Understanding Overrun in Ice Cream: What It Is and Why It Matters

Every scoop of ice cream you enjoy owes much of its creamy, smooth texture to a concept called overrun. In ice cream manufacturing, overrun is the measure of how much air gets incorporated into the mix during the freezing and churning process. It directly determines whether a product feels light and velvety or dense and heavy on the palate. For dairy science students and ice cream producers alike, understanding overrun is essential – it affects texture, mouthfeel, product quality, and even business profitability.

What is overrun in ice cream? 🔗

Overrun refers to the increase in the volume of ice cream obtained beyond the original volume of the mix, primarily due to the incorporation of air during the freezing process. It is expressed as a percentage of the original mix volume. For example, if you start with 1 litre of ice cream mix and end up with 1.5 litres of finished ice cream, the overrun is 50%. The air that gets whipped in during churning is what creates this volume expansion.

Without any air, ice cream would be an extremely dense, hard-to-scoop frozen block. The controlled incorporation of air transforms it into the smooth, scoopable product consumers expect. This is why overrun is sometimes informally referred to as the “fluffiness factor” of ice cream.

How is overrun calculated? 🔗

There are two standard methods for calculating overrun – by volume and by weight. Both are widely used in commercial ice cream production.

Calculation by volume 🔗

This is the more straightforward method, typically used at the plant level. The formula is:

% Overrun = [(Volume of ice cream – Volume of mix) / Volume of mix] × 100

For instance, if 10 litres of mix yield 19 litres of ice cream, the overrun would be: [(19 – 10) / 10] × 100 = 90%. This means the final product has 90% more volume than the original mix, with that additional volume consisting almost entirely of air.

Calculation by weight 🔗

Since measuring exact volumes of frozen ice cream can be tricky, the weight-based method is often more practical, especially for checking overrun at the point of production. The formula is:

% Overrun = [(Weight of mix in a container – Weight of same volume of ice cream) / Weight of same volume of ice cream] × 100

For example, if 100 ml of mix weighs 110 g and 100 ml of frozen ice cream weighs 55 g, the overrun is: [(110 – 55) / 55] × 100 = 100%. A 100% overrun means the product is half mix and half air by volume.

Many manufacturers develop overrun tables – pre-calculated charts that correlate the weight of a fixed-volume container of ice cream with specific overrun percentages. This allows production staff to quickly check overrun by simply weighing a cup of freshly drawn ice cream rather than performing calculations each time.

Why does overrun matter? 🔗

Overrun is not just a number on a production sheet. It has a direct and measurable impact on three critical aspects of ice cream: texture and mouthfeel, product quality, and profitability.

Impact on texture and mouthfeel 🔗

The amount of air in ice cream fundamentally shapes how it feels in the mouth. Too little overrun (below about 20-25%) produces a product that is overly dense, heavy, and difficult to scoop. It lacks the characteristic lightness consumers associate with good ice cream. On the other end, excessive overrun (above 100-120%) makes ice cream feel thin, airy, and insubstantial – it melts quickly and lacks richness.

Research published in the Journal of Dairy Science has shown that overrun level affects not only air cell size but also ice crystal growth and product hardness during storage. Ice creams with higher overrun tend to have smaller initial air cells due to greater shear forces during manufacturing, which contributes to a smoother, creamier texture.

Impact on product quality and consistency 🔗

Maintaining consistent overrun from batch to batch is critical for quality control. A batch at 60% overrun will taste and feel noticeably different from one at 100% overrun, even when both use the same ingredients. This is why commercial producers invest in precise freezing equipment and regularly monitor overrun during production runs.

The distribution of air cells within the ice cream also matters. A uniform distribution of small air cells results in creamier, slower-melting ice cream, while uneven air distribution can create inconsistent texture within the same container.

Impact on profitability 🔗

From a business standpoint, overrun directly affects how much finished product you get from a given quantity of mix. If you achieve 100% overrun, you are effectively doubling the volume of your output from the same raw materials. This has obvious cost implications. However, pushing overrun too high to maximise volume will compromise quality and can lead to customer dissatisfaction. The goal is to find the sweet spot where quality and economics are both optimised.

As the International Dairy Foods Association notes, “superpremium” ice cream tends to have very low overrun with high fat content, while economy products typically have higher overrun. Consumers can often sense the difference, which is reflected in pricing and brand positioning.

Typical overrun levels in different ice cream products 🔗

Different categories of frozen desserts are produced at different overrun levels, based on their intended quality tier and format:

Premium/superpremium ice cream: Typically 25-50% overrun. These products are dense, rich, and command higher prices. The low overrun contributes to an intense flavour experience and heavy mouthfeel.

Standard ice cream: Usually 70-100% overrun. This is the range most commercial ice cream falls into, offering a good balance between creaminess and lightness.

Economy ice cream: Often 100-120% overrun. Higher air content makes the product lighter and allows more servings per unit of mix, keeping costs down.

Soft serve ice cream: Typically 30-60% overrun depending on the machine type. Gravity-fed machines generally yield about 25-35% overrun, while pressurised machines can achieve 65% or more. For best quality soft serve, a 50-60% overrun is generally recommended.

Gelato: Usually 25-40% overrun. The low air content is a defining characteristic of gelato, contributing to its dense, intense flavour profile.

Factors affecting overrun in ice cream 🔗

Achieving the desired overrun level is not automatic – it depends on a range of interrelated factors related to both the mix composition and the processing conditions.

Mix composition 🔗

Fat content: Fat globules play a key role in stabilising air bubbles. During churning, fat globules partially coalesce around air cells, helping to hold them in place. Mixes with optimal fat levels (typically 10-16% for premium ice cream) generally achieve better, more stable overrun.

