Eutectic products : gel packs or eutectic plates?

12 January 2026 by Edina GÁLFI

Understanding the impact of composition on performance, safety, and applications

In cold-chain logistics, the term “eutectic cooling” is often used as if it referred to a single, homogeneous solution. In reality, this label covers very different products whose performance, autonomy, quality of cooling delivery, and even operational safety depend directly on one key factor : their chemical composition.

Between gel packs and high-performance technical eutectic plates, the differences are substantial. These differences are far from anecdotal, they directly determine cold-chain reliability, regulatory compliance, equipment durability, and environmental impact.

Let’s take a closer look.

1. Scientific reminder : what is a eutectic product ?

A eutectic product is a thermal storage system based on the phase change of a solution formulated to melt at a precise temperature.

During this phase change (solid → liquid), the solution absorbs thermal energy in the form of latent heat, without any significant change in temperature.

Temperature regulation is therefore achieved naturally, without a motor, without a compressor, and without refrigerants.

However, this performance depends entirely on :

the nature of the liquid,
its formulation,
its chemical stability,
and its containment.

Better understand

2. Gel packs : simplicity, low thermal inertia, and inherently limited applications

Gel packs are often the first solution that comes to mind for insulated transport. Their popularity stems from their simplicity, low cost, and immediate availability. Yet behind this apparent convenience lie structural limitations directly linked to their composition and operating principle.

Composition : a deliberately simple formulation

Gel packs are generally made from a basic mixture combining:

water, which represents the majority of the mass,
a polymer-based gelling agent (often polyacrylate or similar),
sometimes antifreeze additives, preservatives, or colorants.

This formulation serves a single main purpose : turning a liquid into a stable gel that is easy to handle and inexpensive to produce.
It is not designed to provide fine thermal regulation or high thermal inertia, unlike more advanced eutectic solutions.

The resulting gel is not a eutectic solution in the strict sense:

it does not have a single, precise melting point,
but rather a relatively wide transition range, which directly impacts thermal performance.

Impact of composition on thermal performance

Limited thermal autonomy

The amount of energy stored in a gel pack relies almost entirely on the latent heat of fusion of water, which is relatively modest.
The gelling polymer does not meaningfully contribute to thermal storage; it merely structures the liquid.

Direct consequences:

the gel pack melts quickly when exposed to heat input,
autonomy is short and difficult to predict,
cooling capacity is depleted within a few hours, or even less depending on conditions.

This makes gel packs unsuitable for long transits or scenarios involving repeated openings.

Poorly controlled and imprecise temperature

Due to the absence of a precise eutectic formulation, gel packs do not melt at a single temperature.
The solid → gel → liquid transition occurs over a broad temperature range, resulting in:

fluctuating temperatures inside the container,
excessive cooling at the beginning of the cycle,
followed by rapid temperature rise once the gel has melted.

This behavior makes gel packs poorly suited to strict requirements such as:

pharmaceutical ranges (+2 °C / +8 °C),
products sensitive to thermal shock,
thermal stability audits.

Heterogeneous cooling delivery

The cooling provided by a gel pack is rarely “smoothed.” Typically, one observes:

an initial cold peak (ice-pack effect),
followed by a rapid, non-linear decline.

This uneven cooling can cause:

partial freezing of products,
ambient temperature instability,
loss of control over the actual duration of protection.

For professional applications, this unpredictability represents a significant operational risk.

Safety and recyclability : often underestimated issues

Potential hazards of the liquid

The gelling agents and additives used in gel packs are not always designed for food or pharmaceutical use.
In the event of leakage:

the gel may be irritating to skin or mucous membranes,
it may be incompatible with product contact,
some components may be classified as non-inert.

This effectively excludes gel packs from many regulated logistics chains.

Limited recyclability

The water–polymer mixture is particularly difficult to recover:

the liquid is generally not recyclable,
the container is often contaminated,
separating components is costly or impossible.

In practice, most gel packs end up as non-recoverable waste, significantly impacting environmental performance, especially when used in large volumes.

Gel packs are simple and economical solutions, but their limitations are directly tied to their composition.
They should not be considered equivalent alternatives to eutectic plates, but rather as occasional solutions for applications with low thermal requirements.

In professional cold chains, where stability, safety, and durability are critical, gel packs very quickly reach their physical limits.

3. Eutectic plates : the industrial reference solution

Unlike simple solutions such as gel packs, eutectic plates are the result of true thermal engineering. They are not designed as consumables, but as structural components of the cold chain, intended to operate reliably, repeatedly, and safely over thousands of cycles.

Composition: high-precision formulation

Eutectic plates rely on precisely formulated eutectic solutions whose chemical composition is designed to meet several requirements simultaneously:

achieving a highly targeted phase-change temperature (e.g., +4 °C, +2/+8 °C, –21 °C),
ensuring high phase stability without component separation,
maintaining consistent thermal properties over time.

These solutions consist of complex mixtures (water, specific salts, technical alcohols, or selected organic compounds), with proportions carefully adjusted to obtain:

a narrow melting point,
high latent heat,
controlled melting kinetics.

Chemical stability is a key factor: components are selected to avoid degradation, uncontrolled crystallization, or performance loss after hundreds or even thousands of freeze–thaw cycles.

In the most demanding applications, the liquids used are:

non-toxic,
non-corrosive,
sometimes food-grade, to meet pharmaceutical and food-sector regulatory constraints.

The performance of a eutectic plate is therefore never accidental, it is inseparable from chemical formulation and the industrial expertise behind it.

Conclusion

Behind the generic term eutectic product lie solutions with vastly different levels of performance, reliability, and safety. Treating a gel pack as equivalent to a eutectic plate ignores the essential factors: chemical composition, phase-change stability, and the real ability to control temperature over time.

Gel packs address simple, short-term, low-constraint needs. They are auxiliary solutions suited to brief, non-regulated uses with low thermal stakes. Their low cost and simplicity make them convenient, but their limited autonomy, thermal instability, safety concerns, and poor recyclability make them unsuitable for demanding professional cold chains.

By contrast, eutectic plates have established themselves as the industrial standard for modern cold logistics. Designed through rigorous thermal engineering, they transform passive cooling into a true, reliable, and repeatable temperature regulation system.

They offer:

stable, controlled cooling thanks to a precisely defined melting point and smooth, progressive energy release,
predictable, scalable, and reproducible autonomy from cycle to cycle,
enhanced safety through non-toxic formulations compatible with regulated environments,
superior environmental sustainability, based on long service life, good recyclability, and reduced consumables,
optimal integration into high-performance industrial systems, whether insulated containers, multi-drop routes, or structured logistics platforms.

In a context marked by stricter regulations, increasing quality audits, growing pressure to reduce carbon footprints, and the need for controlled total costs, the choice of a eutectic product can no longer be treated as a minor operational detail.

Eutectic composition becomes a strategic lever, on par with container selection, logistics design, or transport technology.

It determines cold-chain robustness, regulatory compliance, economic performance, and environmental credibility.

Ultimately, in professional cold-chain logistics, the right eutectic product is not the one that costs the least, but the one that secures long-term performance.