Invert sugar is mostly reserved for the professional pastry chefs and bakers and is generally used in combination with sugar (sucrose). It has a lot of benefits and can be purchased at pastry supply stores or made at home with relative ease.
What is invert sugar?
Invert sugar (also referred to as inverted sugar or inverted sugar syrup) is a mixture of two simple sugars - glucose and fructose. Invert sugar is sweeter than white sugar, having a sweetening power of 125% compared to sucrose (ordinary white sugar). Bakers often refer to invert sugar as trimoline, which is the brand name used by one of its manufacturers.
What are the benefits of invert sugar?
Invert sugar is frequently used when making fudge, creams, ganaches, candies, fondant, cakes, and other products in conjunction with glucose syrup, to control crystallization and help create the small sugar crystals that result in a smooth texture. It's best suited for products with a high water content that must be kept soft.
Invert sugar inhibits crystallization in creams and provides aroma and color when heated.
It also contributes to potential Maillard browning, resulting in a more visually appealing and more flavorful product.
Fructose in invert sugar enhances favor, especially in fruity preparations such as sorbet or jam.
Invert sugar acts as a humectant, helping to retain moisture in the finished product and prevent it from drying out. This property is also referred to as increased hygroscopicity. For this reason, some bakers use it more than other sweeteners.
Invert sugar also has preservative effects due to its high degree of solubility, which lowers the water activity level, resulting in longer shelf life for the finished product.
Adverse effects of invert sugar
When used in excess, invert sugar gives fudge and other confections an excessively soft, pliable texture, which is undesirable. Another adverse effect may be an overly sweet confection.
Finally, baked goods prepared using invert syrup brown at a lower temperature and require shorter baking times than those made with sucrose.
For the reasons mentioned above, invert sugar is used only as an accompaniment to sucrose.
How is invert sugar made?
Invert sugar is made by splitting disaccharide sucrose into its two component monosaccharides, fructose (also known as levulose) and dextrose (also known as glucose).
The conventional way to make invert sugar is by the hydrolysis of sucrose to glucose (dextrose) and fructose. This is achieved by subjecting a sucrose solution to acid and heat. However, acid hydrolysis has a low conversion efficiency and high-energy consumption.
This conversion can also be achieved by the enzymatic action of invertase (immobilized yeast cells) on sucrose with a conversion efficiency of almost 100% without the inherent disadvantages of acid hydrolysis. You can read more about the production of invert sugar in the Invert Sugar Production Line. This is how commercial producers make invert sugar today.
Best way to make invert sugar at home
At home, the best way to make invert sugar is by heating white sugar, water, and citric acid or cream of tartar.
Chef Eddy provides the most commonly used recipe for invert sugar. I've successfully made invert sugar using this recipe many times and this is my 'go-to' recipe.
To make 1 kilo of invert sugar, his recipe calls for 1 kg (4 cups + 6 Tbsp) extra fine granulated sugar, 480 g (2 cups) water and 1 g (1/4 tsp) cream of tartar or citric acid.
You will need a good candy thermometer, a pastry brush, and a thick-bottomed stockpot.
The ingredients are stirred and brought to a boil in a non-reactive saucepan over medium-high heat. Once the mixture is boiling, reduce the temperature to medium and continue boiling without stirring. Stirring will cause crystallization, which is undesirable.
Any sugar crystals formed on the walls of the saucepan are washed with a pastry brush dipped in water, without the brush ever touching the mixture. You want the water to gently roll down into the mixture. This water will not cause any adverse effects.
The mixture is boiled to 236F (114C), after which it is removed from heat, covered and cooled down to room temperature, undisturbed. Homemade invert sugar will store in a fridge for at least six months.
Another recipe, slightly more complicated, was provided by Jean-Pierre Wybauw in his Fine Chocolates 2: Great Ganache Experience book. You can find this recipe re-published and discussed on eG Forums.
Where to buy invert sugar?
Invert sugar is made commercially and is available online as Inverted Sugar Syrup or Liquid Invert Sugar. You can find it under the brand name of Trimoline. You can buy it in bulk from The Pastry Chef or The Pastry Depot.
Invert sugar substitutes
In a pinch, you may substitute liquid honey, corn syrup, or maple syrup for invert sugar. All three contain some amount of invert sugar. Keep in mind though, these products will impart their flavor, and the results will be a bit different.
Sources:
The Art of the Chocolatier: From Classic Confections to Sensational Showpieces
Chocolates and Confections: Formula, Theory, and Technique for the Artisan Confectioner
Kaye Blewett
I have made the Chef Eddy recipe three times but sadly after a couple of weeks it crystalises and becomes solid and unusable. Not sure what I am doing wrong?
Victor @ Taste of Artisan
Something must be off as mine doesn't begin to visibly crystallize for months, which I am quite happy about as I don't use it much or too often; I keep it in a cool, dark place. It's hard to say what caused crystallization in your case but here is a very informative discussion - https://cooking.stackexchange.com/questions/76048/why-does-my-invert-sugar-always-crystallize - about the same problem with possible solutions to try. Good luck!