Ice Cream: To Stabilize, Or Not Stabilize?

Ice cream stabilizers are an issue that I’ve grappled with for a long time. I want to believe that stabilizers are never necessary and that ice cream should only contain milk, cream, sugar, eggs and flavoring. There exists the perception that stabilized ice cream mixes are “pumped full of chemicals and air”, not “all-natural”, and therefore “lower in quality”. In some respects, the naysayers are right. Look at any label of supermarket brand ice cream and you’ll see “milk, sugar, milk solids, corn syrup…” Cream is often a distant third on the ingredient list. So what’s giving ice cream with so little cream its creamy texture and mouthfeel? In a word: stabilizers. And this is where stabilizers get their bad rap, and why some pastry chefs proudly proclaim that they never use stabilizers in their ice creams and sorbets. Perhaps they should reconsider such a militant stance.

From a chemical perspective, ice cream is an unnatural food. Chris Clarke, author of The Science of Ice Cream, describes ice cream as “made up of little ice crystals and air bubbles and fat droplets, all sort of glued together by a viscous sugar solution.” Left to their own devices, these elements would not mix, so ice cream must be frozen and whipped at the same time and kept frozen to protect this artificially induced arrangement. The moment the ice cream warms, it loses its structure forever and heat shock sets in. Every time you remove ice cream from the freezer, it warms, melts, and re-freezes slowly which promotes the growth of large ice crystals. Over time, the lactose in milk may separate from the ice cream and is perceived as grittiness on the tongue, a phenomenon known in manufacturing circles as “lactose crystallization”.

Stabilizers prolong the shelf life of ice cream by absorbing and binding the water in an ice cream mix. The water is now unavailable to form ice crystals and the gelling action adds viscosity to slow down melting. The ice cream is now less prone to heat shock. Stabilizers also act as emulsifiers to prevent the water and fat from separating which also contributes to prolonged shelf life and uniform melting. The overall effect of stabilizers is the ice cream has a smooth mouthfeel and can handle small temperature fluctuations without separating, becoming gritty or icy.

The anti-stabilizer camp of pastry chefs argue that a pastry chef should be able to formulate an ice cream that is smooth and creamy without resorting to “chemicals” and “artificial means”, although the truth is that most stabilizers are extracted from natural sources, such as seaweed and tree resins. They also reject stabilizers because they add a firm, chewy, and unpalatable texture to ice creams, and this is true when the wrong stabilizer is used or used in excessive amounts. Pro-stabilizer pastry chefs argue that stabilizers are a necessity when working in a hot kitchen (as most kitchens do not have a separate pastry workspace) and, in some circles, pastry chefs argue that uniform melting allows the tongue to perceive flavors more intensely.

In the ongoing debate, it’s rarely acknowledged that pastry chefs are using the same stabilizing ingredients as the manufacturers churning out economy ice cream, yet they are lauded for the quality of their work while commercial ice cream manufacturers are denigrated for their deceit. The difference between the two camps seems to be one of intent. Manufacturers use stabilizers in great quantities to replace high cost ingredients (milk, cream, and eggs) with low cost ingredients (skim milk, milk solids, and air) so that the loss in quality is not perceived. Commercial ice creams are churned in huge batches and stabilizers enable them to survive the rigors of packing, storage, and transport to the store and eventually your home freezer. However, the pastry chef’s intent is to stabilize the ice cream mix when extra water or fat is introduced with flavorings and maintain its frozen texture and scoopability when the temperature fluctuates, as it will when freezers are opened and closed in a hot restaurant kitchen.

Ice Cream Stabilizers

Guar Gum: harvested from seeds of guar bush; adds body and hydrates in cold water; does not protect against heat shock and is used in conjunction with other stabilizers.

Locust Bean Gum harvested from the seeds of the carob tree and also known as carob bean gum; promotes aeration and creates less gummy texture than guar gum in ice cream; must be heated to 170 degrees Fahrenheit for full hydration; best used in ice creams.

Carageenan: an extract of Irish moss and red seaweed; prevents milk from separating into solids and liquids; available in kappa, iota, and lambda form

Xanthan Gum: synthesized from glucose (or sucrose) that’s been fermented with a bacteria; strong thickening and emulsifying properties makes it popular for use in lowfat ice creams; adds a chewy texture to ice cream when used in large quantities and is generally used in conjunction with other stabilizers.

