What if your daily chocolate or coffee could be brewed without farms—or deforestation—but straight from a bioreactor? It sounds like a technological fantasy, but plant cell culture is quietly remaking some of the world’s most beloved food staples. This episode cracks open the world of cellular agriculture, moving beyond the hype of lab-grown meat to explore how plant cells are ushering in a new era of sustainable food manufacturing.

Joining Smart Biotech Scientist Podcast host David Brühlmann is Steven Lang, Head of R&D at California Cultured. Steven is no stranger to ambitious challenges. After nearly two decades in biopharma with industry giants like J&J and Genentech, he pivoted toward cultivated foods, determined to go beyond the narrow focus of animal cell-derived products.

Key Topics Discussed

• Reimagining food production by making chocolate and coffee without traditional farming through cellular agriculture.
• California Cultured’s progress using plant cell culture and bioreactors to produce cocoa and coffee.
• Environmental, flavor, and sustainability advantages of cultivated plant cells over conventional agriculture.
• Steven Lang’s journey from biopharma to food biotech, driven by health, sustainability, and food security.
• Defining cellular agriculture and clarifying distinctions between cultivated meat, plant cell culture, and precision fermentation.
• End-to-end cocoa and coffee production via plant cell culture, from explant to scalable bioreactor production.
• Product quality, non-GMO positioning, sensory consistency, and consumer acceptance challenges and solutions.
• Commercialization strategy, bioreactor innovation, and the path from premium products to global scale impact.

Episode Highlights

• The evolving definition of cellular agriculture—its scope beyond cultivated meat [07:16]
• Technical insights into growing cacao cells in bioreactors, comparing plant and animal cell culture [09:26]
• How California Cultured minimizes downstream processing and achieves product consistency [11:14]
• Discussion about media costs and how plant cell culture differs from animal cell processes [14:38]
• The financial and strategic advantages of starting with premium products like high flavanol cocoa powder [15:58]
• Bioreactor choices, contamination control, and how process design is adapted for commodities and scalability [18:23
• Onshoring and decentralizing production for greater global accessibility, including applications in emerging markets [23:10]
• The broader impact and future possibilities of plant cell culture in biotech and food industries [24:23]

In Their Words

Cellular agriculture is using cell culture to produce agricultural products. And the frustration that I've had over the last three or four years is that everything that is considered cellular agriculture is actually synonymous with cultivated meat. And there's so much more to cellular agriculture than just meat.

I really want, through this venue as well as other venues, to drive home the message that cellular agriculture includes any type of cell culture product that can be derived from animal cells like cultivated meat, plant cells like cacao, or precision fermentation with microbial cells. And that broader definition of cellular agriculture is important to me because I see there is a resistance from consumers to adopt or try cultivated meat.

From Cultivated Meat to Chocolate: Rethinking Cellular Agriculture Scale-Up - Part 1

David Brühlmann [00:00:55]:
Imagine a world where your favorite chocolate bar doesn't require a single cacao tree, where coffee comes from a bioreactor, not a plantation. Sounds like science fiction. It's happening right now in California. Today we're joined by Steven Lang, who is the head of R&D at California Cultured, who left two decades in biopharma to revolutionize how we produce food. He's cultivating plant cells to create real cacao and coffee. No farms, no deforestation, no compromise on flavor. Let's explore the future of what we eat.

Welcome back, Steven, to the Smart Biotech Scientist. It's a pleasure to have you on today.

Steven Lang [00:02:52]:
It's great to see you again, David. I'm really pleased to have this conversation again and catch up.

David Brühlmann [00:02:57]:
Sure, Steven. Share something that you believe about bioprocess development that most people disagree with.

Steven Lang [00:03:06]:
Interesting. Well, since we talked last, the thing that I've really come to learn is that we need to walk before we can run. And that is not necessarily around bioprocess development per se, but it's more on the biotech industry and how we have to have stage-appropriate models to really kind of push this industry forward. We can get into more of those details, but that's kind of a nutshell of what I think—that we need to really look at simpler models that can help us answer some of these fundamental questions, not only on the technical side, but also on the consumer acceptance side.

David Brühlmann [00:03:39]:
I like that. Learn to walk before you run.

Steven Lang [00:03:43]:
Exactly. Yeah.

David Brühlmann [00:03:45]:
And I'm excited to have this conversation today on cellular agriculture. Let's start with you, because not everyone listened to our first conversation. So I'd love to hear your origin story—what sparked your interest in biotech and what were some pivotal moments, because a lot of things happened actually since we last spoke.

