Freezing operations are key processes for frozen dough and frozen batter manufacturers. Freezing dough allows bakers to accumulate and store inventory. This is particularly important for holidays and summer times where the demand for bread, buns and other bakery products peaks.
Dough and batter freezing has become a supply chain and logistics game changer. Freezing extends the shelf-life of dough, allowing bakers to reach distant markets and continue to grow their business.
How does thermal profiling help?
Frozen dough suppliers recognize that in order to offer a high quality product, they must ensure dough pieces are getting the optimum freezing treatment.
Several aspects of the freezing operation require close control and attention to guarantee intended dough shelf-life and excellent texture of the baked goods. Thermal profiling can help ensure that the freezing process is successful and process parameters are being properly monitored and controlled.
Key operational points during dough and batter freezing include:
- Freezing cycle time
- Freezer temperature (set point)
- Rate of temperature decrease (slope)
- Internal temperature of product (key if formulation changes are done)
Since the baking and freezing process are both unit operations involving heat transfer and changes in state, a thermal profile can be run to measure the internal product temperature, looking closely at changes that take place in the product during freezing.
In the freezing process, the product loses sensible heat to the cold surroundings and starts to get colder; starting from regular dough mixing temperatures (75–80°F) and finishing with a temperature of –0.4 to –9.4°F (–18 to –23°C). Then, the product goes through the critical temperature zone, i.e. temperature range in which the product’s core reaches and surpasses the freezing point (giving up latent heat) and finally reaches final temperature.
Product formulation and freezing process: a key relationship
Freezing doughs and batters is as crucial for finished product quality as the baking step. Here, thermal profiling allows for a controlled freezing operation. Presence of water (flour hydration), sugars, salt and other enriching ingredients like fats and eggs, all affect the freezing time and energy consumption.
Solutes in an aqueous solution lower the freezing point of water below its normal value of 32°F (0°C). In bakery products, the higher the concentration of sugars, salt, fats, polysaccharides and proteins, the lower the freezing point will be. This means, that more freezing time is needed and more energy must be expended to achieve a final temperature. If faster results are needed, then the freezer settings must be more severe.
Rich formulas will have a different freezing recipe than that of a lean formulation. This explains why a croissant may take longer to freeze than a bun (of similar geometry and thickness) or why a loaf of pan bread may take shorter to freeze than a pound cake of similar loaf dimensions.
Products that are too porous (open cell structure) exhibit poor thermal conductivity, hence taking longer than normal to reach frozen temperatures.