Protein content: Proteins, especially milk proteins like casein and whey, act as foaming agents. They migrate to the surface of air bubbles and form a film that helps prevent bubble collapse. Higher protein levels generally support better air retention.

Total solids: The total solids content of the mix affects its viscosity during churning. A properly formulated mix with adequate total solids will trap and retain air more effectively than a thin, watery mix.

Emulsifiers and stabilisers: Emulsifiers like mono- and diglycerides promote fat destabilisation during freezing, which improves the ability of fat to surround and stabilise air cells. Stabilisers such as guar gum and locust bean gum increase mix viscosity and reduce free water, both of which help maintain uniform air incorporation.

Processing conditions 🔗

Freezer type and dasher speed: The design and speed of the dasher (the mixing blade inside the freezer) directly influence how air is incorporated. Higher dasher speeds increase shear stress, breaking larger air bubbles into smaller ones and increasing the extent of fat destabilisation – both of which improve texture.

Drawing temperature: The temperature at which ice cream is drawn from the freezer matters. If it is too warm, the mix will not hold air effectively. If it is too cold, the mix becomes too viscous for proper air incorporation. Most commercial operations draw ice cream at approximately -5°C to -6°C.

Freezer pressure: In pressurised (pump-fed) machines, the pressure level controls how much air is forced into the mix. Higher pressure settings allow greater air incorporation compared to gravity-fed systems.

Sharpness of scraper blades: Worn or dull scraper blades reduce the efficiency of heat transfer on the freezer barrel wall, which slows freezing and impairs uniform air distribution.

Problems caused by incorrect overrun 🔗

Both too much and too little overrun create distinct quality defects in the finished product.

When overrun is too low 🔗

The ice cream becomes excessively dense and heavy. It is difficult to scoop, feels wet or soggy on the tongue, and lacks the characteristic light, creamy texture that consumers expect. From a cost perspective, low overrun means less product from the same amount of mix, reducing output and profitability.

When overrun is too high 🔗

The product becomes snowy, fluffy, and lacks body. It melts very quickly, does not retain its shape well, and the flavour impact is reduced because there is proportionally less mix (and therefore fewer flavour compounds) per bite. High-overrun products can also suffer from structural instability during storage and distribution, particularly if subjected to temperature fluctuations.

Common causes of failure to achieve desired overrun 🔗

Several issues can prevent a manufacturer from reaching the target overrun: excessively high drawing temperature, worn dasher blades, low total solids in the mix, insufficient aging of the mix before freezing, and mechanical issues with the freezer equipment. Monitoring overrun regularly during production – using weight-based checks – helps catch problems early before large quantities of substandard product are made.

Regulatory aspects of overrun 🔗

While overrun itself is not always directly regulated as a percentage, it is indirectly controlled through weight-per-volume standards. In the United States, the FDA mandates that ice cream must weigh at least 4.5 pounds per gallon, which effectively caps the amount of air that can be incorporated. Products exceeding this air limit may need to be labelled as “frozen dairy dessert” rather than ice cream.

In India, the FSSAI standards set compositional requirements for ice cream – minimum 10% milk fat, 3.5% protein, and 36% total solids – which indirectly influence the range of achievable overrun. While FSSAI does not prescribe a specific overrun limit, the compositional standards ensure that the base mix has enough substance to produce quality ice cream regardless of the overrun level chosen.

Controlling overrun in practice 🔗

In a commercial setting, overrun control requires attention to every stage of the production process. It begins with proper mix formulation – ensuring adequate fat, protein, total solids, and appropriate levels of emulsifiers and stabilisers. The mix must be properly aged (typically 4-24 hours at 2-4°C) before freezing, allowing fat crystallisation and protein hydration to occur.

During freezing, operators should maintain consistent refrigerant flow, check dasher blade condition, and regularly weigh samples of ice cream drawn from the freezer. Many plants use a standard-volume cup and a precision balance to perform quick overrun checks. Any deviation from the target overrun should trigger an investigation into possible causes – temperature drift, worn blades, or changes in mix composition.

For products with particulates like nuts, fruits, or cookie pieces, overrun calculations need to account for the volume and density of these inclusions. Particulates that do not incorporate air themselves will dilute the overall overrun of the package, so the base ice cream may need to be produced at a slightly higher overrun to compensate.

What do you think? Given that higher overrun can lower production costs while potentially reducing product quality, how should ice cream manufacturers decide on the right overrun level for their target market? And as a consumer, can you tell the difference between a dense, low-overrun ice cream and a lighter, high-overrun product?

References

1. https://books.lib.uoguelph.ca/icecreamtechnologyebook/chapter/overrun-calculations/
2. https://www.specializedequip.com/overrun
3. https://www.palsgaard.com/en/food-emulsifiers-and-stabilisers/insights/ice-cream/how-to-create-high-overrun-ice-cream-without-compromising-on-quality/
4. https://www.sciencedirect.com/science/article/abs/pii/S0958694603001973
5. https://www.idfa.org/ice-cream-labeling
6. https://slicesconcession.com/what-is-overrun-why-does-it-matter-when-making-soft-serve-ice-cream/
7. http://dairy-technology.blogspot.com/2014/01/overrun-in-ice-cream.html
8. https://pubmed.ncbi.nlm.nih.gov/29388677/
9. https://www.mass.gov/news/i-scream-for-ice-cream-law
10. https://www.foodresearchlab.com/insights/regulation-updates/fssai-regulations-diary-based-confectionaries/