Steven Lang [00:04:05]:
So my origin story we kind of went into in the last podcast, so I'd recommend listeners go back and listen to that one. But just as a synopsis, I've got almost 20 years of experience in biopharmaceuticals with large, mature pharmaceutical companies—Johnson & Johnson and Genentech—as well as small CROs.

About four years ago, I decided that I wanted to do something a little bit different outside of the pharmaceutical arena. The opportunity came along to work on cultivated meat, which blew my mind, because using these expensive bioprocessing technologies to produce a commodity just doesn't make any sense.

As we spoke about back in 2023, that's really exciting for intelligent people—to have huge, audacious challenges to take on—and certainly cultivated meat presented that to me. That's what got me interested in it.

Throughout the biotech industry, there's been a lot of retraction and consolidation, especially in the food sector, which is more cost-conscious than the pharmaceutical sector. I was caught up in that and was laid off from UPSIDE Foods as part of a reduction in force, as they were consolidating their resources to extend their runway. I thought that was a little bit shortsighted, but I wasn't making those decisions.

I took about eight months off and did some introspection on what I wanted to do with the rest of my career. That brought me to wanting to have a larger impact on the world beyond just human health. That's where the opportunity came along to join California Cultured.

As we talk further, I hope to elaborate on how this cell culture technology can really have an impact on human health, food security, and sustainability—all of which are near and dear to my heart. Having the opportunity to work on something with that type of global impact was really compelling for me.

So I made the jump without much hesitation into California Cultured, where we're producing cultured chocolate (cacao powder) to begin with, as well as coffee. Those are the first products we're planning to get out the door.

This is a relatively small startup—about 18–19 people—founded in 2020, and we're building out not only plant cell culture products, but also the supporting biomanufacturing processes. We're actually developing new bioreactors for plant cells, which is fascinating work as well.

David Brühlmann[00:06:37]:
Yeah, I'd love to dive into more. It's fascinating, and I must say I'm a bit biased. As a Swiss, I love, love, love chocolate. And I ask some critical questions.

Steven Lang [00:06:49]:
Perfect, I'm ready for them.

David Brühlmann [00:06:57]:
Let's unpack it from the start because we have heard, or some of you listening have heard, the term cellular agriculture. But even to me, sometimes it's not clear what exactly is in that field. It's also evolving. So I would love to hear your definition. What is inside? Is even cultivated meat inside of that, or is it outside? Tell us more.

Steven Lang [00:07:16]:
No, that's great. Really good question. Because I think this definition has been evolving, and it's important for us as an industry to consolidate around a single definition. And I think that definition should be that cellular agriculture is using cell culture to produce agricultural products.

The frustration that I've had over the last three or four years is that everything that is considered cellular agriculture is actually synonymous with cultivated meat. And there's so much more to cellular agriculture than just meat. I'd also like to argue that the focus on cultivated meat has done us a disservice, because we have had some opposition to cultivated meat—political arenas, political grandstanding—where states and even countries have banned lab-grown meat even before it's available on the market.

So I really want, through this venue as well as other venues, to drive home the message that cellular agriculture includes any type of cell culture–derived products from animal cells like cultivated meat, plant cells like cacao, or precision fermentation with microbial cells. And that broader definition of cellular agriculture is important to me because I see resistance from consumers to adopt or try cultivated meat. So we need to get away from the singular focus on cultivated meat and move more toward these other products that people understand better and adopt more easily.

David Brühlmann [00:08:50]:
When you say precision fermentation is part of cellular agriculture, what comes to my mind—and this is a question—is beer production part of cellular agriculture or not?

Steven Lang [00:09:01]:
You could argue that, but it's traditionally been called fermentation, which is a stretch. You could call that precision fermentation.

David Brühlmann [00:09:08]:
Okay, fair enough.

Steven Lang [00:09:10]:
I think of precision fermentation as really using genetically modified microbes to produce a specific product, whereas beer and wine fermentation are essentially producing alcohol—which is important—but it's not as complicated as, say, producing lactoferrin from yeast.

David Brühlmann [00:09:26]:
Let's walk through the fundamentals of what you're doing. You're now growing cacao cells in a bioreactor. Tell us more. How does this work? Is it similar to a CHO cell culture? Is it very different, and more?

