How Ice Cream Is Made

The Process at a Glance

Whatever recipe you make, the path from ingredients to a scoop follows the same steps. Each one has a job, and skipping or rushing one usually shows up in the texture.

1. Weigh every ingredient in grams.
2. Mix the dry ingredients, so the stabilizer is spread through the sugar.
3. Combine and blend the dry ingredients into the liquids.
4. Heat the mix, to pasteurize it and to activate the stabilizers.
5. Homogenize (optional), to break the fat into smaller droplets.
6. Cool quickly to fridge temperature.
7. Age the mix in the fridge for at least 4 hours.
8. Churn it in the ice cream machine, freezing part of the water and whipping in air.
9. Harden it in the freezer, then temper it to serving temperature.

Each Step and Why It Matters

1. Weigh

Ice cream is a balance of fat, sugars, solids and water, and small changes move it. Weigh everything in grams, including liquids, rather than measuring by volume. Stabilizers are used in amounts of 1–5 g per kilo of mix, so a scale that reads to 0.1 g is worth having.

If your machine holds less (or more) than the recipe makes, scale the recipe in the Recipe Editor instead of rounding by hand: the weight summary bar can set a new mix weight or adjust the recipe to your machine. See Recipe Weights, Scaling & Evaporation.

2. Mix the Dry Ingredients

Stir the sugars, milk powder and stabilizer together in a bowl before they meet any liquid. Stabilizers are used in tiny amounts and swell as soon as they get wet: added on their own, they form lumps that never dissolve. Spread through the sugar, each grain is separated and disperses evenly.

3. Combine and Blend

Add the dry mix to the milk and cream while blending. A high-speed blender works best; a stick blender is the next best thing. Blend on low while you pour the dry ingredients in, then on high for about 30 seconds. If you use egg yolks, add them last on low speed and blend only briefly, so you don't whip in a lot of foam.

4. Heat

Heating does two jobs:

• Pasteurizing. Heating the mix kills harmful bacteria, which matters most when it contains raw egg yolks. Heat slowly while stirring, and don't let it boil.
• Hydrating the stabilizers. Many stabilizers only work fully once they have been heated. Locust bean gum, for example, needs about 85 °C (185 °F), and starches need close to boiling. Others, such as guar and xanthan, work cold. The temperature for each one is in Stabilizers & Emulsifiers.

For most home recipes, heating to 80–85 °C (176–185 °F) covers both jobs. If your recipe needs a stabilizer that hydrates at a higher temperature, such as a starch, heat the milk and cream to near boiling first, then add a little of the hot liquid to the yolks to warm them up gradually (tempering) before you stir them back in.

Evaporation. A mix that is heated in an open pan loses some water as steam, which concentrates everything else. If you weigh the mix before and after heating, enter the weight after heating as the recipe's Final weight (or the loss as Evaporation; the two fields stay in sync), so the calculator works with the mix you actually freeze. Ingredients you add after heating, such as a cold fruit purée, can be marked with the E button so they don't count towards the evaporation. See Recipe Weights, Scaling & Evaporation.

5. Homogenize (Optional)

While the mix is still hot, blend it on high for about a minute. This breaks the fat into smaller droplets, which gives a smoother, creamier texture and helps the fat build structure during churning. Commercial producers use a homogenizer; at home, a high-speed blender gets you part of the way there.

6. Cool Quickly

Bring the hot mix down to fridge temperature as fast as you can. Bacteria multiply quickest between about 5 °C and 60 °C (40–140 °F), so the less time the mix spends there, the safer it is. Fast cooling also helps the texture.

An easy home method: pour the mix into a zip-lock bag, squeeze out the air, and lay it in a bowl of ice water. The flat bag has a large surface, so it cools in a fraction of the time a full pan would take. Then move it to the fridge.

7. Age

Let the mix rest in the fridge, at about 4 °C (39 °F), for at least 4 hours, and preferably overnight. During aging, part of the fat crystallizes, the proteins and stabilizers finish absorbing water, and emulsifiers settle on the fat droplets. An aged mix whips better, holds more air, and melts more slowly. Gelatin in particular needs a long aging time to work properly.

8. Churn

Churning does two things at once: it freezes part of the water into very small ice crystals, and it whips in air. The faster the mix freezes, the smaller the crystals and the smoother the ice cream.

