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 is not just a single number-it depends on total solids content, the type of glucose syrup (DE value), and the presence of other ingredients like pectin or gelatin. However, the classic benchmark is derived 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, more crystalline structure that resists moisture uptake and deformation. Sucrose acts as a "binder" that locks the gummy shape.
For gummy bear-type confections (typically gelatin-based), the critical sugar ratio where cold flow becomes noticeable is approximately 65-70% glucose syrup to 30-35% sucrose. When glucose syrup exceeds 70% of the sugar blend, the product is at high risk for cold flow, 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-these drastically 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+).
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 significantly 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. 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.