What’s the difference between partial and full invert sugar syrup?

Invert sugars are some of the most widely used ingredients in industrial food and beverage production because they serve vital functional purposes as well as acting as sweetness enhancers. This blog explains the differences between the two main types, partial and full invert sugar syrup, and details how the attributes of each benefit their respective applications.

Invert sugar is, of course, sugar that has been inverted. But what does this mean? Well, regarding the sugar product that you find on the back of a label, it is straight sucrose – white table sugar – that has been transformed into a sweeter and more beneficial sugar product. Once this process has taken place, light shines through invert sugar in the opposite direction to when shone through straight sucrose and, therefore, it is ‘inverted’.

For sugar manufacturers, invert sugar is produced by breaking down glucose and fructose molecules that are bonded together in straight sucrose. Indeed, this disaccharide bond is broken down so that the glucose and fructose molecules are free, with this inversion process subtly altered to produce partial and full invert sugar syrup. You can find out more information about the nuances between the two production processes here.

It is worth noting that invert sugars also occur naturally. Both honey and the sap of a daffodil are naturally occurring invert sugars, for example. However, in terms of the sugar products made from natural sugars, partial and full invert sugar syrups are typically produced at scale because the processes involved require extensive sugar expertise and world-class manufacturing equipment to deliver consistent and quality results.

With this in mind, then, what exactly is the difference between partial and full invert sugar syrup?

Partial invert, also labelled by some as medium invert, retains more sucrose from its production process, simply because it is only partially inverted. Indeed, a partial invert is typically a combination of 32.5-35.5% sucrose to 42.5-45.5% invert, but it is important to remember that this ratio varies depending on the partial invert being produced.

With more sucrose retained in the syrup, partial invert tends to have a yellow appearance. And as nearly half of the sucrose has been inverted, partial invert is approximately 20% sweeter than straight sucrose, however, this represents a key distinction between partial and fully inverted sugar syrup: partial invert is much sweeter than straight sucrose but typically only half as sweet as a full invert.

Partial invert also has a much lower water content than straight sucrose. As a result, this increases its preservative qualities, reducing crystallisation and enabling it to withstand higher temperatures during manufacture.

A full invert retains less sucrose from its production process because it has been fully inverted. This means the majority of the sucrose has been converted into separate fructose and glucose molecules. A typical analysis shows that full invert is a mixture of 3.5-5.5% sucrose to 71-77% invert, however, the ratio varies depending on the full invert being produced.

As a result of less sucrose being retained in the syrup, full invert usually has a clearer appearance than partial invert. For this same reason, full invert has a sweetness value approximately 40% higher than straight sucrose and 20% higher than partial invert.

Both partial and full invert sugar applications are integral to the development of a far superior end product, but they are often used in different ways.

Both types of invert syrup are used as humectants because they retain the moisture and prevent microbial spoilage, however, there is an important difference between the two inverts. Partial inverts have a longer shelf life than full inverts and are more often primarily used for this quality.

In terms of specific applications, partial invert sugar syrup is a highly popular ingredient for soft drinks manufacturers because its high sweetness value results in a better flavour than artificial sweeteners while also enabling a 20% reduction in sucrose used. Furthermore, partial invert also lends itself to the production of cereal bars, mixes, cakes and flapjacks, enhancing the flavour and extending the shelf life of all.

Partial invert sugar syrup is often the sugar constituent of choice in soft drinks production. 

On the other side of the spectrum, full invert is often used in icings and fondants due to its higher sweetness value. In such applications, it also prevents crystallisation and keeps the products soft and smooth. Similarly, it is used as a replacement for glycerine in low-fat baking products and to prevent crystallisation in confectionery production.

Full invert is also notably used as a sweetener and bulking agent in ice creams, frozen desserts and sorbets. In ice cream applications, for example, full invert plays a crucial functional role by depressing the freezing point of the product and ensuring a soft and scoopable texture.

Full invert sugar syrup enhances ice cream scoopability. 

While we have established that partial invert and full invert sugar syrup have different properties and uses, the distinction between the two is uniquely complex. This is largely because the formulations of both types of invert can be altered to meet the requirements of a specific end product or production process. Indeed, this capability is what makes invert sugar syrup such a versatile and popular sugar product.

But to make matters more complicated, some of these variations of partial invert sugar syrup are widely recognised sugar products in their own right. Golden syrup and refiners syrup, for instance, are both examples of partially inverted sugar syrups that are better known for being independent sugar products than for being partial inverts.

Not only that, though, there is also confusion over whether invert sugar syrup and high-fructose syrup are the same product, particularly in North America. Crucially, they are not. While both contain glucose and fructose and have similar taste, they are principally distinguished by their raw materials and production processes. Invert sugar is made from natural sugar via an inversion process, whereas high-fructose syrup is a man-made product manufactured from either corn or wheat. These differences result in distinct properties and qualities.

With all these nuances between types of invert sugar and even comparisons to other food syrups, it is easy to get lost in the complexity of it all. Our message to you – don’t try this at home.

Manufacturing at our industry-leading production facility. 

Ragus has over 90 years’ experience manufacturing partial and full invert sugar syrup for industry, having been founded in 1928 with the chief purpose of producing specialist sugars. To learn more about our products, please contact our Customer Services Team. To see more sugar news and updates, continue browsing SUGARTALK and follow Ragus on LinkedIn.