Steven Lang [00:09:40]:
I like to say cell culture is cell culture. What we do in plant cell culture is very analogous to a CHO cell line in cell line development or any type of cultivated meat, where you take a biopsy from the agricultural plant or animal, and you immortalize those cells and then expand them to produce biomass that is the product. So there are no differences there.

The differences are really about the terminology. With plants, what we do is take an explant instead of a biopsy. And plants are interesting because all of their cells are totipotent, so they can be differentiated into a full plant from any individual cell.

What we've done here at California Cultured, with our cell line development group, is take explants from a cacao pod. We aseptically open the pod, expose the beans inside, and take explants from those beans. Those explants are then put on solid agar media and induced to dedifferentiate. Those are called callus cells.

This technology has actually been around longer than a lot of animal cell culture, because it was historically used to propagate plants for the field. We can take those callus cells on the plate and use them as a cell bank, then screen and select the cell lines we want and adapt them to suspension culture, much like you would with animal cells, and then scale them up.

From there, once we go into scaled production, it's a very simple process—very much like cell culture. We're controlling the environment and the culture, running for a certain number of days, and then harvesting the bioreactor.

One big difference with the plant cell culture products we're working on is that there's relatively little downstream processing. Our downstream processing is dewatering, drying, milling, and packaging. Compare that to cultivated meat, where you take the biomass from the bioreactor and then have extensive downstream processing—such as scaffolding, maturation, or formulation with animal or plant-based proteins to create a meat analog.

With our plant cell culture products, downstream processing is very simple. And I think that alleviates some consumer concerns about cellular agriculture products because it's easier to understand. The products coming out of the bioreactor also really look like conventional cocoa powder or coffee. So it's easier for consumers to connect what we're producing with what they already think of as cocoa powder and coffee.

David Brühlmann [00:12:33]:
Regarding consumer acceptance, I think this cocoa product is much easier to sell because it's not a genetically modified cell, correct?

Steven Lang [00:12:43]:
Correct. We have not done any genetic modification to our cell lines or products. We're relying on the natural diversity in the genetics and epigenetics of cacao to select the cell lines we're interested in—not only based on growth parameters, but also the phenotypes we care most about, which are the sensory attributes and higher levels of bioactives that are important in cacao and cocoa powder.

David Brühlmann [00:13:11]:
Do you clone the cell or your cell lines as you would do in cell culture?

Steven Lang [00:13:16]:
Not necessarily. Since we're not doing any genetic modification, we don't need to ensure that our product originates from a single cell, like what the FDA requires for biopharmaceuticals. Essentially, we do perform clonal selection, but these cells tend to aggregate, so it's difficult to say whether the production unit is a single cell or an aggregate.

That said, we have strict quality control processes and specifications to ensure we're producing a safe, high-quality product.

David Brühlmann [00:13:46]:
And how do you manage the variability that comes from different cells? I imagine the taste will change, maybe the texture.

Steven Lang [00:13:55]:
There's not a lot of that. Right now, what we're finding is that if you control the environment very carefully for plant cells, you can control the consistency and quality of the product coming out. So we’ve been sticking with a very straightforward media and process, and we’ll talk more about that. The bioreactors themselves are pretty consistent, and that gives us stable production over time.

What we’ve demonstrated so far is stability over about six months at the lab scale. When we move to full scale, we’re hoping to translate that stability into a continuous manufacturing process.

David Brühlmann [00:14:30]:
I'm curious about the media cost, because that's a big challenge in the cultivated meat space. How does that work in cacao?

Steven Lang [00:14:38]:
Plants in the field just need fertilizer. And since we're growing them without sunlight, they also need a carbon source. Our media is relatively simple—about 18 components, compared to animal cell culture media, which typically has 40 to 60 components, including some very expensive growth factors.

Our components are mostly fertilizers—phosphorus, nitrogen—plus a carbon source and some relatively inexpensive growth factors that are already found in conventional food we eat today.

David Brühlmann [00:15:13]:
All of the components you're using are chemically defined, correct?

Steven Lang [00:15:16]:
Correct—chemically defined media. I should also add that all the components we’re using have gone through a GRAS (Generally Recognized As Safe) process and are totally acceptable for food production.

In addition to having fewer raw materials, the costs are dramatically different. Back when I was doing cell line development at Johnson & Johnson, we were paying around $40 per liter for media. I don’t know how much that’s changed, but in plant cell culture, we’re well below $10 per liter, and we expect to get below $1 per liter.

