How ice cream shops make their ice cream

From pasteurising and ageing the mix through the batch freezer to the display case: which steps and temperatures the regulations require, and why.

Behind every scoop in the display case lie several hours of work and precisely controlled temperatures. Production in an ice cream shop differs from making ice cream at home mainly in the machines and the rules, but the principle is the same. Once you understand it, you’ll see why some home tricks work – and why some steps can’t be skipped.

The steps at a glance

StepWhat happensTemperature and time
1. Preparing the mixcombining milk, cream, sugars, solids, stabiliser–
2. Pasteurisationheating the mix, killing bacteriaaccording to the shop’s process
3. Coolingrapid chillingSK: no more than 7 °C
4. Ageingthe mix rests in the coldSK: 4–7 °C, use within 48 h
5. Freezingbatch freezer, whipping10–15 min
6. Hardeningrapid further freezing in tubsthe colder, the better
7. Storagekept frozen until sale−18 °C or below
8. Display casesaleapproximately −12 to −14 °C

The figures for Slovakia come from Slovak Decree No. 82/2018 Z. z., the freezing times from the textbook by H. D. Goff (University of Guelph), and the display-case temperature is an approximate figure from the Ice Cream Calculator website.

1. The mix: more than milk and sugar

An ice cream mix is carefully balanced. Sugars don’t just sweeten – they lower the freezing point, so the ice cream stays scoopable. According to Goff, sweeteners usually make up 12–16 % of the weight of the mix. Milk solids (proteins) bind water and improve the texture, fat provides creaminess. A small amount of stabiliser slows the growth of ice crystals during storage.

Professionals usually calculate the mix from a formula so that the ice cream has the right firmness at display-case temperature. The calculations in zmrzka’s recipes serve the same purpose.

2 and 3. Pasteurisation and rapid cooling

The mix is heated to kill pathogenic bacteria. Straight afterwards it must be cooled quickly so that it doesn’t stay long at temperatures where bacteria thrive. Slovak Decree No. 82/2018 Z. z. requires the mix to be cooled to no more than 7 °C.

Did you know?

According to Goff, after pasteurisation the only protection against new contamination is sanitation and hygiene. A pasteurised mix can easily be contaminated again – by utensils, hands or a poorly cleaned machine.

4. Ageing the mix

The chilled mix rests in the cold, at 4–7 °C under the Slovak decree, usually for at least 4 hours or overnight. While ageing:

  • the fat crystallises, which later helps with whipping,
  • proteins and stabilisers become fully hydrated,
  • the mix thickens and takes up air more easily.

Goff notes that an “unaged” mix shows up as a poorer texture after freezing. Ageing also has an upper limit: in Slovakia, a shop must discard any mix that isn’t used within 48 hours.

Tip

The same goes at home. Let the mix age in the fridge for at least 4 hours, ideally overnight, and use it within two days.

5. Freezing in the batch freezer

The heart of an ice cream shop is the batch freezer – a compressor-cooled cylinder with a rotating dasher fitted with scraper blades. The blades scrape the frozen layer off the wall while air is whipped into the mix. According to Goff, one batch usually takes 10–15 minutes.

What comes out of the machine is ice cream in which roughly half of the water is frozen. It has the consistency of soft serve. To be scooped, it still has to be hardened.

Speed matters. The faster the mix freezes, the smaller and more numerous the ice crystals and the smoother the ice cream. That’s why the mix goes into the machine as cold as possible.

Air in ice cream

During freezing, air is whipped into the ice cream (this is called overrun). Goff notes that up to half the volume of ice cream can be air. Artisan ice cream generally contains less air, which is why it is denser. This is also why litres and kilograms of ice cream can’t simply be converted into one another.

6. Hardening

Ice cream from the machine goes straight into tubs and into a blast freezer or a very cold freezer. Here too, the faster, the finer the crystals. According to Goff, ice cream is stable below about −25 °C and the crystals don’t grow. Above this temperature they grow faster the warmer it is.

7. Storage

Finished ice cream is stored at −18 °C or below – required by both Slovak Decree No. 82/2018 Z. z. and Czech Decree No. 397/2016 Sb. The Czech decree allows a brief rise to no more than −15 °C during transport. The greatest enemy of quality is fluctuating temperature: small crystals melt and the water refreezes onto the large ones, and the ice cream turns coarse.

Warning

Under the Slovak decree, frozen cream (the legal term for ice cream) that has thawed and been refrozen must not be placed on the market. The texture deteriorates and the microbiological risk increases.

8. The display case

In the display case, ice cream is warmer than in storage so that it can be scooped. For Italian-style ice cream the approximate figure is −12 to −14 °C (Ice Cream Calculator). Ice cream in the display case should sell quickly. Every time it warms up and cools down again, its quality suffers.

Hygiene and obligations

Every ice cream shop is a food business. Under EU Regulation No. 852/2004 it must be registered and work according to procedures based on HACCP principles – in other words, it must know the risks in its production and keep them under control.

In 2025 the Czech Agriculture and Food Inspection Authority (SZPI) stated that the main causes of unsatisfactory ice cream samples are poor production hygiene, inadequate cleaning of equipment and failure to follow procedures. With soft serve, a typical mistake is pouring leftover mix back into the machine the next day. The inspectors can ban an unsatisfactory shop from using a machine until it has been cleaned and a new test comes back clear.

Tip

The same principles help at home: pasteurised ingredients, rapid cooling, ageing in the fridge, fast freezing, a steady freezer temperature and a clean machine.

Sources

More articles