Coffee tastes best when freshly roasted – but how do you ensure your green coffee beans make it to the roaster in optimum condition? It’s all about the storage and packaging used to transport the beans from origin to you, the roaster.
Green coffee is usually stored and transported in one of three main types of bag: jute, GrainPro, or vacuum sealed. Here’s a quick intro into what you need to know about each of them.
Jute / Sisal bags (hessian sacks)
When it comes to packing green coffee beans, hessian sacks made from jute or sisal are the industry standard. Jute is a lengthy, soft vegetable fibre that can be spun into stiff, durable threads. It is one of the most affordable natural fibres and is second only to cotton in terms of numbers produced and variety of use (think Carpets to Car dashboards)
Jute bags are the most cost-effective green bean packing option, which explains why they are so often used. They are also durable and easy to handle, as well as pack and stack.
However, while they may be affordable, jute bags do not protect green coffee from moisture or potential contamination of flavour from strong odours. This can have a negative effect on coffee flavour, which can take on other flavours or be compromised due to mould. Too long stored in the bags, or increased water activity on the bag can also create what is known as a ‘baggy’ flavour to the coffee as well.
Hessian sacks are also unable to control water activity, which is particularly problematic during shipment, when changes in humidity and environment can occur. As a Hygroscopic product, coffee can suffer greatly in fluctuating environments. The moisture content of green coffee should be below 13% percent and is optimal at around 11%. Unstable equilibrium within bean water activity can lead to a loss of moisture and potential oxidisation. Depending on atmosphere, the opposite could also happen, with coffee taking on additional moisture, undesirable flavours and moulding, compromising bean flavour and quality.
Still, jute bags are the industry standard for a reason. They are sturdy, strong and do an effective job of transporting beans when care is taken to protect coffee from contamination.
GrainPro is a welcome improvement and advancement on jute bags, and has risen in popularity in conjunction with the 3rd wave coffee scene. This hermetically (airtight) sealed food-grade zip-locked plastic bag fits inside the regular jute bag and protects green beans by developing a modified atmosphere that stays stable during transport and storage. Whereas a jute bag has a porous open weave which leaves it unable to protect against moisture, the plastic of the GrainPro seals the beans in a stable atmosphere. It also protects against insects and fungal contaminants.
Whilst requesting coffee to be shipped in GrainPro bags bears an additional cost to the importer, GrainPro has become the go-to bag for most specialty coffee roasters due to the benefits the extra expense brings.
One downside to the GrainPro bag however is the handling. Most warehouse operatives use specially adapted hooks to lift the bags, but with protective plastic on the inside, these cannot be used, making handling more difficult.
Vacuum packing green beans is the pinnacle of quality preservation – it is also the most expensive of our three packing types.
Vacuum packing removes all air from the packing bag and preserves coffee flavour for longer, while keeping beans protected from water and other outside influences that affect quality. Vacuum packing machines effectively create a ‘brick’ of solid green coffee beans.
When vacuum packing, it’s vital that beans are well rested and that their water activity has been stabilised. Often packed in boxes smaller than typical sacks (anywhere between 10 – 20 KG compared to jute bags which tend to weigh around 60kg), vacuum packing is great for micro-roasters. As a testament to their quality, all Cup of Excellence coffees are stored in vacuum packed bags.
Longevity of quality
Nevertheless, these stats mean nothing if the handling and transport procedures are not properly adhered to. Temperature and humidity are two factors that should always be taken into consideration to avoid water contamination and maintain the integrity of your coffee. This is not only important for packing, but also during transit and storage. Essential quality control measures include taking regular moisture readings from your green coffee and habitually checking the humidity and temperature of your storage facility.
At DRW, we are careful to ensure our green beans are packed to retain quality when shipped. For our current coffee list, click here.