Scraped Surface Heat Exchanger in Chocolate Spread Processing
The scraper heat exchanger is the core equipment for precise temperature adjustment, cooling, crystallization and continuous cooling in chocolate sauce production. It plays a decisive role in the taste, appearance, stability and shelf life of the final product.
Below, we will elaborate on its functions from several core aspects:
- 1. Core Function: Precise tempering of cocoa butter
This is the most important and irreplaceable role of the scraper heat exchanger in chocolate production.
Cocoa butter in chocolate sauce is a polymorphic fat, meaning it can form crystals of various types (I to VI). Among these, only type V crystals (β-V crystals) are ideal. This crystal structure is stable and enables the chocolate to:
Have a bright appearance (not dull).
Make a crisp cracking sound.
It melts quickly in the mouth, bringing a smooth texture.
Long shelf life and less prone to frosting.
How does a scraper heat exchanger achieve temperature adjustment:
The temperature adjustment process is essentially an accurate control process of heating, cooling, and slightly reheating chocolate sauce, with the aim of promoting the formation of a large number of stable V-shaped crystals.
Complete melting: The chocolate is heated to 45-50°C to completely melt all its fat crystals.
Cooling and crystallization (the core step in the scraper heat exchanger): The melted chocolate is pumped into the scraper heat exchanger. The heat exchanger is rapidly cooled by the cooling medium (such as cold water or refrigerant) in the jacket.
Precise temperature control: The equipment can precisely cool the chocolate to the temperature that promotes the formation of V-shaped crystals (typically around 27-28°C). At this temperature, both unstable and stable crystals begin to form.
Continuous Scraping: The high-speed rotating scraper constantly scrapes off the chocolate cooled on the cylinder wall and mixes it with the hot chocolate at the center. This ensures:
Uniform heat exchange: Avoid local overcooling or overheating, with highly uniform temperature.
Shearing effect: Mechanical shearing force helps to "prune" unstable crystals and provides nuclei for the formation of stable crystals (V-shaped).
Reheating (optional, sometimes in subsequent steps): The chocolate coming out of the scraper heat exchanger is slightly reheated to a working temperature of 29-31°C to melt the unstable crystals, leaving only the stable V-shaped crystals as "seeds".
Without scraper heat exchangers, traditional temperature control methods are very time-consuming, difficult to control and not suitable for large-scale continuous production.
- 2. Efficient and uniform cooling
Even without complex temperature adjustment processes (such as for certain chocolate sauces that do not require temperature adjustment), the scraper heat exchanger is an efficient cooling device.
Chocolate sauce has high viscosity and poor heat conductivity: When chocolate sauce cools, it becomes very thick and is a poor conductor of heat. If a regular cooling tank is used, the center part cools extremely slowly, while the part near the tank wall cools excessively and forms lumps.
The function of the scraper: The scraper continuously scrapes the cylinder wall, breaking the thermal resistance layer and forcing all materials to uniformly contact the cold wall, thereby achieving rapid and uniform cooling. This is crucial for enhancing production efficiency and ensuring consistent product quality.
- 3. Key to Continuous Production
The scraper heat exchanger is designed for continuous operation. Liquid chocolate is pumped in at one end, precisely tempered and cooled, and then continuously flows out from the other end, directly entering the next process (such as mold filling, coating or packaging).
High efficiency: Compared with the traditional intermittent temperature-regulating cylinder, continuous production greatly increases the output capacity.
Stability: Once the parameters are set, the state of the chocolate flowing out (temperature, viscosity, and crystallization) is very stable, ensuring a high degree of consistency between batches of products.
- 4. Applicable to a variety of products
In addition to standard chocolate, the scraper heat exchanger is also highly suitable for processing products with a high proportion of particulate matter, such as nut chocolate spreads, or heat-sensitive composite coatings and candy fillings, as it effectively prevents particle sedimentation and ensures uniform heat exchange.
Summary: Core Advantages of Scraped Surface Heat Exchangers
Advantages Concrete Manifestations
High Product Quality Products have good gloss, smooth texture, stable structure, and are less prone to frosting.
Controllable Production Process Parameters such as temperature, cooling rate, and viscosity can be precisely controlled, enabling automation.
High Production Efficiency Continuous production, fast cooling/temperature adjustment, suitable for large-scale industrial manufacturing.
Excellent Product Consistency Each batch of products can meet the same quality standards, eliminating errors from manual operations.
Flexible Application Parameters (temperature, speed) can be adjusted to accommodate different chocolate formulas or similar high-viscosity products.
Conclusion:
In the modern chocolate sauce (and chocolate products) industry, the scraped surface heat exchanger has evolved from an "optional equipment" to a core standard device for achieving high-quality and high-efficiency production. It perfectly resolves the most critical temperature adjustment and cooling challenges in chocolate processing, serving as the technical cornerstone for ensuring chocolate's captivating luster and delightful texture.
Post time: Sep-24-2025