Sea transportation is one of the riskiest moments in coffee’s route from farm to roastery. The beans spend days in a container exposed to high heat and humidity, both of which can cause cup scores to plummet.

To discover how to better protect coffee during sea transit, I spoke to Diego Lara Lavarreda, Global Coffee & Cocoa Specialist at agricultural packaging manufacturer GrainPro, Phitsanuchai “Chai” Kaewphichai, Co-Founder and Business Advisor at Thai coffee producer and distributor Doi Chaang Coffee, and Le Duc Huy, Vice-Chairman at Vietnamese coffee and pepper exporter Simexco Daklak LTD. 

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TranSafeliner installed before the loading process. Credit: GrainPro

The 3 Things That Can Seriously Damage Green Bean Quality

Some say that the moment coffee cherries are picked, the clock begins ticking and the quality starts degrading. 

Many factors affect a coffee’s quality and stability, but once you’re dealing with dried green beans, there are three main issues to consider: temperature, relative humidity, and moisture content. 

Coffee is hygroscopic, meaning it will absorb and retain moisture from the air. Diego tells me of a five-month GrainPro study in Costa Rica in which the moisture content of Arabica coffee stored in an environment with a high relative humidity increased by 2%. 

In extreme cases, coffee’s hygroscopic nature can lead to oxidation and mold. Diego tells me, “Oxidation of coffee beans causes the physical change of whitening.”

Also referred to as being “oxygen-bleached,” whitening happens when green beans absorb significant amounts of moisture from the environment. As the coffee’s physical appearance changes, so does its flavor. A loss of acidity and a baggy or past-crop flavors are the notable effects. 

Meanwhile, mold threatens not just the cup score but the health and safety of consumers. “The biggest problem with highly increased moisture content during transportation is that ochratoxin could be created in the coffee, which is not fit for human consumption,” says Huy.

Diego agrees. He tells me, “Coffee beans affected by oxidation and mold can present a loss of aroma and flavor, resulting in cups that will not meet the quality standards of roasters and consumers. This puts at risk the prices that can be traded between the parties, but also the very health of consumers who are drinking poor-quality coffee with the possible presence of ochratoxins.”

Unfortunately, sea transit can result in those extreme conditions that lead to oxidation and mold.

FIBC Hermetic Pouches are used to store 1–2 MT Big Bags. Credit: Ahualoa Farms

Why Sea Transit Is Particularly Challenging

Imagine a sunny day out near a port, or even on a beach. It is hot, sticky, and humid. Then, as the sun sets, it quickly becomes cool – the type of weather where you might pull on a light sweater.

And now, imagine that green coffee on the ocean freight. It is potentially exposed to this fluctuation of temperature and humidity for days as it makes its way to the destination port.

Add in unpredictable weather patterns, long journeys with possible delays at port, and the differences between the climate of the origin and importing country, and sea transit can pose a significant challenge.

“There are many factors that can affect the quality of the coffee beans during transit, but the most important factors are moisture and temperature fluctuations,” says Diego.

The relative humidity over the ocean depends somewhat on the climate and season. However, according to Senior Research Scientist Isaac Held of the Geophysical Fluid Dynamics Laboratory, part of the National Oceanic and Atmospheric Administration Office of Oceanic and Atmospheric Research in the US, it is “roughly” 80%.

This poses a challenge for the transport of coffee beans. Coffee consultant and author Jean Nicolas Wintgens writes that a relative humidity level of 75% “corresponds to a moisture content in the bean of 15–16%… This is the critical level for fungi formation.”

Fluctuating temperatures increase the risk of mold. Diego says, “The fluctuations between day and night cause… condensation, which will affect the coffee bags and promote the development of mold. Those problems are going to be perceived in the cup and will cause rejections and losses.”

Huy says that this is worsened by the typical supply routes of green coffee. Transporting containers from countries of origin, which typically have tropical climates, to countries that may have cooler, more temperate climates can lead to condensation within the container. 

For some coffee companies, sea transit can cause insurmountable problems. Chai tells me that Doi Chaang Coffee used to ship their beans from Thailand to the United States. Eventually, however, they had to stop selling to this market.

“Some years ago, we had problems with exporting our green beans to North America. We found out that when it reached our customers’ port, the quality had changed due to the long weeks of transit over the sea.”

Not only was his company losing money, but their brand and reputation was being damaged. Even today, no matter the destination, he tells me that “we always worry about how our coffee will reach our customers.”

Process of loading containers in Africa using TranSafeliners. Credit: GrainPro

How to Protect Green Coffee During Sea Transit

Protecting the coffee from moisture and temperature fluctuations is essential, especially during longer journeys. “Select a good transportation service,” Huy stresses.

He recommends looking closely at the ventilation and if containers are dry and in good condition. 

However, it’s not just about the container. Diego emphasizes the importance of hermetic packaging that will prevent gas and moisture from getting to the beans (as well as keeping insects and other contaminants out). 

Chai agrees. He used to use inner linings made of calico cloth. However, he switched to hermetic packaging to better protect the beans. “For many years, we mostly used calico cloth as an inner liner for jute sacks… But we found out that using GrainPro is more suitable and more welcomed by our customers, so we are using it to replace calico cloth sacks. The result is very positive from our customers as we do not have to worry about the coffee quality changing over the long transit,” he says. 

There are two ways to do this: protect the container with a liner and protect the beans themselves with a pouch. Both methods will prevent air and moisture entering, no matter the temperature or relative humidity outside.

In fact, trials conducted by Cafe Britt in Costa Rica and Peru found that adding hermetic cocoons on the storage stage before transportation significantly reduced the sensorial perception of degradation, including in past-crop coffee. The cupping notes from the final blind test said that the sample stored in cocoons had a “very good flavor, despite being from the previous harvest” and “slight floral flavor,” while the control sample had a “slight old flavor perceptible in the cup, slight harshness” and was “tainted.”

TranSafeliner is used in a shipping container. Credit: GrainPro

Sea transit is an almost inevitable part of coffee trading, with many origin countries located thousands of kilometers away from the customer’s port. Yet it comes with risks: falling cup scores, oxygen-bleaching, and even mold. Roasters, traders, and producers need to understand these and appropriately protect their coffee – especially if they’re transporting specialty coffee.

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Written by Sunghee Tark. Featured photo caption: Containers ready to be shipped using TranSafeliners. Featured photo credit: GrainPro 

Please note: This article has been sponsored by GrainPro. Find out here how hermetic technology works for transportation of different agriculture commodities.

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