David Brühlmann [00:15:48]:
Wow. And what about the economics? Is it relatively easy to reach a point where the product is profitable?

Steven Lang [00:15:58]:
Yes, absolutely. And I should back up and describe our first product coming out the door, which is a high-flavanol cocoa powder. We’ve selected a cell line that produces higher levels of flavanols, which are bioactive compounds responsible for many of the health benefits of dark chocolate.

There was a very large clinical study called the COSMOS Trial, which included more than 21,000 participants, mostly elderly, and more than half had pre-existing conditions such as cardiovascular disease or diabetes. This long-term study supplemented diets with 500 mg of flavanols per day and found a 27% reduction in cardiovascular events. Additional analyses are still coming out of that study.

So we’re interested in improving not only flavor and taste, but also the health benefits of cocoa powder. Through our cell line selection, we believe we can do that. This allows us to enter the market with a premium product at a higher price point.

While we scale that product and generate revenue, we’ll continuously work on improving COGS and processes to reduce cost. That will allow us to move into commodity cocoa and eventually other products like coffee. So we start premium and then move toward commodity products.

David Brühlmann [00:17:38]:
That's an excellent strategy.

Steven Lang [00:17:40]:
Yeah. Other companies are doing this as well. I like to point out Gourmey, which has been very successful in France producing cultivated foie gras as a premium product. It really is the way to go—it’s more of the Tesla model, where you launch with a premium product first.

David Brühlmann [00:17:57]:
Yes, exactly. It’s a Tesla model.

Steven Lang [00:17:59]:
Exactly.

David Brühlmann [00:18:00]:
Before we go on to flavor, I just want to dive into the bioreactor side for a minute, because not everyone listening is familiar with plant cell culture. Can you describe how the bioreactor looks? What parameters are you controlling? How does a run typically work? Is it batch, fed-batch, or—you mentioned continuous—how does it work?

Steven Lang [00:18:23]:
With these cacao cell lines and our cocoa powder product, we’ve run the cells in both stirred-tank bioreactors and airlift bioreactors. They’re very robust and grow under a wide range of conditions, so we don’t have to control very much.

In one of your previous podcasts, you talked about Process Analytical Technology (PAT). For us, the main parameter we control is dissolved oxygen. These plant cells grow at ambient temperature, relatively low pH, and all they really need is oxygen and nutrients.

That’s not to say the processes are trivial, but they’re very flexible, and we can use different reactor modalities. Right now, we’re running batch processes, not fed-batch. A typical run starts with inoculation, and about seven days later, we harvest.

We use a higher inoculum than typical animal cell culture, but our cells are also much larger. We usually start with about 5–10% packed cell volume (PCV), and by harvest we reach 30–40% PCV. That yield is dramatically higher than what you typically see in even highly optimized animal cell culture processes.

So right out of the gate, the amount of biomass we can generate from plant cell culture is significantly higher than what animal cells can produce.

David Brühlmann [00:19:50]:
And how long does a run typically last?

Steven Lang [00:19:52]:
For seven days. And the seed train running up to that is your typical four- to five-day split ratio. Depending on the scale you're going up to, you'll need that time to get the inoculum ready for the final production vessel.

David Brühlmann [00:20:07]:
And what vessels are you using in the seed train? Are these shake flasks, spin tubes, the usual sub-specs, all that?

Steven Lang [00:20:14]:
Standard stuff—shakers and shake flasks, Fernbach flasks, the larger shakers—until we get into the bioreactors. At very small scale, starting at 5 and 10 liters, we keep them in a controlled environment, then scale from 5 to 10 liters to 100 liters, 500 liters, and then 2,000 liters.

David Brühlmann [00:20:34]:
How critical are these cultures with respect to contamination?

Steven Lang [00:20:39]:
The major problem with any scaled cell culture is contamination—how do you maintain a sterile envelope for the cells to really take off? The nice thing about plant cells, as I mentioned earlier, is that the culture media has a relatively low pH, which is not conducive to microbial growth. In addition, plant cells themselves produce antimicrobial compounds that help fend off contamination.

That said, we still deal with contamination, and that’s something we’re actively working through. As we talk about some of the bioreactor innovations we’re developing to create low-CAPEX, low-OPEX bioreactors, the sterilization strategy is a big part of that.

David Brühlmann [00:21:24]:
And you're using stainless steel tanks for the cell culture—it's not single-use, right?

