When I was in cooking school, I loved showing off my newly acquired culinary skills in front of my sisters. One winter break, my sister Laurie was baking a birthday cake for a friend in my mother's wood-paneled Brooklyn kitchen. Being a typical culinary student, I was appalled to see her reach for a can of ready-made frosting.
"Why don't you just make ganache?" I asked in my best I-know-something-that-you-don't-know tone.
"What's that?" she asked.
Seizing the opportunity to impress my sister with a basic pastry technique, I looked around the kitchen for chocolate and cream. I heated the cream in the microwave and poured it over the chocolate. From those humble ingredients emerged a luxurious, decadent frosting. She was amazed. What sounded exotic and mysterious was so easy that even her sister could do it!
While it does sound exotic, basic ganache is made with just two ingredients: chocolate and cream. By varying techniques and tweaking ingredients, you can turn basic ganache into a truffle, a glaze, a frosting, a mousse, a tart, a warm drink, or a frozen pop.
Adjusting the proportion of chocolate and cream changes the density of the finished product. More cream makes it thinner and lighter and more chocolate makes it thicker and denser. You can also manipulate ganache by changing its temperature. It becomes thinner as it heats and thicker as it cools.
The idea of mixing two ingredients seems simple. But mixing chocolate and cream is equivalent to mixing oil and water, which can't normally be done. This process of mixing two unmixable ingredients is called emulsification.
Remember the school science fair? Wasn't there always a kid with an oil and water display? He'd plop some oil into the water, but instead of dissolving, it would float to the top. What that kid didn't know is that oil and water actually can be mixed, with a little help from heat and agitation.
The emulsification that results in ganache combines the fat in chocolate (cocoa butter) with the water in cream. To accomplish this, you must first liquefy the fat. Hot cream is combined with the chocolate, melting the fat into liquid form. Stirring breaks down the fat into microscopic droplets, small enough to be suspended within the water. Whipping and heavy cream may be used interchangeably to make ganache. They differ in the amount of butterfat they contain. As a general rule, the higher the fat content of the cream, the richer the finished ganache will be.
Temperature is an important factor in the emulsification of ganache. If the temperature is not controlled carefully, the result will not be smooth. The optimal emulsification temperature for ganache is 90 degrees to 110 degrees F. If the temperature rises above 110 degrees F, the cocoa butter gets too hot. Droplets of fat will pool together and rise to the surface, separating from the mixture. When this occurs, the ganache is referred to as "broken."
Ganache can also be lumpy if the chocolate is not chopped into very fine pieces before being combined with the hot cream. If the chocolate pieces are larger than 1/4 inch, they will not melt completely and the resulting ganache will have lumps. Lumpy ganache can be repaired by being reheated. Reheating, however, can easily cause the fat to overheat, pool together, and break the ganache.
After the cream is poured over the chocolate to melt the cocoa butter, the mixture is set aside to warm undisturbed for a minute and then stirred in a slow, circular motion. Steady agitation is essential in reducing the fat to tiny droplets. Care must be taken to resist excessive beating, which can bring the temperature of the fat below 90 degrees F too quickly, producing ganache with a grainy texture.
Repairing a Broken or Grainy Ganache
If your ganache looks broken or feels grainy, there is still hope for it. To repair a broken ganache, divide it in half. Warm one half over a double boiler to a temperature of 130 degrees F. The fat will melt and pool at this temperature, making the mixture thinner. Cool the remaining ganache to 60 degrees F by stirring it over a bowl of ice. The fat in this portion will begin to solidify, causing the ganache to thicken.
When both halves have reached the desired temperatures, slowly stream the hot ganache into the cold and stir to combine. You can use a food processor for this step by placing the cool ganache into the bowl of the food processor, turning on the machine, and streaming in the warm ganache. The mixture will not fall below 90 degrees F during this procedure, so there is no risk of creating a grainy texture. Combining the two portions of ganache in this way averages the temperature into the optimal working range, and the fat droplets will be suspended evenly in the water.
The most common chocolate used for ganache is dark chocolate. Dark refers to the color and includes sweet, semisweet, bittersweet, and unsweetened chocolates. Chocolate is made from cocoa beans that have been roasted and pulverized. The result is chocolate liquor, also known as cocoa mass.
As the beans are ground, they exude cocoa butter. Different amounts of cocoa butter are added back into the mixture, depending on which type of chocolate is being made. Dark chocolate contains less cocoa butter than milk chocolate. White chocolate is comprised of nearly all cocoa butter and no chocolate liquor. (Due to the lack of chocolate liquor, white chocolate is not technically chocolate. However, it can be used in the same manner as types containing chocolate liquor, with certain modifications.)
Chocolates also differ in the amount of sugar they contain. Bittersweet has less sugar than semisweet. Unsweetened chocolate has no added sugar, and I often used it in conjunction with bittersweet for an extra dark, intense flavor.
Milk solids, which contain milk fat, are used to make milk and white chocolate. The added fat and the increased cocoa butter content make the lighter chocolates softer and more susceptible to damage from heat. You can certainly make ganache from milk or white chocolate, using the traditional technique, but you'll have to adjust the proportion of cream downward to compensate for the increased fat content.
The Secrets of Baking
Simple Techniques for Sophisticated Desserts
by Sherry Yard
Houghton Mifflin Company
Hardcover; 416 pages
Illustrations: 2-color with 48 color photographs
Excerpt reprinted by permission.
The Secrets of Baking
This page created January 2004