Sterilisation treatments for cold brew packaging: Which is best?
Cold brew coffee has become a permanent fixture in specialty coffee. By 2025, the value of the global cold brew market is set to increase by over US $1 billion. This represents a staggering compound annual growth rate of 26.44%.
However, the difference in brewing method compared with hot coffee means cold brew poses a higher risk of bacterial growth. To ensure consumers can enjoy the beverage safely, manufacturers must take stringent measures and perform the correct thermal treatments of cold brew packaging and equipment.
To find out more about the importance of safe brewing and which treatments are suitable for cold brew packaging, I spoke to Dr. Dirk Lachenmeier, a food chemist and toxicologist at CVUA Karlsruhe.
The ‘problems’ with the current cold brew industry
Dr. Lachenmeier has much experience in assessing various products within the German market. Part of his role is to ensure the product portrays accurate information on the label that is presented to customers.
He explains, however, that cold brew has no such legal definition yet within the market in the European Union (EU). Essentially, there is no explanation of what exactly constitutes ‘cold brew’, which means there are several products on the market that are brewed in different ways.
“The problem starts with that cold brew is not a designation of the beverage, but more or less a production method,” Dr. Lachenmeier says. “Plus, there are different forms: you can use the ice drip method, or the longer brew at fridge temperature.”
Notably, cold brew coffee is not made using boiling water and allowing it to cool, as the temperatures involved will result in a completely different extraction. “You want to follow a cold extraction method as the coffee will get a different sensorial and flavour profile,” Dr. Lachenmeier explains.
Through his research, Dr. Lachenmeier has found the biggest pitfall with cold brew is that people extract for too long. An over extracted brew will taste bitter. “What we’ve found is that most people put it in the fridge overnight for 8 hours, but that’s too long,” he says. “We’ve done some experiments and found that more or less, the saturation is already reached after some hours. A couple of hours is enough.”
A coffee’s roast profile will affect the solubility of the beans, and in turn, the rate of extraction. Dr. Lachenmeier believes experimentation is the best way to find the ideal roast profile. Lighter roasts prove more difficult to extract, which is why people often shoot for a longer brew time.
Cold brew packaging and product safety
Although they are admittedly rare, food safety issues for cold brew can’t be ignored. And this applies to all manufacturers – ranging from large-scale operations to roasters and coffee shops which serve cold brew.
“You must ensure all equipment is clean to avoid bacteria in the product,” Dr. Lachenmeier explains. “If you let it brew and then stand for too long, it can spoil and begin tasting like fermentation – it tastes like alcohol.
“The best way to avoid this is to ensure brewing and storage vessels are clean and the product is kept in an airtight and sealed container, as oxygen will increase the growth of bacteria.”
It is recommended that cold brew coffee is stored at a refrigerated temperature below 5°C (41°F). While refrigeration will slow microbial growth, it doesn’t completely mitigate it altogether. Studies show that food poisoning bacteria grow best at temperatures between 5°C and 60°C (41°F and 140°F).
Therefore, once brewed and opened, cold brew should be treated like any other beverage (for example milk) and kept below 8°C.
“If you want to see pre-packaged cold brew, you need to do some form of sterilisation to make the product stable and extend the shelf life,” He explains that cans and bottles often undergo a heat sterilisation. “There are chemical preservatives that are used to keep it stable. These are similar preservatives used in other alcohol-free beverages.”
A 2022 study on the effects of sterilsation methods on the flavour of cold brew coffee experimented with pasteurisation, back pressure sterilisation, high temperature short-term sterilisation, membrane filtration treatment, and high pressure processing.
Results showed that non-heat sterilisation can better maintain the sensory quality of coffee liquid. When taking sensory quality, nutrients, and cost into consideration, the study suggested high temperature short time sterilisation as the preferred method.
Investing in cold brew coffee packaging
Several of the risks around cold brew coffee come from brewing equipment, storage temperature, and packaging materials. The coffee beans themselves pose no microbiological risk as they’re sterilised during the roast.
“The main difference would be the sugar content,” says Dr. Lachenmeier. “The more sugar you have, the higher the risk. For instance, a natural arabica would be a risky choice, as it has a higher sugar content.”
Whether a coffee business is just starting to produce cold brew or has decided to scale current operations, food safety for cold brew is paramount. In some cases, this means adopting more formalised brewing processes – which can take some time to implement correctly. A good place to start, however, is simply following standard food safety procedures and checking your local health and safety regulations.
As cold brew coffee is an ever-growing industry, actions must be taken to reduce the emissions and other environmental threats it poses. For example, one step is to invest in sustainable cold brew coffee packaging, such as infinitely recyclable aluminium cans, BPA-free bottles, and flexible pouches made from low-density polyethylene (LDPE), or polylactic acid (PLA).
At Cold Brew Pak, we offer sustainable cold brew packaging that is both affordable and fully customisable. We can create bespoke cold brew coffee packaging for your unique collaborations while ensuring the carbon footprint of your business remains low. We offer a range of sustainable cold brew packaging structures, such as flexible spouted pouches, bag-in-box solutions, cans, and BPA-free bottles.
Talk to our team to find out more.
