From the Chocolate Vault · Case 2
When shrinkage matters
A client with factories in the USA and Thailand held a licence to produce chocolate merchandise for a major film franchise.
Some of the easier chocolate products had already been launched successfully, but the next product in the pipeline required a little more thought.
By good fortune, all the key people involved were attending Interpack in Düsseldorf at the same time: the mould manufacturer, the depositing line supplier, the marketing team, my client and myself.
When I looked at the proposed product design, a few red flags immediately appeared.
Grab points
A well-tempered chocolate naturally shrinks as it cools and sets. Normally, this is good news: that shrinkage helps the chocolate release cleanly from the mould.
The problem comes when the shape of the product prevents that shrinkage from happening freely. I sometimes describe these as grab points.
Think of a moulded Easter bunny. You may have a larger mass of chocolate forming the head and ears, another larger mass forming the body, and a relatively thin section through the neck joining the two together.
As the larger masses shrink, that narrow section becomes the weak point. If the product geometry prevents the chocolate from moving freely during contraction, the stress has to go somewhere. And very often, it finds the weakest section.
The product snaps.
“That’s what you’re here for”
We discussed the issue at Interpack, and the outcome was fairly straightforward:
- The product design could not be changed.
- The client was prepared to accept the risk.
- And, essentially, “That’s what you’re here for. Make it work.”
Fair enough.
So while the moulds were being manufactured, the depositing line was being programmed, and the artwork and packaging were moving through their respective processes, I was quietly looking for a seat on the first mission to Mars.
Production start in Thailand
Eventually, the production start date arrived and I headed to Thailand.
My plan was simple. Start with a baseline using normal chocolate moulding conditions, see exactly what happened, and then begin moving the process variables based on the results.
The first trial confirmed the concern. Perfect temper. Good moulding conditions. Good cooling. And approximately 90% broken product.
So now it was time to find a few rabbits, or perhaps bunnies, in the hat.
The key was shrinkage. We needed enough contraction for the chocolate to release from the mould, but not so much that all of the shrinkage occurred while the product was still being restrained by its geometry.
The process therefore had to be changed so that the product released from the mould at the right point, allowing the remaining contraction to occur after demoulding, free from those stress points.
It took a series of relatively small changes across the moulding and cooling process. Rather than trying to force the chocolate to behave according to conventional settings, we changed the process to suit the behaviour the product actually needed.
- From around 90% breakage to approximately 98% good product.
- No compromise to the appearance or quality of the finished chocolate.
The lesson
Chocolate processing is not always about achieving the textbook definition of perfect temper, perfect cooling or perfect moulding conditions. Sometimes those conditions are exactly what create the problem.
The product design, chocolate formulation, mould, cooling profile and demoulding point all interact. Understanding how chocolate crystallises and contracts allows those variables to be manipulated rather than simply accepted.
Sometimes the answer is not to make the chocolate behave perfectly. It is to make it behave in the way the product needs.
Mark Tubman, ChocCreator
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