Over the last decade or so, cold brew has transformed from a niche offering to a menu staple. According to the National Coffee Association’s most recent 2025 National Coffee Data Trends report, past-day consumption of specialty non-espresso-based beverages (which include cold brew) shot up by nearly 42% between 2020 and 2025.

As consumer demand continues to grow, coffee shops and roasters must consider an often overlooked aspect of cold brew production: food safety. In recent years, several studies have highlighted cold brew’s susceptibility to the growth of harmful bacteria and pathogens, primarily due to its low brewing temperatures and low acidity levels.

To understand how roasters and coffee shops can prioritise cold brew food safety, I spoke with Antonia Bordeianu, Q grader and lab coordinator at Origo Coffee, and Krzysztof Barabosz, head of coffee at Hardtank.

You may also like our article on why the coffee industry needs to take cold brew food safety seriously.

The importance of cold brew food safety

The rapid expansion of the cold brew coffee market has prompted an increasing number of roasters to develop their own cold brew products, capitalising on the boom in consumer interest. Although lucrative, this surge is simultaneously highlighting significant, previously overlooked food safety concerns.

Unlike hot coffee beverages, cold brew’s low brewing and serving temperatures create ideal conditions for microbial growth. Combined with lower acidity levels, this results in an environment where microbes can thrive if proper precautions aren’t in place.

Research from the University of Georgia shows that four different common strains of bacteria can survive up to 12 days in cold brew, effectively meaning that if contamination occurs when preparing cold brew, the risk of certain bacteria growing and surviving increases, and could potentially infect consumers. 

Cold brew’s longer shelf life also presents unique challenges. While people consume hot coffee beverages immediately after preparation, cold brew is often stored and used over longer durations. Without proper handling procedures, this results in additional contamination and microbial growth opportunities.

“We conducted a study with the Institute of Microbiology at the University of Opole, where we examined the microbiological risks in immersive, 24-hour cold brew coffee stored in different conditions,” says Krzysztof Barabosz, head of coffee at Hardtank, a commercial cold brew equipment manufacturer and private label RTD coffee supplier. “The research focused on the impact of cleaning methods, storage temperatures, and storage time on bacterial and fungal contamination levels.

“We saw a massive yeast growth, including Rhodotorula and Candida intermedia, when stored at 25°C, already after 24 hours. This is quite interesting because coffee doesn’t contain yeast,” he adds. “When we assessed the growth, we found the yeasts had come from the palms of the hands of the people who handled the coffee.

“Rhodotorula is an environmental yeast that can be present on human skin, supporting the premise that human hands can serve as a direct source for their transfer to food products. Yeast can originate from the palms of the hands of people roasting and packing coffee beans, especially when they don’t use personal protective equipment,” he continues.

“Human skin naturally harbours various yeast species, including Candida and Rhodotorula, which were identified as significant contaminants. Scientific literature consistently confirms that inadequate hand hygiene is a primary vector for microbial cross-contamination in food processing, with direct evidence of human-associated fungi being isolated from commercial coffee products. We also observed E. coli within 24 hours when the cold brew was stored in an unsterile keg.”

What are the contamination risks when making cold brew?

Without proper preparation methods and pasteurisation, cold brew coffee can easily become contaminated at various stages of production. Many roasters and café owners may not fully appreciate these risks, having traditionally prepared cold brew in-house using more basic equipment and techniques.

“Oxidation, unclean equipment, open tanks, long extraction times, lack of control over the brewing and storage over extended periods, issues with general hygiene – everything contributes to triggering a deterioration of cold brew, leading to spoilage,” Krzysztof says. 

Hardtank recently hosted a webinar, How to Prepare Cold Brew Safely: Minimising Microbial Activity, which focused on the biggest risks in cold brew preparation and how to avoid them, as well as industry best practices to ensure food safety compliance and how to control microbial activity to keep cold brew fresh and safe.

Some common sources of contamination include:

• Equipment contamination: Brewing vessels, filters, and dispensing systems can harbour bacteria if not thoroughly cleaned and sanitised between batches.
• Water quality issues: Substandard water can introduce various contaminants into your cold brew.
• Cross-contamination: Improper handling practices can transfer pathogens from other food preparation areas.
• Inadequate cooling: Failure to rapidly cool and refrigerate cold brew after filtration can create conditions for bacteria to multiply.
• Insufficient sanitisation: Many small-scale operations lack formal sanitisation protocols for their cold brew equipment.

