Engineering the Crystal Structure of Chocolate

Summary

In this video, Rachel McKinley, a chocolatier at Purdy's Chocolatier, shares her journey from studying biochemistry to creating chocolates. She explains the importance of chocolate crystallization, particularly the beta 5 crystal structure, which gives chocolate its shine, snap, and flavor. Rachel details the tempering process, emphasizing the critical factors of time, temperature, and agitation. She also discusses the use of machines and the CTU for achieving ideal crystallization and touches on the broader topic of crystallization in confectionery, including sugar for cream-filled centers. Rachel expresses her passion for her job, which combines science, creativity, and the joy of making people happy through delicious and beautiful chocolate creations.

Takeaways

• 🍫 Rachel McKinley is a chocolatier who transitioned from studying biochemistry and microbiology to chocolate-making after a personal interest was sparked.
• 🔬 The crystallization of chocolate is crucial for its texture and flavor, with the beta 5 crystal structure being the most desirable for a shiny, snapping chocolate.
• 🥶 Proper chocolate tempering involves controlling time, temperature, and agitation to achieve the ideal beta 5 crystal formation.
• 🚫 Uncontrolled cooling of chocolate can lead to an unappealing appearance and texture, such as when chocolate is left in a warm car and then refrigerated.
• 📉 The process of tempering chocolate involves melting it to 45 degrees Celsius to eliminate undesirable crystals, then cooling it down to 27-28 degrees Celsius with agitation.
• ⏱️ Time is a critical factor in chocolate tempering, as it takes time for the correct crystalline structure to form and for the chocolate to cool from liquid to solid.
• 🌡️ A chocolate tempering unit (CTU) measures the latent heat of crystallization to ensure the chocolate is tempered within the correct temperature range.
• 🛠️ Various methods and machines are used for tempering chocolate, from small-scale manual processes to large-scale continuous systems.
• 🌿 Seed tempering or inoculation is a technique used in small-scale chocolate tempering, where chocolate with the desired crystal structure is added to melted chocolate to encourage the same structure in the new batch.
• 🍬 Confectionery involves controlling the crystallization of not only chocolate but also sugar, which affects the texture and mouthfeel of filled centers.

Q & A

What was Rachel McKinley's initial field of study before she became a chocolatier?

Rachel McKinley was initially studying biochemistry and microbiology at the University of Manitoba.

What sparked Rachel's interest in chocolate making?

Rachel's interest in chocolate making was sparked when her boyfriend bought her a fancy box of chocolates, which led her to wonder how they were made and subsequently start making chocolates at home.

What is the key factor in making beautiful chocolate according to Rachel?

The key factor in making beautiful chocolate is the crystallization of chocolate, which gives it its structure and affects its appearance, taste, and texture.

What is cocoa butter and why is it important in chocolate making?

Cocoa butter is the fat component of chocolate and is important because it gives chocolate its structure. It is a polymorph, meaning it can take on multiple shapes, with only one shape, beta 5, providing the desired shine, snap, and taste.

What happens to chocolate if it cools under uncontrolled conditions?

If chocolate cools under uncontrolled conditions, it can develop a mottled appearance and a white, swirly pattern, which is a result of the cocoa butter cooling in a state of chaos with multiple crystal structures present.

What are the three main factors to consider for achieving ideal chocolate crystallization?

The three main factors for achieving ideal chocolate crystallization are time, temperature, and agitation. These factors influence the formation of the beta 5 crystal structure.

How does the process of tempering chocolate work?

Tempering chocolate involves melting it to a high temperature to eliminate undesirable crystal structures, then cooling it under controlled conditions of movement to encourage the formation of the beta 5 crystal structure. This process is crucial for achieving the right texture and appearance in the final chocolate product.

What is seed tempering or inoculation in the context of chocolate making?

Seed tempering or inoculation is a method where chocolate that already contains the desired beta 5 crystal structure is introduced into a larger mass of melted chocolate. This helps to ensure that as the chocolate cools, it forms the correct crystal structure throughout.

How can one measure whether chocolate is properly tempered?

One can measure whether chocolate is properly tempered using a machine called a CTU (Chocolate Tempering Unit), which measures the latent heat of crystallization. If the reading is within a certain range, it indicates that the chocolate has been tempered correctly.

Why is controlling crystallization important in confectionery beyond just chocolate?

Controlling crystallization is important in confectionery beyond chocolate because it affects the texture and mouthfeel of other products like cream-filled centers. By managing the crystallization of sugar, for example, one can create a smooth and creamy texture that enhances the overall sensory experience of the confectionery.

How does Rachel describe her job as a chocolatier?

Rachel describes her job as a chocolatier as the best in the world because she gets to create new products that bring happiness, play with flavors and designs, and satisfy her scientific curiosity by solving challenges and creating delicious and beautiful products.