If molten chocolate was a superhero, then water would be kryptonite.
Introducing any amount of water to molten chocolate will trigger a cascade of disastrous events that can transform a beautiful, glossy pan of molten chocolate into a gritty, unworkable and unappealing mess.
Dramatic water drops
The most dramatic consequence of water contamination is “seizing”. This phenomenon transforms smooth, liquid chocolate into an unworkable gritty messy lump in a matter of seconds.
See our video for a demonstration of water on chocolate: the nemesis of chocolate-makers.
This process is often irreversible. Even experienced professional chocolatiers will have a hard time trying to rescue chocolate that has seized.
When water is introduced, the sugar crystals, which were previously suspended in the cocoa butter, rapidly dissolve and recrystallize around the water molecules. This pulls the cocoa butter out of its suspended emulsion state, causing the fat particles to clump together and the overall texture to degrade rapidly.
Once seized, chocolate is very difficult to rescue. While some chefs attempt to salvage it by adding a warm liquid fat (like vegetable oil or melted butter) or warm dairy cream, these additions dilute the chocolate and will not restore the shiny, glossy texture of the original product.
Hack: add warm molten cocoa butter or heavy cream, one teaspoon at a time, to fix the damaged chocolate. Stir the product with a wire whisk, while you add the liquid in a very thin stream.
The rescued chocolate is usually relegated to a secondary role; ganache, chocolate pastries or hot cocoa drinks. Sometimes seized chocolate cannot be saved at all and it ends up in the garbage bin.
The delicate aromatic compounds in chocolate are sensitive to moisture, and water contamination can lead to an off-flavor, or can lead to rancidity and a stale taste. From a shelf-life perspective, water is a breeding ground for microorganisms, significantly increasing the risk of spoilage.
The importance of kitchen hygiene
Kitchen hygiene is an absolute necessity when working with molten chocolate.
Remember: every piece of equipment that comes into contact with chocolate – bowls, spatulas, spoons, double boilers, molds, whisks – must be absolutely dry.
Never use water-based flavours or colours directly with chocolate: this includes vanilla, alcohol and all fruit juices and jams. There are workarounds for these water-based ingredients that use gels compatible with chocolate.
Always use oil-based colours and flavours. Unless your flavour is an essential oil (chili, mint, orange), the flavour must be infused into a “warm carrier” like butter or dairy cream or cocoa butter; before adding it to chocolate. The same principle applies to colours: oil-based liquids can be used directly, powdered colors have to be dissolved in a “warm carrier”.
Steam, a byproduct of using a double boiler or even ambient humidity, can be the source of water contamination.
Using a lid on a double boiler can cause condensation to drip back into the chocolate. Therefore, it’s crucial to use a double boiler where the upper bowl does not directly touch the water below, and to ensure adequate ventilation to prevent steam from condensing on surfaces that might then come into contact with the chocolate.
Even a single drop of residual water from washing can seize your chocolate
Hands, too, are a common source of moisture. Even seemingly dry hands can carry enough residual moisture from washing or perspiration to cause problems.
Using clean, dry gloves, or ensuring hands are completely dry before handling chocolate, is critical.
Similarly, ingredients added to chocolate, such as nuts or dried fruit, must be completely dry. Any moisture on their surface will instantly cause problems.
The science of water and oil
The reason for water’s devastating effect lies in the immiscibility of water and oil, in this case, the cocoa butter in chocolate.
Water is a polar molecule, meaning it has a slight positive charge on one end and a slight negative charge on the other. This allows water molecules to form strong hydrogen bonds with each other. Oils, on the other hand, are non-polar molecules. They lack the charged regions necessary to form hydrogen bonds with water.
Polar substances dissolve in other polar substances, and non-polar substances dissolve in other non-polar substances. Water and oil, being polar and non-polar respectively, simply do not mix. Instead, when forced together, they form two distinct layers, with the less dense oil typically floating on top of the water.
In molten chocolate, the cocoa butter forms the continuous phase, suspending the solid particles of cocoa solids and sugar. When water is introduced, it disrupts this delicate balance. The water molecules, attracted to the hydrophilic sugar, pull the sugar out of its suspension in the fat, causing it to cluster around the water. This, in turn, forces the cocoa butter to separate and clump together, leading to the seized chocolate.
While the home chocolatier must exercise extreme caution, the food industry routinely produces chocolate products that contain water, such as chocolate milk or certain chocolate fillings.
How do they achieve this without seizing? The answer lies in the use of emulsifiers; molecules that have both a hydrophilic (water-loving) and a lipophilic (oil-loving) part. This unique structure allows them to act as bridges between water and oil, enabling them to form stable emulsions.
Lecithin, particularly soy lecithin or sunflower lecithin, is the most common emulsifier used in chocolate. Lecithin is naturally present in egg yolks and soybeans.
In chocolate, lecithin works by reducing the surface tension between the cocoa butter and any trace amounts of water that might be present. It encapsulates the water droplets, effectively preventing them from interacting with the sugar and causing seizing. This allows for a smooth, homogenous product even with the presence of some moisture.
Conclusion
Adding water to molten chocolate unleashes a chain of events that can ruin the product.
Understanding the science behind the immiscibility of water and oil, and the crucial role of kitchen hygiene in preventing contamination, is paramount for quality chocolate-making at home.