Frozen custard

The American egg-rich cousin of ice cream: plenty of yolks, a silky dense texture and little air.

Frozen custard is an American ice cream with a large share of egg yolks. Unlike cream ice cream made with yolks, it is defined by US law: it must contain a legal minimum of egg yolk solids. It is typically made in continuous freezers that whip in little air, and it is served fresh straight from the machine — dense, silky and softer than scooped ice cream.

Compared with French-style cream ice cream, which is also made on a custard base (crème anglaise), the difference lies mostly in the format: custard is not stored until hard but is ready to eat straight away, and it contains enough yolks to meet the US legal definition.

Origin and history

Frozen custard is associated with Coney Island in New York, where the brothers Archie and Elton Kohr started selling it in 1919. It spread after the 1933 Chicago World’s Fair, and Milwaukee is now considered its “unofficial capital”. These details come from the English Wikipedia.

Typical composition

Egg yolk contains 44–48 % solids (Czech NutriDatabáze and USDA). The legal 1.4 % of yolk solids therefore corresponds to about 3 % raw egg yolk in the mix, i.e. around 30 g of yolks per kilogram.

Egg yolk does three things in the mix: its lecithin acts as an emulsifier, its proteins thicken the base when heated, and the ice cream whips better and melts more slowly.

What the law says

The US regulation 21 CFR § 135.110 covers ice cream and frozen custard together. Both must contain at least 10 % milk fat and 20 % total milk solids. Frozen custard must contain at least 1.4 % egg yolk solids; ordinary ice cream contains less. In the US the product is also called “French ice cream” or “French custard ice cream”.

How to make it at home

The basis is a custard base (crème anglaise) — milk, cream, sugar and egg yolks heated while stirring constantly until they thicken.

1. Whisk the yolks with the sugar. Heat the milk and cream and gradually pour them onto the yolks, stirring all the time.
2. Return the mixture to a low heat and stir until it thickens. It must reach at least 71 °C — the threshold the US FDA gives for dishes containing eggs.
3. The custard starts to set at around 70 °C. Above roughly 80 °C the yolks curdle, and just a few degrees too many are enough to produce lumps. The often-quoted 82–85 °C is the upper limit of pastry practice, not a recommendation.
4. Immediately strain the mixture into a bowl set in an ice bath and cool it.
5. Let it age in the fridge for at least 4 hours.
6. Churn in the machine and serve straight away, when the ice cream has the consistency of a thick cream.

A compressor ice cream maker, from which you can scoop the custard straight away, works best. You can also use a freezer-bowl machine or a Ninja CREAMi, but the result will be closer to scooped ice cream. Shops make custard in continuous freezers.

At home it is hard to achieve low overrun and a soft consistency at the same time. Custard from the freezer needs to soften before serving.

Recipes: vanilla custard, chocolate, caramel and custard “concrete”.

The most common mistakes

• Curdled custard — the mixture overheated. With small lumps, straining or blending it immediately may help, but the texture will no longer be ideal.
• Underheated mixture — below 71 °C there is no guarantee that bacteria from the eggs have been killed.
• Strong egg flavour — too many yolks or overheating.
• Mixture too thick — lots of yolks and long cooking; it does not whip well in the machine.
• Hard custard — it was left to harden in the freezer like ordinary ice cream. Custard is best straight away.

How to recognise good custard

• It is dense and silky, smooth, with no lumps or crystals.
• It has a gentle yellowish colour from the yolks, not from colouring.
• It melts slowly into a thick cream.
• The flavour is rich, with a subtle, not dominant, egg note.
• It is served soft and freshly churned — not scraped from a hard block.

How long it takes at home

Total: 1–1.5 hours of active work, 5 hours to a day in all.