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What Actually Survives
85°C Conditioning?

September 2026 · Technical Insight · 9 min read

Short answer: the molecule usually survives. What often does not survive is the delivery system around it — the carrier, the particle size distribution, and the assumption that a dosage measured in kilograms describes what reaches the animal.

Most feed sweetener chemistries in commercial use are thermally robust in dry form. That makes "heat stable" a weak differentiator and a poor buying criterion. This guide covers what actually changes during conditioning and pelleting, how carrier choice quietly moves your cost per tonne, why particle count is a more useful specification than inclusion rate, and how to measure retention on your own mill floor.

Key points

  • Sodium saccharin, neotame, sucralose and NHDC are all substantially heat tolerant in dry form. Aspartame is not and should not be specified for pelleted feed.
  • Temperature alone is not a thermal load. Residence time and die friction matter as much; a retention figure quoted without them is not comparable between mills.
  • A carrier can be 60-90% of what you buy and ship, and it absorbs moisture in a humid warehouse. That is a real cost, not a technicality.
  • At low inclusion rates, particle count per gram governs bite-to-bite uniformity more than the dosage on the batch sheet does.
  • Compare suppliers on cost per tonne of finished feed at an equivalent sensory endpoint, never on price per kilogram.

1. What conditioning and pelleting actually do

Three distinct stresses act on an additive between the mixer and the cooler, and they fail products in different ways.

Steam and moisture

Conditioning injects steam to plasticise the mash. Moisture and heat arrive together, which matters because many additives are far more vulnerable to hydrolysis in hot wet conditions than to dry heat at the same temperature. A stability figure generated in a dry oven does not describe a steam conditioner.

Thermal load, not temperature

Thirty seconds at 85°C and three minutes at 85°C are different exposures, and mills routinely quote only the temperature. Add die friction — which can push material temperature meaningfully above the conditioner reading — and two mills reporting the same conditioning temperature can be subjecting an additive to noticeably different loads. When requesting retention data, specify temperature, residence time and die configuration together.

Mechanical stress

This is the one most often overlooked. Between mixing and the die, material is conveyed, augered, and forced through a compression zone. Soft or friable carriers abrade; the fine dust that results segregates differently from the intact granule and can end up concentrated somewhere other than in the pellet. The active is chemically intact and still in the wrong place.

2. Chemistry: less of a differentiator than it appears

SweetenerDry-form heat behaviourPractical note for pelleted feed
Sodium saccharinRobust to normal conditioning temperatures Long-standing workhorse. Withdrawn from the EU market for piglets by Reg. (EU) 2024/1727 (a use-up period for compound feed ran to 11 July 2026) — a regulatory constraint, not a thermal one
NeotameRobust in dry form Very high sweetness intensity, so inclusion mass is small and dispersion becomes the limiting factor
SucraloseStable in dry state over normal conditioning ranges Behaviour is more sensitive to matrix and moisture than to peak temperature alone
NHDCRobust in dry form Slow onset with a lingering profile; usually blended rather than used alone
AspartameDegrades well below typical conditioning temperatures Not appropriate for pelleted feed

Since four of the five behave acceptably, "thermally stable" describes most of the market. It is necessary, not distinguishing. The questions that actually separate products are what carries the active, how finely it is distributed, and what it costs per tonne of finished feed.

3. The carrier question

Because high-intensity sweeteners are used at very low mass, most commercial products adsorb the active onto a carrier — silica, maltodextrin, or a mineral base. This is a legitimate engineering choice: it makes a gram-scale active meterable at tonne scale. It also has consequences that rarely appear on a datasheet.

ConsequenceWhy it happensWhat it costs you
Freight and duty on inert massCarrier is typically the majority of product weight You ship, clear and store material that does not sweeten anything
Moisture pickupMany carriers are hygroscopic Caking and flow problems in humid warehouses; possible loss of dispersion
Abrasion and segregationSofter carriers break down under mechanical stress Active ends up unevenly distributed even when chemically intact
Opaque comparisonActive percentage is rarely published Price per kilogram becomes uninterpretable between suppliers

The alternative is a carrier-free micro-granular form, where the active itself is produced at a particle size fine enough to disperse without a substrate. That removes the ballast, but transfers the burden onto particle size distribution — which is why particle count becomes the specification worth asking for. We covered the economics of this in more detail here.

4. Why particle count beats inclusion rate

Consider a sweetener dosed at 100 g per tonne. One tonne of feed is 1,000,000 g, so the active is roughly one part in ten thousand by mass. Whether that reads as uniform sweetness or as random variation depends entirely on how many discrete particles that mass is divided into.

