this.

Moreover, if a roaster fails to store green coffee correctly, it can undo the hard work of producers and exporters who have helped to maintain coffee quality throughout the supply chain. Similarly, the coffee will lose its unique characteristics, and may even drop a few points on the Specialty Coffee Association’s 100-point quality scale.

Reducing waste and labour

Finally, proper green coffee inventory management helps roasters to minimise waste, and thereby costs – improving the efficiency of their business.

IMF offers customisable solutions which help roasters manage their green coffee effectively,” Giorgio says. “We design storage and dosing systems which optimise both space and workflow.

“Our automated systems also help to minimise labour, while the centralised filtration system ensures a cleaner and safer workplace,” he adds.

Roaster holds a bucket of green coffee

For any roaster to be successful, proper green coffee inventory management systems are crucial. Without these methods in place, green coffee can quickly become old, stale, or even contaminated.

To ensure that they are always selling high-quality coffee, roasters need to invest in the right storage equipment and implement a set of reliable and consistent stock management techniques. 

Enjoyed this? Then read our article on how heat retention & recirculation can help specialty coffee roasters to improve efficiency.

Photo credits: IMF Roasters

Perfect Daily Grind

Please note: IMF Roasters is a sponsor of Perfect Daily Grind.

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