When foam appears, most air-in-oil discussions begin. deepfluid argues that this is precisely where they begin too late.
Ahead of Lubricant Expo Europe 2026, we spoke with David Placzek, Business Lead and Dr. Lukas Hafner, Tech Lead at deepfluid, about the industry’s “late-stage mindset”, why air should be treated as a dynamic contamination state, what hidden bubble populations reveal, and how the AIR Cycle and one shared air measurement language can create Air-in-Oil Intelligence from lab to field.
deepfluid describes the conventional foam-focused view of air-in-oil as a “late-stage mindset”. Why?
Because by the time foam becomes visible, the air-in-oil story is already under way. Foam is the headline we notice, but it is not the first event.
Air has entered through agitation, turbulence, pressure changes, return flows or component interactions and churning effects. Below the surface, bubbles may break up, combine, remain entrained or release again as conditions change—affecting fluid and system behavior before visible foam appears.
deepfluid therefore treats air-in-oil as a dynamic, measurable contamination state, changing by the position of the measurement and current process parameters when measured. The issue is not foam versus bubbles, but whether we observe only the outcome or follow air from the moment it enters the oil.
If foam, single air-release or air-content values do not tell the whole story, what does bubble-level information add?
Clearly defined values—air release in minutes, air content in vol-% or foam tendency and stability—remain important references, but compress a dynamic process into endpoints.
Two fluids may show similar values while containing different bubble populations. Bubble size, size distribution, oil-air contact surface/interfacial area, interaction and retention reveal what sits behind the number.
Especially the oil-air contact surface adds another dimension: the same air volume in many small bubbles creates a larger interface than in fewer large bubbles. This bubble-level metric provides a meaningful variable for correlation with dedicated oxidation and ageing analyses.
Bubble-level information therefore explains not only how much air is present, but in what form, for how long and under which conditions.
deepfluid introduces the AIR Cycle as a new framework. How does it change the way air-in-oil behaviour is understood and interpreted?
AIR stands for Air Intake, bubble Interaction and Retention, and Release. It shifts attention from an isolated result to air’s complete journey through a fluid and system.
Air Intake examines where and under which conditions air enters, how quickly air content builds, how much becomes entrained and which peak is reached within a defined test duration or operating regime.
This creates an important evaluation phase for formulation and fluid selection. Two oils exposed to identical aeration may reach different air levels, bubble populations and starting content for air release measurement.
Interaction and Retention describes how bubbles interact with each other and the fluids in terms of how they change in size, contact surface or remain suspended.
Release describes how efficiently the air leaves. Air Release becomes more meaningful when interpreted in relation to the Air Intake, the reached peak and bubble state that preceded it.
The AIR Cycle is therefore not another single parameter, but a framework for comparing fluids, formulations, system changes and operating regimes.
Why is bubble-level analysis the missing link between air-release and foam behaviour—and how does it make their evaluation more relevant for formulators and engineers?
ISO and ASTM methods remain essential reference standards, providing established and comparable endpoints such as air-release time, foam tendency and foam stability. Bubble-level analysis builds on this foundation by adding a dynamic and complementary intelligence layer: particularly for R&D and formulation work, it reveals how subsurface bubble populations evolve and how their behavior relates to foam formation, stability and decay.
Formulators can investigate whether behavior may be associated with the base oil, additive chemistry or their interaction. Engineers can relate the same evidence to temperature, pressure, flow, component design and operating regimes.
Air Release describes how air leaves the oil, foam testing what becomes visible at the surface, and bubble-level analysis what happens between them. The aim is to extend established methods with state-of-the-art optical measusrement technology, not replace them.
How does deepfluid combine laboratory analysis, system testing and field measurement to create Air-in-Oil Intelligence from Lab to Field?
By treating them not as separate measurement worlds, but as one connected evidence path.
Imagine two formulations being compared under controlled conditions with our Air-in-One Lab Analyzer. Alongside AIR and foam behaviour, it captures bubble distributions, oil-air contact surface and their development over time. An Evidence Snapshot connects selected KPIs with the visible bubble population and test context.
The selected fluid can then move into a component, gearbox or hydraulic test system. Our Optical Fluid Sensor shows how cold starts, speed, load, pressure or design changes affect the AIR Cycle. In field operation, the same framework reveals whether the established pattern remains stable or shifts.
So the laboratory creates the controlled reference, testing explains system response and field measurement reveals real operation. The environments are not identical, but the digital layer makes their evidence traceable and comparable through one shared air-measurement data language.
How can one shared air-measurement data language improve R&D, formulation and engineering—and close the Evidence Loop from field back to lab?
It means using consistent definitions, units, metadata and visualizations, so bubble distributions, air-content trends, oil-air contact surface and operating events remain understandable across development stages.
Today, this evidence is often fragmented. A laboratory may use a density-based method, testing may use dielectric or conductivity signals, while a laser-based particle counter in the field may register bubbles indirectly or as interference. Each method can add value, but the outputs do not inherently describe the same physical variables or deliver the same reliability in terms of measured values.
deepfluid adds a common optical evidence layer. The AIR Cycle provides the interpretation framework; the Bubble-Level Matrix carries comparable metrics such as air content, bubble count, size distribution, oil-air contact surface, Intake, Retention and Release. Evidence Snapshots preserve what was measured, when and under which conditions.
A field deviation can therefore be compared with a laboratory baseline, investigated in testing and translated into a formulation or engineering question. A modified formulation, component design or operating strategy can then be validated and returned to the field with a traceable evidence chain.
This is not a new industry standard, nor does it imply identical environments. It allows additive suppliers, formulators, laboratories, Tier 1 and Tier 2 suppliers, OEMs and operators to work from the same air-behaviour story.
That is deepfluid’s 360-degree approach: a closed Evidence Loop from lab to testing to field and back again.
deepfluid will make its Lubricant Expo debut with it’s first product launches and two Innovation Awards entries. What can visitors expect to see and experience?
We deliberately selected Lubricant Expo Europe to launch our Air-in-One Lab Analyzer and the Optical Fluid Sensor because it brings together those who formulate fluids, develop components, validate (fluid) systems and operate equipment.
Our goal is to broaden the industry’s perspective: instead of developing an application or formulating a fluid and selecting or judging a lubricant based on a single air-release, air-content or foam value, we want to understand why it behaves the way it does—and turn that evidence into better decisions across R&D, formulation, validation and engineering, from lab to field. That is the shift from isolated test results to Air-in-Oil Intelligence.
At Stand 785, visitors can experience our from-lab-to-field approach live: optical bubble measurement, Evidence Snapshots and the connection between AIR and foam—from controlled analysis to operational measurement.
Both solutions are entered in the Innovation Awards. Visitors can discover them in the Awards Gallery (and vote for us). Should deepfluid reach the finalist stage, we look forward to presenting our technology and Air-in-Oil Intelligence approach to a broader audience during the pitch.
deepfluid will exhibit at Lubricant Expo Europe 2026 from 15–17 September in Hall 10 at Messe Düsseldorf, Germany. Visit deepfluid at Stand 785.