Steven Lang [00:21:29]:
We’re not single-use, and we’re also not stainless steel, because we’re going after commodity products. One of the things that really attracted me to this company is that they’d clearly thought through the business model and understood they’re targeting commodities, so everything has to be interrogated for cost reduction.

Right now, we’re working with plastic bioreactors. The reason is simple: we can buy a 2,000-liter plastic tank for about USD 3,000. Try buying a 2,000-liter stainless steel bioreactor for less than USD 1 million. Right there, you can see we’re taking a very different approach—maybe even recreating the wheel in some cases.

But our cells are well suited to these low-cost bioreactors, which we can then scale out very easily. Another important part of the business model is that instead of scaling up beyond 2,000 liters, we scale out. That allows us to convert underutilized office space into laboratories where we can produce cocoa and coffee.

This is fantastic, because here in West Sacramento, where my labs are located, we’re using underutilized office space with very low cost per square foot, compared to what you’d pay for a GMP facility or a site designed for large-scale mammalian cell culture.

David Brühlmann [00:22:51]:
Yeah, that's interesting, because this model could also be very compelling for emerging markets. You could put this somewhere in Africa, Asia, or Southeast Asia. That works, and people there have the competencies to run it.

Steven Lang [00:23:10]:
Absolutely. And I’m really glad you brought that up. Not only can we co-localize these bioreactors because they’re so inexpensive, but we can also onshore production that historically hasn’t happened in Europe or the United States—particularly coffee and cocoa, which are restricted to regions around the equator.

In the U.S., the only places we can really grow coffee or cocoa are Puerto Rico and Hawaii, and that’s not enough. Our vision is to build not just the cell lines, but also the processes and infrastructure that allow us to deploy these production units anywhere in the world—co-localized with chocolatiers or manufacturers, right next to their facilities.

That also enables the creation of more biomanufacturing jobs. All of these are what I’d call positive externalities that come from focusing on low-CAPEX, low-OPEX biomanufacturing for products people genuinely want—and frankly, people are addicted to chocolate and coffee.

David Brühlmann [00:24:16]:
Yeah. And I think this is just the beginning, because you can produce all kinds of products in these cell culture systems.

Steven Lang [00:24:23]:
Yeah, absolutely. There are already plenty of precedents. Plant cell culture has been around for a long time. There are drugs being produced—at least four that I know of—from plant cell culture. There are also animal vaccines, as well as a wide range of nutraceuticals, cosmetic ingredients, and specialty compounds produced using plant cell culture.

David Brühlmann [00:24:44]:
That’s just the beginning of our conversation with Steven Lang. We've explored the foundations of cellular agriculture and the bioprocessing challenges of growing cacao in bioreactors. In part two, we'll dive into the economics, the scalability, and what this means for the future of food production.

If you’re finding value in this episode, please leave us a review on Apple Podcasts or your favorite platform. It helps other biotech scientists like you discover these conversations. We’ll see you in part two.

All right, smart scientists—that’s all for today on the Smart Biotech Scientist Podcast. Thank you for tuning in and joining us on your journey to bioprocess mastery. If you enjoyed this episode, please leave a review on Apple Podcasts or your favorite podcast platform. By doing so, we can empower more scientists like you.

For additional bioprocessing tips, visit us at smartbiotechscientist.com. Stay tuned for more inspiring biotech insights in our next episode. Until then, let’s continue to smarten up biotech.

Disclaimer: This transcript was generated with the assistance of artificial intelligence. While efforts have been made to ensure accuracy, it may contain errors, omissions, or misinterpretations. The text has been lightly edited and optimized for readability and flow. Please do not rely on it as a verbatim record.

Next Step

Book a free consultation to help you get started on any questions you may have about bioprocess development: https://bruehlmann-consulting.com/call

About Steven Lang

Steven Lang is the Head of R&D, Bioprocess, and Analytics at California Cultured, where he leads the development of sustainable cocoa and coffee produced directly from plant cells. He brings over 20 years of experience in cell culture and biomanufacturing from the biopharmaceutical industry, including roles at Genentech and Johnson & Johnson.

Steven is passionate about applying scientific rigor and scalable bioprocessing to build more resilient and sustainable food systems.

Connect with Steven Lang on LinkedIn.

He is also a biotech technology innovation coach, technology transfer leader, and host of the Smart Biotech Scientist podcast—the go-to podcast for biotech scientists who want to master biopharma CMC development and biomanufacturing.  

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