When I first started formulating, I believed there must be “one right emulsifier” for every product. With time, failed batches, unstable creams and many reformulations, I realised that emulsification is never about a single ingredient. It is about balance, structure and understanding how your formula behaves as a whole.
This article is not a technical manual. It is a practical introduction based on real formulation experience.
understanding the two phasesEvery classic emulsion is built on two main parts:
- the oil phase, which contains oils, butters, waxes and lipid-soluble ingredients
- the water phase, which contains water, hydrosols, humectants and water-soluble actives
By nature, these two phases repel each other. They do not want to mix. No amount of wishful thinking will change that.
This is where emulsifiers come in.
An emulsifier works as a bridge. One part of its structure “likes” water, the other “likes” oil. This dual behaviour allows it to hold tiny droplets together and prevent separation.
Without proper emulsification, a cream is simply two liquids sharing the same jar.
emulsification is about stability, not just textureMany beginners focus mainly on texture. They want something light, rich, fluffy or silky.
Texture matters, of course. But the real goal of emulsification is stability.
A good emulsion should:
- remain homogeneous over time
- resist temperature changes
- tolerate normal handling and storage
- maintain its structure during its shelf life
A cream that feels perfect on day one but separates after two weeks is not a successful formulation.
how emulsions are formed in practiceIn most small-scale formulations, emulsification happens in two main ways:
thermal emulsification
Both phases are heated and combined at similar temperatures. This method helps solid emulsifiers melt and disperse evenly.
mechanical emulsification
High-shear mixing, blending or continuous stirring creates fine droplets and improves dispersion.
In reality, most stable emulsions use a combination of both.
Heat prepares the system. Mixing builds the structure.
why there is no “universal” emulsifierWith experience, one thing becomes very clear: emulsifier choice depends on many interacting factors.
Including:
- oil phase percentage
- type of oils and butters
- presence of waxes or fatty alcohols
- target texture
- skin or hair application
- pH range
- preservation system
An emulsifier that works beautifully in a light lotion may completely fail in a rich body cream.
That is why professional formulation is never copy-paste.
oil-in-water and water-in-oil emulsionsMost skincare products belong to one of two main families:
Oil-in-Water (O/W)
Oil droplets are dispersed in water.
These emulsions feel lighter and are common in lotions, serums and gels.
Water-in-Oil (W/O)
Water droplets are dispersed in oil.
These feel richer, more protective and are often used in barrier creams and balms.
However, real formulations are often more complex than this simple classification. Modern systems may behave somewhere in between.
about emulsifier concentrationThere is no fixed percentage that applies to every formula.
Most modern emulsifiers work within specific ranges, often between 2% and 8% of the total formula, depending on:
- oil load
- co-emulsifiers
- stabilisers
- rheology modifiers
Reducing emulsifier levels sometimes requires reinforcing the system with gums, fatty alcohols or polymers.
Formulation is always about trade-offs.
pH, preservation and compatibilityAn emulsion is not isolated from the rest of the formula.
Its stability depends heavily on:
- final pH
- preservative system
- active ingredients
- electrolyte content
Some emulsifiers perform well only in narrow pH ranges. Others lose efficiency when combined with certain preservatives.
Ignoring compatibility is one of the fastest ways to create unstable products.
solid emulsifiers, liquid emulsifiers and solubilisersIn practice, you will encounter different physical forms:
solid emulsifiers
Often supplied as flakes, pellets or pastilles.
They usually require heating and are common in creams and lotions.
liquid emulsifiers and solubilisers
Used mainly for sprays, mists and low-oil systems.
They help disperse small amounts of oils in water.
Each category serves different formulation needs. They are not interchangeable.
understanding HLB without overcomplicating ItThe HLB system describes how “water-loving” or “oil-loving” an emulsifier is.
In simple terms:
- higher values favour oil-in-water systems
- lower values favour water-in-oil systems
In modern formulation, HLB is mainly used as a guideline, not a strict rule.
Most formulators today rely more on manufacturer data and real testing than on theoretical calculations.
why testing matters more than theoryNo spreadsheet can replace physical testing.
A stable formula should be evaluated through:
- heat and cold cycles
- room-temperature storage
- visual inspection
- texture monitoring
- long-term observation
Many emulsions look perfect for weeks before they start failing.
Patience is part of formulation.
my personal approach to emulsificationAfter years of experimenting, reformulating and sometimes throwing entire batches away, I learned one simple truth:
Emulsification is controlled risk.
Every new formula is an experiment.
You reduce uncertainty with knowledge and experience, but you never eliminate it completely.
This is what makes formulation challenging and, at the same time, deeply rewarding.
looking aheadIn future articles, I will share:
- detailed reviews of emulsifiers I have tested
- natural and PEG-free systems
- cold process options
- co-emulsifiers and stabilisers
- the real role of beeswax
- common stability problems and how to fix them
Because learning emulsification is not a single lesson.
It is an ongoing process.