• When it is done. A domestic machine typically stops at around −5 to −7 °C (23 to 19 °F), with roughly half the water frozen. The calculator shows an Extraction temp for every recipe: the temperature at which your recipe reaches the frozen water level you set for extraction (55% by default, in Settings). Recipes with a high PAC reach it at a lower temperature and need longer in the machine.
• Overrun. The air whipped in is called overrun: 25% overrun means 1 litre of mix becomes about 1.25 litres of ice cream. Home machines usually reach 20–40%; more fat, more milk solids and a well-aged mix give more. Set the overrun you get in the recipe's Overrun field, so volumes and densities are calculated correctly.
• Inclusions and ribbons. Add chocolate pieces, nuts, cookies or a ribbon of sauce at the very end of churning or while you fill the container. In the recipe, mark them with the I (Inclusion) button, so they are kept out of the mix calculations for PAC, POD and solids. See Recipe Editor.

9. Harden and Temper

Straight from the machine, ice cream is too soft to scoop and only half frozen. Put it in a pre-chilled container, cover the surface, and move it to the coldest part of the freezer, −18 °C (0 °F) or colder, for several hours. The faster it hardens, the smaller the ice crystals stay.

Before serving, let it warm up to serving temperature: 5–10 minutes on the counter or 15–30 minutes in the fridge is usually enough. Your recipe's Serving temp tells you at which temperature it scoops best. See Understanding Scoopability and Serving Temperatures.

Four Home Methods

All four methods use the steps above; they differ in how the mix is heated. In every method, start by mixing the dry ingredients well in a bowl, and finish by aging and churning.

Classic Stovetop

1. Put the milk, cream and egg yolks in a pan and whisk in the dry ingredients.
2. Heat slowly to 82 °C (180 °F) while stirring.
3. Pour into a zip-lock bag and cool in ice water.
4. Age in the fridge for at least 4 hours, preferably overnight.
5. Churn.

Stovetop with a Blender

1. Put the milk and cream in a blender. On low speed, add the dry ingredients, then blend on high for 30 seconds.
2. On low speed, add the egg yolks and blend briefly.
3. Pour into a pan and heat slowly to 82 °C (180 °F) while stirring.
4. Optional: blend on high for 1 minute to homogenize.
5. Pour into a zip-lock bag and cool in ice water.
6. Age in the fridge for at least 4 hours, preferably overnight.
7. Churn.

Sous-Vide

Gentle and hands-off: the mix can't scorch or curdle, and nothing evaporates.

1. Blend the milk, cream, dry ingredients and egg yolks as in the blender method.
2. Pour into a zip-lock or vacuum bag, weigh it down so it stays under water, and cook at 80 °C (176 °F) for 45 minutes.
3. Optional: blend on high for 1 minute to homogenize, then return the mix to the bag.
4. Cool the bag in ice water.
5. Age in the fridge for at least 4 hours, preferably overnight.
6. Churn.

No-Cook (Cold Process)

The fastest method, for recipes that don't need heat.

1. Use only stabilizers that work cold, such as guar, xanthan or a cold-process blend. See Stabilizers & Emulsifiers.
2. Blend the milk, cream and dry ingredients on high for 30 seconds.
3. Age in the fridge, ideally for at least 4 hours. A shorter rest works, with a slightly less smooth result.
4. Churn.

Food safety: A no-cook mix is not pasteurized, so it must not contain raw egg yolks. Use pasteurized egg yolks or leave the eggs out, and use only pasteurized milk and cream.

Freeze-Then-Spin Machines

Machines such as the Ninja Creami and the PacoJet work the other way round: you freeze the whole mix solid first, then the machine shaves and whips the frozen block into ice cream. Steps 1–7 stay the same; instead of churning, pour the cooled mix into the machine's container, freeze it, and process it when you want to serve.

Because the block is shaved from very cold storage and warms up during spinning, these machines suit recipes that are softer than a classic hard-scoop ice cream. The calculator's guidance for them is in Understanding Scoopability and Serving Temperatures.

Write Down Your Own Method

Once you have a method that works for you, store it with the recipe: the Instructions card in the Recipe Editor holds numbered steps in groups, such as "Base mix", "Ageing" and "Finishing", and they appear on every recipe card, print and share. See Recipe Instructions.

Related Articles

• Stabilizers & Emulsifiers
• Recipe Weights, Scaling & Evaporation
• Understanding Scoopability and Serving Temperatures
• Freezing Point Depression
• Ice Cream Science - The Short Version
• Settings