Cold brew insights from a real coffee sommelier.

While there will always be a place for niche and artisanal cold brew methods in our homes and coffee bars, fast-growing global consumer markets are spurring the development of new recipes and process concepts. Cold brew coffee manufacture is growing up and scaling up. We’re hearing a lot of questions from coffee growers and coffee manufacturers alike. From “what makes a great cold brew?” to “does industrial scale mean lower quality?”

To get expert answers to these questions and a whole lot more, we sat down and chatted with independent beverage developer Esther Merino, who consults internationally on everything cold brew.

What exactly is cold brew coffee?

Starting from basics, cold brew is a solid-liquid extraction in which roast, ground coffee is steeped in low- or ambient-temperature water for prolonged periods. However, Merino suggests, “… we need to understand that cold brew is not simply ‘coffee brewed cold.’ Compared with hot brewing techniques, cold brew is a distinct extraction method that has its own physiochemical logic.”

The smoothness, lower perceived levels of acidity and aromatic balance that we might expect in cold brew result from the combination of many variables, most obviously time, but also bean type and roast, grind size, concentration, water profile and flow. 

Building a scalable extraction process 

From a process perspective, once it’s understood how these different variables interact and how they impact on brew characteristics it becomes possible to think about how to manipulate and structure them as part of cold brew process development.

This is where the relevance of industrial process expertise becomes really evident. GEA is working closely with coffee manufacturers to develop extraction processes that can be controlled to adjust for different interacting variables. Our extraction technologies, including continuous systems designed for low-temperature processing, are engineered to deliver consistent quality while preserving delicate aroma fractions. The goal is to create a reliable, reproducible process that will scale efficiently, and that preserves the sensory profile of the final product. 

Achieving process control and reproducibility at scale can then unlock even greater opportunities for cold brew product development and growth. And that also means putting aside “outdated preconceptions”, Merino notes. “Today, cold brew coffee is so much more than just a ready-to-drink.”  Listening to consumer demand and backed by controlled, scalable processes, manufacturers can think about developing imaginative recipes that create cold brews for different “targeted” applications. 

“There is also great awareness of health and functionality around coffee, beyond its flavor profile. “When we think about coffee components we may immediately focus in on the caffeine, but cold brew also contains terpenes, phenols and antioxidants, which may be functional or support health.” 

Cold brew for health and modern lifestyles

Cold brew coffee is also portable and fits in with our modern lifestyles and “contemporary behavior.”  This then feeds into the modern focus on healthy living and wellness. Coffee is “a commodity that is part of our every day,” Merino notes, so developers and manufacturers can be innovative and inventive, thinking about how to introduce cold brew-based beverages into these targeted markets that support the “everyday”.

And that might include coffee-based cocktails, no-low drinks, fermented beverages, as well as functional and post-functional drinks. We can think beyond cold brew-based options just for that morning caffeine hit or post-exercise energy boost.

And herein producers must really focus on the process itself, and how process parameters influence cold brew characteristics, Merino points out. We can look at adding in fermentation techniques or specialist ingredients to create for each product the ideal sensory experience and flavor profile, while valuing key components and potential functionality. “Ultimately we want to create an organoleptic and sensory experience that the consumer will relate to, and which matches their expectations.”

Moreover, Merino indicates, beyond health and the everyday, different cold brew coffees may be aligned with our “cultural identity”. Not just the cultural identify of consumers themselves, she suggests, but of the coffee farmer, the roaster and even the manufacturer. 

A cultural perspective and identity

We need to build this anthropological understanding into recipes and formats, and quality metrics, she suggests. From cold brew concept to manufacture, considering customer priorities and culture alongside traditional industrial goals - efficiency, reproducibility, sustainability, quality - should be integral to development. And perhaps that will lead naturally to the development of what Merino describes as a specific “sensory vocabulary” for cold brew. “Today our sensory analysis is founded on experiences with hot brew coffee, or from wine or beer. Our vocabularies are based on these well-known categories, but I really think that we need to create a proper vocabulary with descriptors and attributes that specifically fit cold brew.”

This doesn’t mean any less importance should be placed on optimizing key process parameters and linking changes in those parameters to different flavor profiles, she stresses. Coffee quality is, after all, “a cumulative result, and based on choices and decisions – bean origin, roast and grind, process parameters, and particularly extraction time, and downstream handling.” But considering that “anthropological perspective” should become equally important, and mainstream. “And on top of that we also need to be real, because at the end of the day the aim is to create a great tasting coffee that we’ll use every day.” 

More than an increase in capacity

Rather than just increasing throughput, however, achieving desired product characteristics at scale may involve rethinking extraction itself - optimizing flow dynamics, filtration and aroma recovery to ensure that product identity is retained at larger volumes. What works in small vessels may not translate at larger volume. And this can equate to a requirement for reformulation. Flow, filtration, storage conditions may all impact on the final product characteristics and quality.

Merino has previously spent time with GEA, gaining insight into how the company’s engineers and industry experts collaborate with coffee producers to address the challenges of scaling cold brew. This dialogue has underpinned the development and configuration of equipment for key process stages, and in particular aroma extraction. Today the GEA platform spans a range of technology for extraction, from batch-style percolation equipment to fully continuous systems that can be configured to match specific product goals and manufacturing capacity. 

Identifying control points

Merino suggests that taking a structured, stepwise approach to product development from the outset will help to ensure that there is no loss of quality, whether scaling up from a craft, batch process, or establishing an automated industrial process from scratch. “The producer can think about how to consider key variables as ‘control points,’” she states. Developers can establish repeatable experimental processes to manipulate these control points as the foundation for confirming reproducibility, and linking how changing one or more variable impacts on others.

In effect, scaling up needs to start small, and focus on detail. The potential insight that lab-scale tests can give to process and product development is significant, she says, feeding into the scale up workflow, equipment design and configuration, and importantly, creating an environment for ensuring that growth in process capacity will be accompanied by process consistency and reproducibility. 

This transition from laboratory insight to industrial production is increasingly supported by equipment suppliers with deep process knowledge. By partnering with cold brew producers, process equipment manufacturers such as GEA can play an important role in converting laboratory insight into the best systems for processing quality cold brew that retains its identity, at any industrial scale.  

Making the magic happen

Ultimately, of course, producers aim to develop industrial scale processes that retain the key attributes for each cold brew coffee. This will be better enabled through collaboration between all players in cold brew manufacture, from the bean growers and roasters, to process, product and equipment developers, Merino believes.

And that means developing a common language, she suggests, tapping again into the concept of developing a common sensory vocabulary for cold brew that can be linked to process, control, product character and quality “We need to be more rigorous in the language that we are sharing between sensory style, cultural identity, terroir and process.  Every player has their own knowledge and experience, and all of that knowledge is equally valuable.” Combine that collective expertise into a collaborative, relatable learning and support environment, and “that’s when the magic really happens.”