Sterilising cold brew coffee packaging: Which method retains flavour?

Cold brew coffee has been around for generations. However, its growth in popularity has been meteoric – so much so that some businesses may have omitted to appreciate the additional food safety risks

That said, in line with innovation across the coffee industry, the ways in which cold brew coffee is made are evolving. These advancements may have something to do with the health risks that can be involved in the brewing and packaging process. Therefore, one factor brands need to consider is which sterilisation technique is best for its chosen cold brew coffee packaging. 

With all the buzz around cold brew, it’s important to understand how to cater to demand safely. Understanding the risks associated with making and packaging cold brew can help brands mitigate any dangerous bacteria that may result throughout the creation process.

To learn more about sterilising cold brew coffee packaging, I spoke to Mizuki Tsuge, a London-based specialty coffee barista who currently works at Caravan Coffee Roasters.

What are the most common risks associated with cold brew?

Modern cold brew coffee manufacturing includes meticulous sterilisation and packaging processes. These are designed to preserve quality, flavour, and freshness, while ensuring product safety. Brands need to provide a safe, shelf-stable beverage without destroying the complex flavour profile of cold brew coffee. 

Brewing coffee hot naturally eliminates many harmful contaminants through its extraction process. However, the extended brewing time and lower temperatures needed for cold brew can create unique hazards that require careful practices to avoid unwanted microbial growth. The mildly acidic environment is an ideal breeding ground for the growth of multiple different microorganisms, such as bacteria, yeast, and mould. 

If this bacteria multiplies, it can create an environment suited to bacteria known as mycotoxins, toxic compounds produced by fungi that grow on various crops and love coffee beans. From here, the primary concern is the growth of Escherichia coli (E. coli), Enterobacteriaceae (Salmonella), coagulase-positive Staphylococcus aureus (CPS), and Listeria monocytogenes (Listeria), all of which are harmful to human consumption.

If brewing equipment, such as containers and filters, is not thoroughly sanitised, the risk of harmful bacteria growth dramatically increases. 

Understanding sterilisation processes for cold brew coffee packaging

Sterilisation plays a vital role in extending the shelf life of perishable food products, such as cold brew coffee. Beyond this, it helps to ensure the packaging is clean and safe. 

According to US Food and Drug Administration (FDA) regulations, coffee is classified as a ‘low acid food’ with a pH level at or above 4.6. Therefore, it must undergo processing to achieve shelf stability. The processing of cold brew coffee allows it to be stored and transported without the need for refrigeration.

Some of the most common sterilisation processes include heat treatments. That said, each method operates differently, affecting not only microbial safety but also potentially altering the flavour profile of the coffee. However, understanding these processes are essential for making informed decisions about packaging.

The most widely used methods for sterilising cold brew coffee are ultra-high temperature (UHT) and retort processing. Retort is a thermal processing method that eliminates the need for pre-sterilisation of the beverage before packaging. The process begins by filling the chosen packaging with the beverage, which is then sealed. 

Subsequently, the packaged product undergoes heating using steam and/or water at high temperatures for a certain duration. This thermal treatment effectively sterilises the product within the sealed packaging, ensuring its safety and extending its shelf life without compromising quality.

UHT, a pasteurisation process, requires the product to be heated for a brief period to achieve sterilisation. This rapid heating process effectively eliminates microbial activity in the liquid. 

It is important to also note that UHT is the chosen sanitisation option for cold brews that include dairy or dairy-alternatives. This is because it helps to preserve the unique quality of dairy or dairy-like products, such as flavour, texture, and nutritional content. Unlike traditional pasteurisation methods, which may result in some flavour degradation, UHT treatment minimally affects the sensory attributes of dairy. 

Moreover, this method aims to provide the longest shelf life within a refrigerated environment. Notably, brands choosing these options must ensure the cold brew stays refrigerated throughout the entire journey from roaster to consumption. 

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Best sterilisation practice for preserving flavour in cold brew coffee packaging

After undergoing its UHT pasteurisation process, cold brew coffee can then be filtered and packaged into various forms of packaging for convenient storage and safe consumption. The filtration process helps remove any remaining particles or sediment from the cold brew coffee, resulting in a smoother liquid. 

While cold brew is commonly packaged in bottles or cans, flexible spout pouches are also an innovative alternative. Cold brew pouches are designed to be durable, portable, and resealable. Beyond this, the space that one glass bottle takes up during shipping can hold ten coffee pouches, reducing the carbon footprint of the packaging. 

These pouches offer convenience for consumers who may want to enjoy cold brew coffee on the go or in smaller serving sizes. More so, they hold their own when it comes to freshness and shelf life. 

“Being Japanese, I grew up seeing and using cold brew pouches when I was in Japan,” explains Mizuki, who is the quality control assistant at Caravan Coffee Roasters main roastery in the south of the UK. “They are popular not only for coffee but also for making cold brew tea in the summer, as it gets extremely hot in Japan,” she recalls.

“I believe that cold brew pouches help with slowing down the oxidation of the ground coffee by a thin layer of a filter pouch protecting the ground coffee. Oxidation leads to ageing and stale flavours.”

Moreover, while choosing the correct packaging option, roasters must also keep in mind the preservation of product quality and safety throughout storage and distribution.

“Store cold brew pouches in a fridge or a freezer to extend the shelf life and keep the freshness of the coffee,”Mizuki suggests. “These individual pouches are usually sold in a bigger bag, so you could store the whole bag in an airtight ziplock bag.”

“It is a quick and simple way to make tasty cold brew coffee. It’s very easy to clean up as well. Also, I think it allows people to make consistent-quality coffee. You could also play around with making milky cold brew, in which you basically just put a coffee pouch in whatever milk you would like to use. Lightly roasted coffee grounds often work very well,” she adds. 

Ensuring food safety, which encompasses adherence to the FDA’s Food Safety Modernization Act (FSMA) regulations, must be seamlessly incorporated throughout the entire production process. This integration is paramount for sustaining the ongoing prosperity of the cold-brew sector.

For more information on packaging cold brew coffee safely, contact our team. 

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About the author

Holly Szakal is a Melbourne-based copy and content writer and is deeply immersed in her city's vibrant specialty coffee culture. She infuses the rich aromas of the specialty coffee scene by delivering compelling narratives on the industry's current events.