To make it, water is added to regular sugar to form a syrup, along with an acid such as citric acid or tartaric acid (aka lemon juice and cream of tartar.) The syrup is heated. The heating breaks the sucrose in the sugar down into equal amounts of fructose and glucose, thus, the sugar crystals are smaller. Because the crystals are smaller, they can be used to make smoother candies, sweetened condensed milks, and syrups. Home preservers making jams make invert sugar all the time in their pot without knowing it.
The process also occurs naturally in maple syrup from naturally occurring microbes in the sap from the maple trees. A certain amount of invert sugar in maple syrup is desirable for syrup that is to be made into maple butter: too much may prevent the cream from forming, too little may cause the maple butter to be grainy.
New methods of making it have been developed used an enzyme from yeast cells, which results in a conversion of almost 100%, with few of the impurities left behind by the traditional process.
Invert Sugar is sweeter than plain sucrose, because the fructose (which is sweeter than sucrose), is freed up. In beverages, because it is sweeter, it means that less sweetener can be used, reducing costs.
Invert Sugar also:
- dissolves faster than regular sugar because the crystals are smaller;
- retains moisture better;
- when used in frozen products, because it has a lower freezing point, it can keep them soft and more scoopable;
- retains moisture and so improves shelf life of baked goods.
Invert Sugar can be bought either as total invert sugar (50% fructose, 50% glucose), or as a mixture of half sucrose and half invert sugar (making it 50% sucrose, 25% fructose, 25% glucose.)
It is sold in jars.
A package of invert syrup, unopened, has a shelf-life of 2 years; after opening, store in refrigerator and use up within 1 year. Discard if any mould starts growing.
Invert here is used in the sense of “breaking down”, rather than “turning upside down”. When polarized light is passed through a solution of invert sugar, it rotates the light in the opposite direction that a solution of sucrose would. How inverted the light is, is a way to measure how much of the sugar has in the solution has been “inverted”. The process of making it is referred to as “hydrolization” or “inversion.