If the mass is carried by relatively few coarse particles, some portions of feed contain several and others contain none. The batch sheet still says 100 g per tonne; the animal experiences something else. Divide the same mass into far more, far finer particles and every mouthful trends toward the average. This is why particles per gram is a more decision-relevant number than inclusion rate, and why two products at identical dosage can behave differently in a feeding trial.

Dissolution speed matters for the same reason in liquid applications — drinking-water dosing and milk replacer give the particle very little time to go into solution before the animal drinks.

5. A retention test you can run at the mill

  1. Sample three points. Post-mixer mash, post-conditioner mash, and cooled finished pellet, from the same production run.
  2. Take enough material. At low inclusion rates, sampling error will exceed the effect you are trying to measure unless samples are large and taken as multiple increments.
  3. Assay the marker. Have a laboratory quantify the sweetener's marker compound at each stage. The mash-to-pellet ratio is your true retention.
  4. Check uniformity, not just retention. Take ten sub-samples of finished pellet and assay each. The coefficient of variation tells you about dispersion, which is the failure mode retention testing alone will miss.
  5. Repeat with a second product. Absolute numbers depend on your assay and your process. Relative numbers between two products, run the same day on the same line, are what should drive the decision.

If a supplier declines to support this kind of test on a trial quantity, that is worth knowing before a purchase order rather than after one.

6. Where SILSEP sits on this

GradeFormPublished figures
Feed Sweetener VS7188 Carrier-free micro-granular, 100% active 76,000,000 particles per gram; dissolves in 3 seconds; tolerates 85°C+ steam conditioning and pelleting
Feed Sweetener VS3965 Neotame + sodium saccharin system Sucrose-like profile; 60-180 g/T in complete feed; 18-month shelf life. Contains sodium saccharin (E 954(iii)) — withdrawn for piglets in the EU by Reg. (EU) 2024/1727; verify status for your species and market

We publish particle count and dissolution time because they are the numbers that determine whether a low-dose additive behaves consistently, and because a heat-stability adjective on its own does not distinguish one product from another in this category. If you send us your conditioning temperature, residence time and target market, we will tell you which grade fits — and say so plainly if neither does.

Related reading: how long a palatant actually lasts in tropical storage, which covers the storage half of the same problem.

Frequently asked

In dry form, the high-intensity sweeteners used in feed - sodium saccharin, neotame, sucralose and NHDC - are all substantially more heat tolerant than aspartame, which degrades well below typical conditioning temperatures and should not be specified for pelleted feed. But molecular stability is only half the answer: the physical form matters as much as the chemistry. A thermally stable molecule sprayed onto a soft carrier can still be lost to abrasion, segregation and moisture pickup before it reaches the die.

Both, and they trade against each other. Thirty seconds at 85°C is a different thermal load from three minutes at 85°C, yet mills often quote only the temperature. When you ask a supplier for retention data, give them your conditioning temperature, residence time and die specification together. A retention figure quoted without residence time is not comparable between mills.

Many feed sweeteners are an active compound adsorbed onto a carrier - typically silica, maltodextrin or a mineral base. The carrier makes a low-dose active easier to handle and meter, which is legitimate. The cost is that you buy, ship, store and pay duty on material that does not sweeten anything, and that carrier can absorb moisture in a humid warehouse. A carrier-free product delivers the active without the ballast, but requires the particle size distribution to do the dispersion work instead.

Not by price per kilogram. Convert both to cost per tonne of finished feed at the dosage each supplier recommends for an equivalent sensory endpoint. A product at twice the price per kilogram used at a third of the dosage is cheaper in the only unit that matters. If a supplier cannot give you a dosage for a defined sweetness endpoint, you cannot make this calculation and should treat that as information about the supplier.

At 100 g per tonne, each animal's daily ration contains a very small mass of sweetener. If that mass is carried by relatively few large particles, some portions of feed receive several particles and others receive none. Sweetness then varies bite to bite, and the average dosage on the batch sheet stops describing what any individual animal actually tastes. Finer, more numerous particles at the same mass give a more uniform result, which is why particle count per gram is a more useful specification than inclusion weight alone.

Post-pellet liquid application avoids thermal loss entirely and is common for heat-sensitive actives. The trade-offs are capital cost, coating uniformity, and the fact that a surface-applied sweetener is more exposed to abrasion and to moisture during storage than one distributed through the pellet. For a mill that already has post-pellet application, it is worth evaluating. For one that does not, specifying a conditioning-stable dry grade is usually the cheaper route.

See Feed Sweetener VS7188   Request a trial quantity

Last updated: 3 September 2026

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