What’s the difference between bleached & unbleached kraft paper coffee bags?

Jane Merchant
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February 23, 2022
Caucasian woman pouring roasted coffee beans from unbleached kraft paper coffee bag into a coffee grinder

As more countries implement plastic bans, the global paper packaging market is larger than ever.

It is estimated the demand for paper bags and sacks will reach $323 billion USD by 2026. This demand is predominantly driven by consumer concern about how plastic packaging affects the environment.

Paper is one of the world’s oldest and most popular packaging materials for roasters. Typically, they choose kraft paper to package their roast coffee as it is affordable, strong, and recyclable.

However, roasters will need to decide between bleached and unbleached kraft paper. Each has its benefits and can highlight different aspects of your business, such as sustainability or branding.

Here’s how bleached and unbleached kraft paper compare, and how roasters can choose the best option for their business.

Close up image of unbleached kraft paper, brown in colour, with small rip along left hand side

What is kraft paper?

While people have used paper to package food for centuries, the idea only took off in the 1800s thanks to the invention of paper-making machines. 

These machines used steam power to produce packaging from wood pulp, making paper packaging a cost effective option for many businesses. 

Then, in 1879, Carl F. Dahl, a German chemist, developed the kraft process that produces the brown paper many roasters use today. 

By boiling wood chips in sodium hydroxide and sodium sulphide, Dahl discovered he could convert wood pulp into strengthened cellulose fibres. 

Essentially, he broke the bonds linking the pulp’s lignin and cellulose. Lignin is the chemical compound in wood that makes it strong. 

However, it is hydrophobic, which means it keeps hydrogen bonds from forming between the pulp’s cellulose fibres. By removing these links, Dahl created a stronger paper

While Dahl is credited with inventing kraft paper, George H. Tomlinson made the process sustainable. In the early 1900s, Tomlinson developed a machine which acted as a chemical recovery furnace. 

He harnessed the energy generated by the paper milling process to power the mill, making the paper production process self-sufficient.

Caucasian hand holding up unbleached kraft paper coffee pouch with white specialty coffees label stapled to top, on white background

Kraft paper coffee bags: Bleached vs unbleached

In its unprocessed state, kraft paper is brown or yellow, while bleaching can make it whiter and brighter. 

The bleaching process removes lignin, which gives the paper its hue. 

During the early stages of the kraft process, most lignin is removed. However, some remains in the paper and it takes several stages to bleach it to the desired level of whiteness. 

Traditionally, chemicals such as chlorine gas or hydrogen peroxide are used to oxidise the pulp. Then, sodium hydrosulfite removes its hydrogen to extract more lignin, and the paper is immersed in an alkali solution to remove it.

Unbleached paper usually goes through a five step process of chlorination, two alkali extractions, and two chlorine dioxide treatments.

In between each bleaching step, the paper is washed to remove excess lignin and other chemicals. It’s also heated to shorten the bleaching process and ensure uniform chemical distribution. 

At the end of the bleaching process, the remaining pulp mixture is then sprayed out and dried before being flattened and stretched. Finally, heat rollers press it into sheets and it is trimmed into rolls.

Roasted coffee beans tumbling out of a white, bleached kraft paper coffee pouch lying on its side on white table with sandstone colour background

Which is better?

The main difference between bleached and unbleached kraft paper is appearance. 

Unbleached kraft has a rustic look and feel that appeals to roasters who want their products to look environmentally friendly.

Additionally, it is more likely to satisfy customer concerns about sustainability and may encourage them to recycle the packaging.

Furthermore, unbleached kraft paper is ideal for packaging coffee as it is strong and lightweight, so it will not add to your packaged weight and size. 

On the other hand, bleached kraft paper lends itself well to brands who want to highlight their commitment to environmental sustainability.

Not only can it be dyed and printed with any colours and images imaginable, but the stark white colour ensures your branding will stand out. 

A common misconception is that the bleaching process makes this kraft paper less sustainable.

Modern paper manufacturers have switched to using oxygen, ozone, or hydrogen peroxide to bleach the paper. This produces fewer toxic and carcinogenic compounds that could damage the environment.

Close up of the top of an unbleached kraft paper coffee pouch, closed, highlighting the resealable zipper.

Other factors to consider

While both variations of kraft paper are recyclable, biodegradable, and compostable, they have certain qualities roasters should consider before committing to either one. 

In their natural state, bleached and unbleached kraft paper has poor barrier qualities, making it vulnerable to moisture, heat, and light. 

Therefore, when packaging larger quantities, the kraft paper will need to be lined with a stronger barrier material to preserve the coffee’s quality. 

A degradable lining such as polylactic acid (PLA) has a high tensile strength and can withstand temperatures of up to 215°C (420°F). Additionally, it has good water vapour and humidity barrier properties. 

PLA also breaks down in as little as 90 days when placed in a commercial composting environment. 

Another key point is to ensure the paper packaging you choose is sustainably sourced. 

Ideally, the paper must be certified by the Forest Stewardship Council (FSC). This signifies it is from a responsibly managed forest that matches a strict third-party criteria.

Furthermore, adding the FSC logo onto your packaging can give customers a visual ensuring the packaging has been sustainably produced. 

unbleached kraft paper coffee pouch lying flat on countertop along with a metal bowl filled with roasted coffee beans.

When choosing kraft paper packaging for your business, it is vital to balance its sustainable qualities with its ability to protect and preserve your roasted coffee. 

Working with a coffee packaging specialist can simplify the process and give you peace of mind that your packaging is a true representation of your business. 

At MTPak Coffee, we can provide you with FSC-certified branded unbleached or bleached kraft paper packaging, complete with eco-friendly liners for added barrier protection.

In addition to UV printing methods, we use sustainable, water–based inks to ensure your branding stands out to consumers while limiting environmental impact. These are low in volatile organic compounds (VOCs).

We also offer recyclable BPA-free degassing values and resealable zippers to help preserve the freshness of your roasted coffee, from the roastery to the consumer.

For more information on our kraft paper coffee bag options, contact the team today

What’s the difference between bleached & unbleached kraft paper coffee bags?

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