Granular detail: invert sugar

Invert sugar is widely used in food and beverage manufacturing, thanks to its ability to hold water and its potent sweetness, giving a range of textures and tastes to products. As invert syrup manufacturers, Ragus produces both types of invert sugar syrups: fully inverted sugar syrup and partially inverted sugar syrup. Read on to find out what they are, and why they’re so perennially popular in baked goods, confectionery, frozen treats and drinks. 

Invert sugar typically starts life as sucrose, otherwise known as white table sugar. It’s called ‘inverted’ sugar because when the transformation process is over, light shines through inverted sugar in the opposite direction to that of sucrose. 

It also has different functions and applications to regular table sugar. As a disaccharide, sucrose contains two molecules – one of fructose and one of glucose – bound together. The invert sugar syrup manufacturing process breaks down those bonds to create a sugar that contains only monosaccharide, or single sugar molecules: free, separated fructose and glucose molecules. 

It is when the chemical structure of fructose uniquely interacts with water that human taste buds perceive the sugar to be intensely sweet, much more so than sucrose.  There are two types of invert sugar syrup that are differentiated by the ratio of sucrose to the inverted sugars glucose and fructose.

There’s partially inverted sugar syrup, such as golden syrup, where about half of the sucrose is broken down into inverted sugars, and fully inverted sugar syrup, where nearly all of the sucrose is inverted into glucose and fructose.

As a result of the sucrose to inverts ratio, both the sugar syrup manufacturing process and applications differ. 

To manufacture fully inverted sugar syrup, water is heated in large-scale inversion pans to 70 degrees centigrade. Sucrose is added to create a sugar saturation, at which point an acid is added to bring the pH down to 1.6. These three elements, sugar saturation at a temperature of 70 degrees centigrade and at a pH of 1.7, results in the sucrose breaking down, or inverting, into fructose and glucose. 

For a fully inverted sugar syrup, the reaction is allowed to continue until the brix is 76%, and the polarisation is -18 to -22 at which point a natural alkaline agent is added that brings to pH to between 5 and 6. Colourless full inverts are cooled and packed as soon as possible, to avoid caramelisation that turns syrups a darker, yellower hue. 

Partial inverts, such as golden syrup, are manufactured using a slightly different process. With full inverts, all the sucrose is added at the start, but to produce a partial inverted sugar syrup, the sucrose is added in two stages. The initial stages are the same, heating the water to 70 degrees centigrade and adding the sucrose, and reducing the pH to between 1 and 1.6. The difference is that less sucrose is added initially, the remainder being added after inversion. 

Once all the sugar crystals are dissolved and the temperature is over 70 degrees, the sucrose will invert into glucose and fructose. After the desired ratio of sucrose to fructose is achieved alongside a polarisation of -14, the syrup is neutralised with a natural alkaline agent. 

To add colour to the partial invert, for darker syrups such as golden syrup, the mixture is caramelised in the inversion pans using heat and time, which are varied according to the desired flavour and colour profiles. Then after the remaining sugar is added and dissolved, for golden syrup the brix will be a maximum of 83%, and the polarisation +20. 

To bind and remove the non-sugar particles in the syrup an alkaline powder is added. Here at Ragus, when we use white sugar for our inverts, there are no raw sugar fibres present, so we just pass them through an 80-micron filter for the final stage of the process. 

For standard golden syrups, because we use raw sugar as a base, we need to sift out the gums, fibres and waxes before using the 80-micron filter, so we pass it through a plate and frame filter press too. Then it is packed and transported it to our customers.  

Despite being a famous pure sugar in its own right, golden syrup is actually a special type of partially inverted sugar syrup. Better known as an independent sugar product than for being a partial invert, up until the final stages of the manufacturing process, golden syrup doesn’t differ from a ‘regular’ partial invert. 

It’s only through the heating and ageing process, when further caramelisation occurs and when straight sucrose is added near the end, making it a mix of inverted sugar and sucrose, that it becomes the iconic product we know and love that was first formulated in 1883 by Ragus’ founder, Charles Eastick. 

Invert sugar is used in a diverse range of food and beverages, including ice cream, sorbets, fondants, soft drinks, baked goods and cough syrups. As well as bringing flavour, invert sugar serves important functions in these products. For example, its ability to retain moisture leads to a longer shelf life for baked goods. It also depresses the freezing point of ice creams and sorbets, making them easier to scoop. 

Invert sugar’s moisture retaining abilities makes products more resistant to microbial spoilage, extending shelf life and keeping them fresher for longer. And, because it reduces sugar crystallisation, it gives products a smoother, softer texture. For soft drinks, its ability to easily dissolve in cold liquids makes it better than sucrose as a sweetener. 

At Ragus, we supply full invert syrup and partial invert syrup. Full invert syrup is a mixture of nearly all invert sugar to sucrose, resulting in a sweetness value 40% greater than sucrose. Partial invert syrup, such as Eastick’s golden syrup, is a combination of around half sucrose with half invert sugar, making it 20% sweeter than straight sucrose. 

What advice do Ragus Pure Sugars give clients when buying invert sugar? 

As an experienced, industry-leading invert syrup manufacturer, we know how to give our customers exactly what they need for their food and beverage products. We usually ask a few crucial questions, starting with how much invert sugar you’ll use per month.

We also need to know which type of packaging containing the invert sugar you need. The options are usually intermediate bulk containers (IBCs) and bulk tankers. Also, what are the ambient conditions of your storage location? 

When we know your answers, we can supply you with the right type and amount of invert sugar syrup.  

Full inverts behave in the same way as honey, meaning they can begin to crystallise in cold temperatures after four months of storage, with a shelf life of around six months. Partial inverts, such as like golden syrup, have a shelf life of 6 months crystallisation and 12 months microbiology. Any invert sugar going into storage – particularly full inverts in bulk tanks – must go into trace heated tanks to stop crystals forming.  

Ragus supplies high-quality full and partial invert sugar syrups to our industrial food and beverage and pharmaceutical customers maximise taste, texture, appearance and shelf-life. Contact our Customer Services Team to learn more about our pure sugars. For sugar industry news and Ragus updates, keep browsing SUGARTALK and follow Ragus on LinkedIn.