“There are no shortcuts to great coffee, nor great cold brew. Low acidity and cold extraction make it a sensitive format, both in taste and in safety,” says Antonia Bordeianu, a Q grader and lab coordinator at Origo Coffee, a specialty coffee roaster in Bucharest, Romania. “We use tightly controlled parameters and a calibrated process every step of the way: we monitor TDS and pH for each batch, and we track every variable, from green coffee and water quality to bottling.”

Every step in the cold brew preparation process has an impact on not just how the coffee will taste but also on how safe it is to consume. Cold brew, especially when unpasteurised, must be stored below 5°C. 

Specific storage conditions are necessary to keep cold brew within the optimal temperature range in clean, sterilised equipment. Without this, cold brew spoilage can lead to significant wastage for roasteries and coffee shops, resulting in unnecessary costs.

The importance of specialised cold brew equipment

The best way to avoid wastage and maintain the highest food safety standards would be to make cold brew fresh on demand. Given the longer preparation time compared to hot coffee beverages, however, this proves impractical for coffee businesses.

As the cold brew category matures and new brewing technology emerges, roasters and coffee shops are transitioning from improvised production methods to professional-grade equipment. This shift allows them to adhere to both food safety standards and their own high standards for quality and consistency.

“Cold brew shifts the margin for error. At a certain level of consistency and scale, equipment isn’t just helpful, it’s necessary,” says Antonia. “Roasters and coffee brands who want to deliver cold brew with stable quality over time need systems that offer both repeatability and control.

“For us, that meant choosing Hardtank, not to replace craft, but to support it with more control. It allows us to translate intention into method, being able to replicate the same clean, sweet, complex profile that we aim for, with precision that holds across every cold brew batch.”

Cold brew production volumes will inevitably vary from roaster to roaster. For businesses that sell larger quantities or offer ready-to-drink cold brew – whether through wholesale or D2C channels – the need for professional-grade equipment naturally increases.

The Hardtank H20, for example, offers a complete solution for brewing and serving cold brew. It can brew and dispense up to 250 liters (or 1,250 portions) of cold brew coffee per day. The extraction takes place in a sealed, pressurised environment, which minimises oxygen exposure and helps protect the coffee’s more nuanced attributes, like flavour clarity and sweetness.

“We use the H20 as part of a calibrated system, not just to brew, but to control. For example, when developing cold brew from a naturally processed Brazilian coffee with a chocolatey, smooth profile, we calibrated a 140-minute extraction to enhance sweetness and body,” Antonia says. “Meanwhile, for washed Ethiopian coffees, we extract for 90 minutes to preserve floral and citrus notes. 

“In the case of our winter blend, we fine-tune the agitation and timing to retain delicate notes of orange and vanilla.”

Food safety at the forefront

The cold brew revolution presents tremendous opportunities for coffee businesses, but capitalising on these opportunities requires a commitment to food safety that matches the industry’s dedication to quality and flavour. 

By making food safety a non-negotiable in cold brew production, roasters protect both their customers and their business for the long term. So, in addition to supporting roasters and coffee shops in preparing and serving high-quality cold brew, the equipment needs to streamline food safety processes.

The Hardtank H20’s built-in tap, for instance, allows for easy, sanitary filling without introducing additional contamination points. More importantly, the system features self-cleaning and sanitation programmes that can be scheduled to run automatically, ensuring consistent adherence to hygiene protocols, even during the busiest times of the shift. 

“At Origo, we integrate these functions into our daily production flow. Every cycle is logged, verified, and followed by lab testing of the final product,” Antonia says. “The H20 doesn’t just support compliance with food safety standards, it makes sanitation an active, trackable part of our brewing protocol. That consistency allows us to work without preservatives and still deliver a clean, shelf-stable cold brew.”

The machine’s automatic drainage system eliminates standing water that could harbour microbes between brewing cycles. This feature, combined with precise temperature control throughout the brewing process, addresses two of the most common vectors for contamination in cold brew production.

As the cold brew category continues to mature, we can expect increased regulatory scrutiny and more stringent safety standards. Forward-thinking businesses are getting ahead of this curve by implementing comprehensive safety programmes now, rather than scrambling to comply with future regulations.

Success comes from treating cold brew as a format with its own rules. This means investing in proper equipment, designing repeatable workflows, and knowing exactly what kind of cup profile you want to achieve.

Enjoyed this? Then read our article on why roasters need to stand out in the RTD cold coffee market.

Photo credits: Nadya Glovatcaia

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