How is Liquid Glucose Made? The Step-by-Step Guide

December 29, 2025 •

3 min read

Over 90% of industrially produced liquid glucose is used in fermented products, highlighting its importance in food and beverage manufacturing. This syrupy liquid is a cornerstone ingredient in many products, and understanding how is liquid glucose made reveals a sophisticated process of converting complex starches into simple sugars.

Quick Summary

The creation of liquid glucose involves a multi-stage industrial process that begins with starch extraction from sources like corn or rice. It proceeds through controlled enzymatic or acid hydrolysis, followed by several refining steps, including decolorization and ion exchange, culminating in evaporation to achieve the desired concentration.

Key Points

Source Materials: Liquid glucose is made by hydrolyzing starch, primarily sourced from crops like corn, wheat, or rice.
Starch Extraction: The initial step involves separating and purifying the raw starch from other components like protein and fiber contained in the plant source.
Enzymatic Hydrolysis: The modern, precise method uses enzymes, first alpha-amylase to liquefy starch into dextrins, then glucoamylase to convert dextrins into glucose.
Acid Hydrolysis: An older, simpler method uses dilute acid and heat, though it can result in lower quality and a darker colored syrup.
Purification: The resulting crude sugar solution is filtered, decolorized with activated carbon, and passed through ion exchange columns to remove impurities and inorganic salts.
Concentration: The purified liquid is evaporated under vacuum to remove excess water and concentrate the syrup to its final viscosity and solids content.
High Quality Standards: Industrial production is controlled by rigorous standards to ensure quality, including monitoring dextrose equivalent (DE) and purity levels.

From Starch to Syrup: Understanding the Raw Materials

Liquid glucose, also known as glucose syrup, begins its journey as a complex polysaccharide found in various plant-based starches. The primary sources for commercial production are typically corn, potatoes, wheat, or rice. The specific source can influence the final properties of the syrup, such as taste and viscosity.

Starch Preparation and Extraction

The process starts by preparing the raw starch slurry. The raw material, such as corn kernels, is first cleaned and milled to separate the starch from other components like protein, fiber, and germ. This step is critical for ensuring the purity of the final product and is typically done using methods like steeping, crushing, and centrifugation.

The Hydrolysis Process: Breaking Down Starch

Once the pure starch slurry is obtained, it undergoes hydrolysis, the core chemical process that creates liquid glucose. This can be achieved through one of two primary methods, each yielding different results in terms of sugar profile and quality.

Enzymatic Hydrolysis

This is the most modern and widely used method for high-quality syrup production, offering greater control over the final product's properties. It involves a two-stage enzymatic reaction:

Liquefaction: The starch slurry is heated and treated with an alpha-amylase enzyme. This enzyme breaks the long-chain starch molecules (polysaccharides) into shorter, simpler carbohydrate chains called dextrins or oligosaccharides.
Saccharification: The resulting liquid is then treated with another enzyme, glucoamylase, which breaks down the dextrins into individual glucose molecules. The duration and conditions of this step determine the dextrose equivalent (DE) of the final syrup, a measure of its sweetness.

Acid Hydrolysis

An older, less controlled method, acid hydrolysis involves mixing the starch slurry with a dilute acid, typically hydrochloric acid, and heating it under pressure. While cost-effective, this method can produce unwanted byproducts that may lead to a darker color and a slightly bitter taste in the finished syrup.

Refining and Purification Steps

After hydrolysis, the resulting liquid is still a crude, impure solution that requires extensive refining to become the clear, stable syrup we know. This purification process typically includes several steps:

Filtration: A filter press is used to remove insoluble solids, such as residual protein and fiber, from the crude glucose liquid.
Decolorization: The syrup is treated with activated carbon, which absorbs colored organic impurities. This process improves the syrup's visual quality and prevents degradation.
Ion Exchange: The liquid is passed through ion exchange columns containing specialized resins to remove inorganic salts and other charged impurities. This step is crucial for achieving a high level of purity.

Concentration: Evaporation into a Syrup

With all impurities removed, the final step is to concentrate the solution by evaporating excess water under a vacuum. This evaporation process, often carried out using multi-effect evaporators, increases the syrup's solids concentration to the desired level, typically 80–85% solids for commercial use. A vacuum is used to keep the temperature low, which prevents the syrup from darkening or developing off-flavors from heat exposure.

Industrial vs. Home-made Liquid Glucose Production


Feature	Industrial Production	Home-made Recipe (Example)
Raw Material	Corn, wheat, potato, or rice starch	Table sugar (sucrose)
Hydrolysis Method	Controlled enzymatic or acid hydrolysis	Inversion using acid (lemon juice or cream of tartar) and heat
Equipment	Industrial mixers, jet cookers, filter presses, evaporators	Saucepan, measuring cups, stove
Refinement	Multi-stage filtration, decolorization, ion exchange	Simple process, often with no refinement or limited straining
Purity & Consistency	Highly controlled with specific DE values and low impurities	Variable purity and consistency, prone to crystallization
Scale	Large-scale, high-volume manufacturing	Small-batch for domestic use

Conclusion: From Starch to a Sweet, Versatile Ingredient

The manufacturing process for liquid glucose is a highly refined and technically advanced procedure that transforms raw, plant-based starches into a stable, pure, and versatile syrup. From the careful extraction of starch to the controlled hydrolysis and meticulous purification, each step ensures a consistent product that is indispensable across a wide range of industries, from confectionery to pharmaceuticals. The modern enzymatic method offers superior control and quality, replacing older, less precise acid-based techniques. This journey from a complex carbohydrate to a simple sugar demonstrates a sophisticated blend of chemistry and engineering that underpins many of the products we use daily. To delve deeper into the complex world of industrial food production and starch processing, you can consult technical resources like the Corn Refiners Association.

Frequently Asked Questions

Liquid glucose is typically made from starches extracted from plant sources such as corn, wheat, potatoes, or rice. The specific source material can vary by region and manufacturer.

Starch hydrolysis is the chemical process of breaking down long-chain starch molecules (polysaccharides) into smaller sugar molecules, like glucose, through the addition of water. This is achieved using either enzymes or acid.

Enzymatic hydrolysis uses specific enzymes for a more controlled breakdown, resulting in a higher quality, lighter-colored syrup. Acid hydrolysis uses dilute acid and heat, which is less controllable and can produce unwanted byproducts and a darker color.

Purification is essential to remove impurities like residual protein, fiber, and inorganic salts. Steps like filtration, decolorization, and ion exchange ensure the final syrup is clear, stable, and meets food-grade standards.

The Dextrose Equivalent (DE) is a measure of the total amount of reducing sugars, primarily dextrose, present in the syrup relative to the starch. It indicates the degree of hydrolysis and directly relates to the syrup's sweetness.

After the purification process, the dilute glucose solution is concentrated to the desired solids content by evaporating excess water. This is typically done under vacuum to protect the syrup's quality from high temperatures.

No, they are different. While both are made from corn starch, liquid glucose (or corn syrup) contains a mixture of glucose, maltose, and other sugars. High fructose corn syrup is further processed using an additional enzyme to convert some of the glucose into fructose, making it sweeter.