The blast chiller has become an essential piece of equipment in professional patisserie and food production. Indeed, it enables a product’s core temperature to be reduced from +63°C to +10°C in less than two hours, a regulatory requirement imposed by the HACCP method. However, one aspect is often overlooked: the mould used is also subjected to this sudden thermal shock. Yet not all materials withstand these repeated temperature fluctuations in the same way.
In practical terms, an unsuitable mould may crack, warp or lose its properties over the course of repeated hot-cold cycles. This guide explains how a blast chiller works, what happens to your moulds during thermal shock, and how to choose a material capable of withstanding these stresses in intensive production.
OBJECTIVE To understand the impact of thermal shock from a rapid cooling chamber on your moulds and to choose a material that can withstand repeated hot-cold cycles.
What is a blast chiller and why use one?
A blast chiller is a refrigerated chamber with very high cooling capacity, capable of rapidly lowering the temperature of a hot product using forced circulation of cold air. Indeed, the forced-air temperature is generally between -15 and -20°C, which allows for much faster cooling than a conventional cold store. As such, the blast chiller meets a specific regulatory requirement regarding food safety.
In practical terms, the regulations impose an obligation to achieve a specific result. According to the decree of 21 December 2009, cooling must be carried out in such a way that the core temperature of the product does not remain between +63°C and +10°C for more than two hours. Indeed, this range is referred to as the ‘danger zone’ in HACCP, as this is where pathogenic bacteria multiply most rapidly. Consequently, passing through this stage quickly is a critical factor in ensuring food safety.
Positive cooling and deep-freezing cycle
A cold store generally offers two types of cycle. Firstly, positive cooling brings the core temperature of the product down from +63°C to +10°C (or even +3°C) in less than two hours, for short-term storage in the refrigerator. Next, the deep-freezing cycle lowers the core temperature from +63°C to -18°C, usually within four hours, for long-term storage. Furthermore, once the +10°C threshold has been reached, the products must be stored in a chamber at between 0°C and +3°C.
📌 Key point: it is the sudden temperature change that causes damage, not just the cold
A mould that is placed hot into a cold room undergoes significant thermal shock within a few minutes. In fact, it is not the cold alone that weakens a material, but the magnitude and abruptness of the temperature change, repeated cycle after cycle. Consequently, an unsuitable material may gradually crack or warp, whereas a material designed to withstand these stresses remains stable.
What happens to your moulds during thermal shock
When a mould rapidly transitions from a high temperature to a sub-zero temperature, the material is subjected to internal mechanical stresses. This is because most materials expand when heated and contract when cooled. Consequently, an abrupt transition from hot to cold causes rapid contraction, which can weaken a material that is unsuitable for the application.
In practical terms, during repeated cycles in intensive production, an unsuitable material can cause several problems. Firstly, micro-cracks may appear and worsen over the course of the cycles. Secondly, gradual deformation can affect the precision of the mould cavities. Furthermore, a porous or degraded material retains more residue, which poses a hygiene issue. Thus, the choice of mould material is no minor detail: it determines the service life of the mould and the consistency of production.
The material’s temperature range is the key criterion
To withstand both baking and the cooling phase, a mould must cover a wide temperature range. Indeed, if the material is used close to, or beyond, its limits, it will degrade more quickly. This is why you must check that the temperature range specified by the manufacturer covers your entire process, from baking temperature right through to deep-freezing.
Which materials can withstand thermal shock in a blast chiller?
Not all mould materials perform equally well when faced with thermal shock. In practice, the key criteria are the temperature range they can withstand and their ability to withstand repeated hot-cold cycles without deteriorating.
Food-grade platinum-cured silicone is one of the materials best suited to these conditions. It retains its flexibility at low temperatures, making it easy to remove products from the mould even after deep-freezing, and it withstands high temperatures during cooking. This means that products can be cooked and then transferred directly to the blast chiller without needing to be moved to another container. Furthermore, its non-porous surface minimises the retention of residues, which is a key benefit for hygiene in production.
📌 What to check before buying
Always check the temperature range specified by the manufacturer and ensure it covers both your cooking temperature and your freezing temperature. A mould used within its specified temperature range will last longer and retain its properties cycle after cycle. Also ask for the material data sheet and food safety certification.
The Silmaé solution for repeated hot-cold cycles
Maé Innovation offers several ranges of moulds manufactured in France for professional use. Indeed, for intensive hot-cold cycles and use in blast chillers, the Silmaé range made from platinum-cured silicone is the most suitable: it covers a temperature range from -40°C to +280°C, which encompasses both baking and deep-freezing in blast chillers.
In practical terms, this wide range allows for consecutive hot-cold cycles without transferring the product. Thus, a dessert can be baked or set in the mould and then transferred directly to the blast chiller in the same mould, which simplifies the process and minimises handling. Furthermore, platinum-cured silicone retains its flexibility at low temperatures, making it easier to demould frozen products without breakage. For other production requirements, Maé also offers the Fibermaé (siliconised fibreglass) and thermoformed ranges, with properties tailored to each application.
- Temperature range -40°C to +280°C: suitable for baking and deep-freezing
- Food-grade platinum silicone: stable and certified for food contact
- Flexibility at low temperatures: easy release of frozen products
- Non-porous surface: improved hygiene and easy cleaning
- Made in France, EU and US certified, bespoke options available
This resistance to hot-cold cycles is particularly useful for frozen desserts and deep-frozen products. To find out more, see our guide to silicone moulds for frozen desserts. Furthermore, in high-volume bakery production, these same requirements apply, as detailed in our article on industrial bakery.
Do you use a blast chiller?
Silmaé moulds from Maé Innovation can withstand hot-cold cycles from -40°C to +280°C. Made in France, EU and US food-grade certified, available from our catalogue or made to measure.
Summary: mould and rapid cooling chamber
FAQ: Blast chiller and moulds
Do you operate with intensive hot-cold cycles?
Maé Innovation’s Silmaé range, made from platinum-cured silicone, withstands temperatures from -40°C to +280°C, allowing you to move products directly from the oven to the blast chiller without transfer. Maé manufactures several ranges of EU and US food-grade certified moulds in France, available from the catalogue or made to measure.
