What is corn syrup?
Corn syrup is a sweet, edible syrup made from the naturally occurring sugars found in corn. It is generally used as a sweetener, and can be purchased in bottles to use in cooking, or added to processed foods on an industrial scale.
There are two types of corn syrup available to buy in the shops; light corn syrup and dark corn syrup. Light corn syrup is a clear syrup, often flavoured with vanilla, while dark corn syrup is flavoured with molasses, creating a richer, sweeter taste with caramel notes. Many processed foods contain a different type of corn syrup, known as high-fructose corn syrup, which is much sweeter than regular corn syrup.
Corn syrup is sometimes referred to as glucose syrup, particularly in the USA, where most glucose syrup is made using corn. This is a generic term, however, and can also be used to describe syrups made from other sources of starch, such as wheat, tapioca or potatoes.
How is it made?
Corn syrup is made by breaking down the starches found in corn into a type of sugar called glucose. Starch is a more complex type of carbohydrate, made of long chains of molecules, while sugars are made of shorter chains. Breaking the bonds that hold the starches together will convert them into shorter chains of sugar, and one way to do this is using enzymes, just like our bodies use them to break down the food we eat.
First, cornstarch is extracted from the starchiest part of the corn kernels, known as the endosperm, and mixed with water. Next, two different types of enzymes are added. The first breaks the starches into shorter chains of glucose molecules, while the second breaks the chains of glucose down into individual glucose molecules. These glucose molecules create a sweet syrup that is essentially corn syrup in its basic form. At this point, flavourings such as vanilla and salt, for light corn syrup, or molasses, for dark corn syrup, can be added.
To make high fructose corn syrup, a further enzyme is added, which converts some of the glucose molecules into fructose, another type of sugar with a much sweeter flavour.
How to use it
Corn syrup is used as a sweetener, particularly when a recipe calls for a smooth texture. It is sometimes referred to as an ‘invert sugar’, because unlike table sugar and even some other syrups, it won’t form large, grainy crystals when left to cool. This makes it popular when making fudge, candies, shiny frostings, glazes and dessert sauces, or jams and jellies. It is also used alongside sugar to give a creamier texture to frozen desserts like ice creams and sorbets.
A 1 tablespoon serving of corn syrup contains the following
Of which sugars: 17g
As might be expected, corn syrup is composed almost entirely of sugars, with as little as a tablespoon providing 6% of your recommended daily value for carbohydrate. It is also very high in calories, and because salt is often added as a flavouring, it is quite high in sodium too, with the same 1 tablespoon serving providing 1% of your daily value.
Is corn syrup good for you?
Again, perhaps unsurprisingly, corn syrup is not particularly good for your health, but just how bad it is for you depends on the type of corn syrup. You may have heard bad things about corn syrup, but much of the negative press specifically refers to high fructose corn syrup, the kind used in processed food.
High fructose corn syrup, or HFCS, has been the cause of much concern due to its high fructose content. Unlike other sugars, fructose can only be processed by the liver, and eating too much can cause your liver to turn the sugar into fats. These fats are a key contributor to several serious health problems including diabetes, obesity, a fatty liver and memory loss. Fructose is also thought to increase feelings of hunger and sugar cravings, which increases the risk of obesity.
Health problems caused by fructose are often associated with HFCS, but the most commonly-used forms of HFCS contain between 42 to 55% fructose, which is a similar amount to other popular sweeteners, including table sugar and honey. Of course, this doesn’t mean HFCS gets a free pass - it’s still pretty bad for you - but in terms of fructose content it doesn’t appear to be significantly worse than other types of sweetener. There are forms of HFCS that contain 90% fructose, and these are thought to be particularly bad for your health, but they tend to be less commonly used.
The type of corn syrup you buy from the shops to use in baking is largely made of glucose, which is generally considered to carry a lower health risk than fructose. In this sense, regular corn syrup can be considered less dangerous than regular table sugar, but it is important to remember that all sugars carry an increased risk of obesity, heart disease and other health problems, and should be enjoyed in moderation only.
Corn syrup may be relatively unhealthy, but how about the vegetable it comes from? Find out all about the advantages and disadvantages of eating corn in our article: Is Corn Good For You?
How to substitute corn syrup
If your recipe calls for corn syrup and you’re all out, here are a few alternatives you can use in a pinch.
Has a similarly neutral taste, so it won’t alter the overall flavor of your dish, and it also has a similar consistency to corn syrup. It doesn’t prevent the formation of sugar crystals, however, so it doesn’t work so well for candy making, and if you’re concerned about the health implications of high fructose sweeteners, it’s worth noting that agave is one of the worst offenders, with a fructose content of up to 90%.
Brown rice syrup
Has a similar consistency to corn syrup, and will prevent crystallisation, making it a good option for candy making. It has a slightly nutty flavour, similar to brown rice, that may not complement every recipe.
Is a popular baking ingredient in Britain, and has a light, mellow flavour. It has a similar consistency to corn syrup and can be used to prevent crystallisation in candy making.
Is also of a similar consistency to corn syrup, but cannot be used to prevent crystallisation. It does have a strong flavour, so try to use a milder variety like acacia or clover honey.
Has a similar consistency to corn syrup, but it doesn’t prevent sugar crystallisation, so it’s not a great option for candy making.