CMC in Ice Cream: What Cellulose Gum Does, Dosage and How to Use It

CMC (sodium carboxymethyl cellulose, labelled as cellulose gum or E466) is a stabiliser for ice cream. It binds water and thickens the mix, so ice crystals stay small during freezing and storage. The ice cream feels smoother, melts more slowly and evenly, and turns less icy when the freezer temperature goes up and down.

CMC dissolves in cold liquid, so it works in hot-process and cold-process mixes alike. It is typically tested at 0.1–0.2 % of the mix, which is 1–2 g per kilogram, together with a small amount of carrageenan to prevent whey separation. Use a food-grade CMC of ≥ 99.5 % purity.

What CMC does in ice cream

• It raises the viscosity of the mix, which gives body and helps the mix hold air during freezing.
• It binds free water, so less water is available to grow into large ice crystals.
• It slows the growth of ice crystals when the product warms and refreezes during transport and storage, which is known as heat shock.
• It gives a smoother texture and a slower, more even meltdown.
• In sorbets, water ices and ice pops, it supplies the body that fat and milk solids give to dairy ice cream.

CMC does not replace fat or milk solids, and it does not emulsify. Its job is to control the water phase. It has no taste or smell of its own at the levels used.

How much CMC to use in ice cream

The total stabiliser in an ice cream mix typically falls around 0.2–0.5 %. Within that, CMC is typically tried at 0.1–0.2 % of the mix when it is the main stabiliser, and at less when it is blended with guar gum or locust bean gum. In practical terms, 0.1–0.2 % is 1–2 g of CMC per kilogram of mix. Sentai's general starting range for food-grade CMC is 0.1–0.5 % of the formulation.

How to add CMC to the mix

1. Weigh the CMC and dry-blend it with at least five times its weight of sugar.
2. Add the blend slowly to the milk or water under strong stirring. Never tip CMC powder into still liquid.
3. Keep stirring until no particles are visible. CMC dissolves in cold liquid; warm liquid makes it faster.
4. Pasteurise and homogenise the mix as usual.
5. Age the mix cold, at 4 °C or below, for at least four hours so that the stabiliser hydrates fully, and then freeze it.

CMC compared with other ice cream stabilisers

CMC, stabiliser blends and emulsifiers: how they differ

Many ice cream makers buy a ready-made stabiliser blend instead of single gums. In Brazil these blends are sold as liga neutra. A typical blend combines guar gum and CMC, sometimes with xanthan gum, tara gum or carrageenan, and is diluted with sugar or starch so that small amounts are easy to weigh. CMC is therefore one of the active ingredients of such a blend, not a substitute for it. Dose a blend as its pack says, because the gum content varies; dose pure CMC at the 0.1–0.2 % given above.

An emulsifier is a different ingredient with a different job. Emulsifiers such as mono- and diglycerides of fatty acids or lecithin act on the fat: they help it disperse and help the mix hold air, which gives a creamier, lighter ice cream. Stabilisers act on the water. Most recipes use both, and one does not replace the other.

CMC in ice pops, water ices and milk ice pops

Ice pops go by many local names: bolis and paletas de hielo in Mexico, bolis in Colombia, marcianos in Peru, helados de agua in Argentina and Chile, and geladinho, sacolé or picolé in Brazil. A water-based ice pop has no fat or milk protein, so the stabiliser does more of the work.

CMC keeps the ice crystals fine, so the pop is smooth rather than coarse or sandy. It thickens the mix, so the sugar syrup and the colour do not drain to the bottom of the bag or the tip of the mould before the pop is frozen, and it slows dripping as the pop melts.

For water-based ice pops, CMC is typically used in the upper part of the 0.2–0.5 % range, roughly 3–5 g per litre of mix, because there is no fat or milk to give body. Milk-based pops, such as bolis de leche or geladinho cremoso, behave like ice cream and typically need 0.1–0.2 %, or 1–2 g per litre. If you use a stabiliser blend such as liga neutra, follow the dose on its pack, because the blend is diluted with sugar or starch.

1. Dry-blend the CMC with at least five times its weight of sugar.
2. Whisk the blend into the cold juice, water or milk and keep stirring until no particles remain.
3. Let the mix rest, cold if possible, for at least an hour so that the CMC hydrates fully; stir again before filling the bags or moulds.
4. Freeze as fast as you can: a blast freezer, or a cold freezer that is not overloaded, gives finer ice crystals.

Which CMC grade for ice cream

Ice cream is close to neutral pH, so a Type 6 food grade (DS 0.75–0.90) is the usual choice. High-viscosity grades give more body per gram: Sentai FH6A (200–500 mPa·s as a 1 % solution), FVH6A-1 (500–2,000 mPa·s) and FVH6A-2 (2,000–5,000 mPa·s). For fruit sorbets and other acidic mixes, a Type 9 grade (DS ≥ 0.90) such as FVH9A-1 keeps its viscosity better at low pH.

All Sentai food grades are ≥ 99.5 % pure and are released against China's food-additive standard GB 1886.232-2016, including its limits for arsenic and lead. Technical CMC made for detergents, drilling or paper must not be used in food.

• FH6A Food CMC
• FVH6A-1 Food CMC
• FVH6A-2 Food CMC
• FVH9A-1 Food CMC

Common problems and what to try

Labelling and regulation

On the label, CMC appears as cellulose gum, as sodium carboxymethyl cellulose or by its number: E466 in the European Union and INS 466 in the Codex system. In the United States it is generally recognised as safe (GRAS) under 21 CFR 182.1745. The permitted levels and the label wording differ between countries, so check the regulation of the market you sell in.

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• Food-grade CMC: grades and specifications