Steffen Jahnke of GEA explores how the right pre-mix sets the foundation for successful plant-based homogenisation, and what scale-up really tests.
Ask a formulator what could go wrong when a plant-based drink or a meat alternative moves from the lab to the production line, and pressure, valve design and homogenisation settings are usually the first variables mentioned. Steffen Jahnke, Sales Director for Homogenization Technology at GEA Homogenizers in Germany, puts the emphasis somewhere else entirely. In his experience, the step most likely to dictate a formulation’s success happens before the homogeniser is even switched on.
“Any deviation in the pre-mix cannot be corrected later,” he says. Particle size, air content, temperature control and how thoroughly a batch is de-aerated during pre-mixing set limits that no amount of pressure or valve tuning downstream can undo. By his own ranking, it is the single most important parameter in scaling a formulation successfully – ahead of the homogeniser itself.
Any deviation in the pre-mix cannot be corrected later.”
Steffen Jahnke, Sales Director for Homogenization Technology at GEA Homogenizers in Germany
Plant-based proteins force a rethink of homogenisation settings
That emphasis reflects a wider shift in what GEA is being asked to solve. The emulsifying properties and physical stability of dairy products are well understood after decades of use, Jahnke observes, but plant-based and alternative proteins behave differently enough that formulations cannot simply be carried across. Homogenisation pressure and temperature typically need adjusting product by product to achieve the same long-term physical stability of a dairy formulation – which it delivers more or less by default. “We cannot, in most cases, one-to-one compare classical dairy products with products that contain plant-based or other proteins,” he says. “We need to adapt.”
Texture and mouthfeel result from several parameters working together rather than homogenising pressure alone. Inlet temperature and back pressure matter as much as the primary homogenisation pressure itself, Jahnke explains, because together they govern cavitation inside the homogenising valve gap. Cavitation drives microfibrillation – the breakdown of fibres that increases viscosity and releases stabilising components such as pectin from inside the plant material, generating the textural properties a developer is aiming for. Fat and other more complex components respond differently and need less cavitation, temperature or pressure than fibre systems do, so finding that balance, rather than simply maximising energy input, has to happen at lab scale, product by product.
Formulation plays a key role in successful homogenisation
When something goes wrong, establishing whether the cause is the formulation or the homogenisation is usually straightforward, Jahnke adds. Long-term instability – resulting in separation – is most often a formulation issue, traced back to inadequate emulsifying or stabilising components. A freshly homogenised sample with an incorrect particle size, by contrast, usually points to failure in the process itself: pressure, temperature, the number of homogenising stages, or the condition of the valve. Running the machine on water alone confirms whether it is hydrodynamically sound, which isolates the question quickly.
The two causes are connected, though. Stabilisation of newly created surface area, on fat droplets or other dispersed particles, depends on emulsifying and surface-active proteins being present in the formulation. “If such components are missing in the formulation, you cannot homogenise successfully,” Jahnke says. He treats formulation and homogenisation as one process to be balanced together during development – not two disciplines handed off in sequence.
If such components are missing in the formulation, you cannot homogenise successfully.”
Steffen Jahnke, Sales Director for Homogenization Technology at GEA Homogenizers in Germany
Production machines give scaleup a built-in safety margin
GEA’s laboratory range is built around that same lab-to-line trajectory: compact table-top units for testing small volumes of product, and pilot-plant machines running to 1,500 bar for small-scale production, ahead of a move to full industrial homogenisers.
Moving a formulation from a ten-litre lab unit to a full production line is not, in Jahnke’s experience, where most scaleup problems originate. Production machines typically produce a slightly smaller particle size than lab equipment, thanks to a higher Reynolds number and more efficient flow – a built-in safety margin rather than a new risk, and one that means a customer does not need to buy new equipment simply to hit a higher pressure. GEA calculates the mean shear tension in the valve gap to compare lab and production machines directly and predict expected product quality before scaleup begins.
What manufacturers do commonly underestimate, in his experience, falls into three areas. The first is the temperature rise homogenisation itself generates – roughly 2.5°C per 100 bar of pressure for water – which is harder to manage at production scale because the cooling rate differs from the lab. The second is back pressure: a lab sample collected openly into a glass vessel behaves differently from production, where 10 to 20 bar of back pressure from downstream equipment such as a cooler changes the result. The third, and by his own ranking the most significant, is the pre-mix step.
GEA stays involved long after the homogeniser ships
GEA frames its role as extending far beyond selling equipment. Support runs from training operators on laboratory homogenisers through to on-site technical service on production machines, where engineers open the valve with the customer to assess wear on moving parts. A new formulation can change how quickly those parts wear, Jahnke notes, which affects total cost of ownership (TCO) and is worth discussing with the customer ahead of scaleup, rather than after. He also describes GEA’s homogenisers as built on a modular principle that allows parts to be exchanged and machines upgraded, rather than replaced.
For product development and analysis, GEA’s Process Technology Center in Parma, Italy gives customers – startups especially, who Jahnke notes cannot always justify their own analytical instruments – access to particle size distribution, zeta potential and electron microscopy analysis, and physical stability testing, without needing an outsourced lab.
Looking ahead, Jahnke points to new homogenising valve geometries, such as the NisoX Valve, developed to adapt to specific products rather than being applied generically. The NiSo X Radial Collider®, as he describes it, spans nano-scale emulsions, breaking down solid amorphous phases in suspension, and microfibrillation – the same mechanism, optimised further, that produces the texture plant-based formulations are built around in the first place.
