Tin ties vs. zippers: Which is best for preserving the freshness of coffee?

Janice Kanniah
July 8, 2022

While coffee may be a shelf-stable product and can be safe to consume after its sell-by date, it will degrade in quality over time. 

For customers to enjoy a coffee’s origins, complex aromas, and flavours, roasters must ensure it is packaged and stored effectively in order to protect these characteristics.

Coffee is known to contain over 1,000 chemical compounds that contribute to its taste and aroma. Processes such as gas diffusion or oxidation during storage can lead coffee to lose some of these compounds. This, in turn, often leads to a decrease in consumer enjoyment.

Notably, investing in the right packaging materials can help protect a coffee’s characteristics. However, the way in which the packaging is made resealable is just as important. 

Tin ties and zippers are two of the most affordable, accessible, and easy-to-use ways roasters can seal coffee bags or pouches. That said, they do not perform the same way when it comes to preserving coffee freshness.

Read on to find out how tin ties and zippers differ and which one roasters should consider when packaging coffee. 

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Close up image of unbleached kraft paper coffee bag with tin tie.

Tin ties and coffee packaging 

Tin ties (also known as twist ties or bag ties) were popularised for widespread use in the 1960s by a farmer who worked in the bread industry.

Charles Elmore Burford was an American who used wire tying technology to seal packaged bread loaves to preserve their freshness.

This was done using a thin length of covered wire. This wire could be fastened around the end of a bread packet and re-tied whenever the bag was opened, and remains popular today. 

Large-scale packagers usually invest in automated vertical Form Fill Seal machines that fill empty bags. These machines also unwind and cut a length of tin tie and then glue it to the top of an open bag. 

The machine then folds each end of the attached tin tie and the bag is taped closed to give it a flat or cathedral top opening. 

Smaller businesses can purchase pre-cut lengths of tin ties or perforated rolls, and glue them to the bags themselves. 

Tin ties can be made from a single material or a combination of plastic, paper, and metal. For many businesses, including coffee roasters, they are a highly affordable solution. 

Notably, many large-scale bread manufacturers are moving away from plastic tags and are once again using tin ties. This is an effective way to appeal to a growing number of eco-conscious customers while also cutting costs.

Additionally, tin ties are more likely to seal a bag without damaging it. For many roasters, using tin ties can help save on costs and they can be attached to coffee bags by hand. Furthermore, they can be removed from packaging and reused.

Depending on the materials used in the manufacturing process, tin ties can be a challenge to recycle. This is because many are made using a galvanised or stainless steel core with a polyethylene, plastic or paper cover.

Finally, tin ties are unable to provide a 100% airtight seal. For goods that are bought and consumed frequently, such as bread, this is sufficient. For a bag of coffee that is expected to remain fresh for several weeks, a tin tie may not be the most effective option.

Close up image of red and white multilayer kraft paper coffee bag with resealable zipper.

Zippers and coffee packaging 

Metal zippers have featured on clothing for decades, but using a sipper to create resealable packaging can be attributed to Steven Ausnit.

Ausnit was the pioneer of Ziploc brand bags, and during the 1950s, he noticed the zippered bags his company produced were confusing for customers. Many simply ripped the zip off the bag instead of opening and resealing it. 

Over the next few decades, he switched to interlocking plastic track and press-to-close zippers. Then, he used Japanese technology to integrate the zipper into bags, making it more affordable for widespread use.

Many businesses still use zipper profiles to create resealable product packaging, and coffee packaging in particular, frequently uses single-track zippers. 

These use a single piece of material to protrude from inside the top of the pouch and fit directly into a track on the opposite side. Some may include dual tracks for added strength. 

Typically, they are added to filled and sealed coffee bags. Users are instructed to cut the top of the bag open and use the zipper below to close it back up. 

Zippers can be 100% water, oxygen, and airtight. However, this level is usually reserved for storing wet products or those that are required to stay dry when immersed in water. 

That said, zippers can still provide a tight seal that keeps out oxygen and moisture, helping to preserve a coffee’s lifespan. 

Important to note is that as many zippers are integrated into coffee bags, they can face similar recycling issues as tin tie bags.

Image of coffee roasters weighing and packaging roasted coffee in kraft paper coffee bags.

Choosing the best option for your coffee packaging

With limited laboratory comparisons between zippers and tin ties to seal coffee packaging, many roasters tend to use a combination of both.

Tin ties are an affordable option that may suit smaller roasters. However, the volume of coffee that is to be packaged will be a deciding factor. 

For those who are using degassing valves and are packaging relatively small volumes immediately after roasting, a tin tie can provide sufficient sealing for a limited time. 

Alternatively, larger volumes of coffee may fare better with a zipper, as it will be opened and closed more frequently. 

Another key point roasters need to consider is that adding a tie or zipper can make coffee packaging more challenging to recycle – regardless of the bag’s materials. 

Therefore, roasters will need to make certain customers can either separate the tin ties and zippers for recycling, or ensure they have a way to recycle the bag as is. 

Some roasters and coffee shops prefer to facilitate this themselves by offering customers a discount in exchange for empty bags. Then, management can ensure the packaging is properly recycled.

Close up image of Caucasian hand holding an open multilayer kraft paper coffee bag filled with roasted coffee.

Choosing how to reseal coffee bags is just one of many decisions roasters will need to make over the course of their packaging journey.

At MTPak Coffee, we can help you decide on the best resealing option for your coffee bags, from pocket and loop zippers, to tear notches and zip locks. 

All our resealable features can be integrated into our recyclable, compostable, and biodegradable coffee bags made from 100% recyclable materials such as kraft paper, rice paper, LDPE, and lined with PLA.

We also offer a perfect solution for micro-roasters by providing low minimum order quantities (MOQ) on both recyclable and traditional options.

For more information on sustainable coffee packaging, contact our team.

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Janice Kanniah
Janice Kanniah

Janice is freelance writer based in South Africa and has written for MTPak Coffee since 2020. Her interests are in writing about sustainability, the circular economy, and the future of the environment.

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