In gummy manufacturing, the ratio of glucose syrup to sucrose is one of the most critical factors determining a gummy's stability and resistance to cold flow, the slow, progressive flattening or spreading of the gummy over time at room temperature. While there is no single "magic number" applicable to all formulations, we at KorNutra have identified a general guideline based on extensive production experience: a gummy becomes prone to cold flow when the glucose syrup-to-sucrose ratio exceeds approximately 70:30 (glucose syrup to sucrose by dry weight).
Understanding the Critical Sugar Ratio
The critical ratio depends on total solids content, the type of glucose syrup (DE value), and the presence of other ingredients like pectin or gelatin. A classic benchmark comes from the sugar glass transition:
- High glucose syrup (above ~70%): Produces gummies with lower glass transition temperatures (Tg). This means the gummy has a softer, more hygroscopic texture, absorbing moisture from the air and leading to cold flow. The gummy may feel tacky or sticky and flattens over days to weeks.
- High sucrose (above ~30%): Raises the glass transition temperature, creating a firmer, less hygroscopic structure that resists moisture uptake and deformation.
For gummy bear-type confections (typically gelatin-based), cold flow becomes noticeable around 65-70% glucose syrup to 30-35% sucrose, and the product becomes high risk when glucose syrup exceeds 70% of the sugar blend, especially in humid environments or with low total solids (under 80% Brix).
Factors That Shift the Critical Ratio
Several parameters can raise or lower this threshold:
- Dextrose Equivalent (DE) of glucose syrup: Higher DE syrups (e.g., 42 DE vs. 62 DE) contain more simple sugars, which lower Tg and increase cold flow risk at lower glucose syrup percentages. Using a lower DE syrup (e.g., 28-36 DE) can allow a slightly higher glucose syrup ratio without flow issues.
- Total solids (Brix): Higher solids (above 82% Brix) increase Tg and reduce cold flow. At lower solids (e.g., 75% Brix), the critical glucose syrup ratio may drop to 60% or less.
- Gelling agent type and concentration: Pectin-based gummies have a different optimal ratio, typically 60:40 or lower glucose syrup, because pectin requires more sucrose for gel formation. Gelatin gummies can often tolerate up to 70% glucose syrup, but only with strong gelatin bloom strength (250+).
Sucrose Inversion During Cooking Changes the Effective Ratio
The finished gummy rarely matches the ratio on the formula sheet. When sucrose is cooked with acid at high temperature, the acid hydrolyzes it into its two component sugars, glucose and fructose. That mixture is invert sugar. It is more hygroscopic than sucrose, so it absorbs moisture and softens the gummy the way a higher-glucose formulation would. Most gummy formulas add citric acid for tartness or to set high-methoxyl pectin. Some inversion is hard to avoid, but it can be limited. Adding the acid late in the cook, keeping cook time and temperature down, or switching to a buffered acid all reduce how much sucrose inverts. The reliable check is to measure the finished product's sugar profile and Tg instead of trusting the formula ratio. A batch that starts at 70:30 can finish with far more monosaccharide than intended if the cook ran long, hot, and acidic.
Practical Manufacturing Recommendations
Based on KorNutra's production standards, we recommend the following to avoid cold flow:
- For standard gelatin gummies, maintain a glucose syrup-to-sucrose ratio of 65:35 to 70:30 as an absolute maximum. Aim for 60:40 for added margin of safety.
- Use a glucose syrup with a DE no higher than 42 for maximum stability. A 33-36 DE syrup is ideal for reducing cold flow risk.
- Keep total solids above 80% Brix. Drying gummies to 82-84% solids improves shape retention.
- Test your gummy at 25°C (77°F) and 60% relative humidity for 48 hours. If the gummy flattens by more than 15% of its original height, reduce glucose syrup or increase sucrose.
Important note: While ratios provide guidance, every formulation must be validated under actual storage conditions. Cold flow is influenced by humidity, temperature fluctuations, and packaging, so even a 70:30 ratio can fail if the gummy is exposed to high moisture. A high-barrier pouch slows moisture uptake, which buys margin in humid climates. Always conduct stability tests before scaling production.
If you need assistance formulating a stable gummy or optimizing your sugar blend, KorNutra's team can help you fine-tune the ratio to your specific equipment and target texture, while ensuring shape integrity over the product's shelf life.