1. What is Ice Cream Overrun (Puffing)?

Overrun (puffing) is the percentage increase in volume caused by air incorporated while the mix is frozen and whipped.

Overrun (%) = (Final volume – Mix volume) / Mix volume × 100%

Example: 1 liter of mix becomes 1.6 liters of ice cream, so the overrun is 60%.

2. Effect of Overrun on Ice Cream Quality

Overrun	Texture	Appearance	Cost impact
Low (20–40%)	Dense, heavy, rich flavor	Darker color, compact	Higher mix cost per serving
Medium (40–70%)	Smooth, balanced texture	Full and stable shape	Balanced cost and quality
High (above 70%)	Too airy, foamy	Melts quickly	Lower mix cost, poorer texture

Typical working range: 40–70% for soft serve.

3. Key Factors Affecting Overrun

3.1 Mix Composition

• Low fat or solids give an unstable foam.
• Too little stabilizer or emulsifier lets air escape easily.
• Too much sugar weakens the foam structure.

3.2 Mixing System

Beater design and speed determine how much air is worked in.

3.3 Freezing Conditions

• Freezing too fast leaves too little time to take in air.
• Freezing too slowly lets the foam collapse and forms coarse ice crystals.
• Typical discharge temperature: –6 °C to –8 °C (about 18–21 °F). Check the figure for your model; for example, the SW26RJL-F and GT18RELW product pages list a discharge temperature of ≤–3.5 °C.

3.4 Air Pump or Gravity Feed

• Air-pump models meter air into the cylinder, which allows more precise control of overrun.
• Gravity-fed models rely on the beater to aerate the mix.

For a side-by-side comparison, see gravity vs pump soft serve machines.

4. Business Implications for Operators

4.1 Cost and Yield

Overrun decides how many servings you get from a liter of mix. Raising overrun from 40% to 60% turns 1 liter of mix into 1.6 liters of product instead of 1.4 liters, about 14% more product (1.6 ÷ 1.4 ≈ 1.14). Put the other way, the mix cost per serving drops by about 12.5%. Push overrun much higher and the texture suffers, so treat yield as one factor, not the target.

4.2 Customer Experience

• Balanced overrun gives a soft, creamy texture and stable serving.
• Too low: hard and difficult to dispense. Too high: airy and melts fast.

4.3 Machine Operation and Maintenance

• Keep air settings stable and avoid frequent adjustments.
• Keep air inlets and any air pump clean on the schedule in your machine’s manual.
• Keep the mix level above the air intake.

4.4 Standardization

• Chain stores can set a standard overrun (for example, 65%) and check it with a measured cup.
• Adjust slightly between flavors as needed.

5. Recommended Operating Parameters

Parameter	Suggested value	Purpose
Mix temperature in the hopper	41 °F (5 °C) or below	Food safety and stable freezing
Discharge temperature	About –6 °C to –8 °C (18–21 °F), or your model’s specification	Serving condition
Overrun	40–70%	Balanced cost and texture
Cleaning	Per your machine’s manual and local health department	Hygiene (see Maintenance of Ice Cream Machine)
Air pump maintenance	Per your machine’s manual	Stable aeration

6. Conclusion

Overrun should be controlled, not maximized. Higher overrun lowers the mix cost per serving, but above about 70% the product turns foamy and unstable. Aim for ice cream that is light yet creamy, and measure overrun regularly so every serving is the same. The mix itself matters as much as the machine: see the Soft Serve Ice Cream Mix Selection and Usage Guide.