Sodium Alginate: extracted from ocean kelp; dissolves between 155 and 160 degrees Fahrenheit; adds a unique body and texture compared to other gums but is relatively expensive; best used in ice creams.

Carboxymethylcellulose (CMC): extracted from vegetable cellulose; inhibits crystallization and protects against heat shock; best used in sorbets and sherbets.

Agar-agar: extracted from red algae; requires boiling and absorbs large quantity of water but forms a hard gel ; best used in sorbets and water-based frozen desserts.

Polysorbate 80: derived from sorbitol (derived from glucose or sucrose); used as an emulsifier in ice cream to create smooth mouthfeel and inhibit melting; best used in ice cream.

Mono- and di-glycerides: derived from vegetable fats (palm, soy, canola) and act as emulsifiers.

Strawberry ice cream is an example of an ice cream that can benefit from the addition of stabilizers.  Strawberry’s high water content makes it notoriously difficult to produce a creamy strawberry ice cream that tastes like fresh strawberries but doesn’t turn icy once frozen. The water content can be reduced by cooking the strawberries, although the fruit will lose its fresh flavor. The water content can also be reduced by increasing the fat content although this will mask the fruit’s flavor. Adding milk solids will also reduce the water content but increase the probability of lactose crystallization during storage. Increasing the sugar content will bind available water although it will mask the strawberry flavor and inhibit freezing. Brown butter ice cream is another flavor that can benefit from the addition of a stabilizer as the additional fat tends to separate and form chunks during freezing and its high dairy content favors lactose crystallization.

As useful as they are, there also exists an over-reliance on stabilizers to make up for poor technique (spinning bases before they fully ripen), improper handling (tempering ice cream at ambient temperatures), and unbalanced formulas. It’s also important to note that other elements can contribute to stabilizing ice cream without relying on stabilizers: naturally occurring milk proteins and emulsifiers, pasteurization, and freezing. Egg yolks are renowned for their emulsifying properties in mayonnaise and hollandaise sauces and in ice cream, it’s no different as it’s the water (in milk) and fat (in cream) that don’t want to mix.  Gelatin is the original—and all-purpose—stabilizer. Although it requires two to four hours of aging to fully gel, gelatin inhibits crystallization and increases viscosity in ice creams, sherbets, and sorbets. Pectin is usually extracted from apples and citrus fruits, dissolves better in hot solutions, and is best used in sorbets.  Cornstarch is another alternative to commercial stabilizers although it is not freezer-stable and will degrade over time. Pasteurization denatures milk proteins and allows them to bind water, reducing its availability to form ice crystals, and the need to use stabilizers. The quality of an ice cream machine is often overlooked: the quicker the freeze and the faster the churn, the smaller the ice crystals and the smother the mouthfeel of the ice cream. (This is what makes the PacoJet system so effective; its blades rotate at high speeds to create micro-particles that are so small that the tongue perceives the ice cream to be perfectly smooth and creamy.)

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Making Ice Cream (and Sorbet) Without Stabilizers

• Cook base thoroughly during pasteurization.
• Ripen the ice cream base by chilling for at least four hours before churning. The base will thicken considerably meaning that less water is available to form ice crystals.
• Use whole fruit. Juicing fruit (esp. for sorbets) leaves behind their most valuable assets—the fiber and pectin.
• Use fruits naturally high in pectin (grapes, apples, citrus fruits, quince) and fiber (figs, mango, rhubarb) to thicken your base.
• Egg whites can stabilize small amounts of fats (such as olive oil) and lighten texture. Use pasteurized egg whites, meringue powder, or cooked meringue

Pointers for Success

• Use a balanced formula and adjust for varying water content and strength of flavors.
• Use a quality ice cream machine that churns the ice cream quickly and evenly to prevent ice crystals from forming. A perfectly prepared base spun in a sub-par machine will make sub-par ice cream.
• Replace the blades on your machine before they wear out.
• Respect temperature. Keep your storage freezer below 0 degrees Fahrenheit and temper your ice cream in the fridge, not on the counter.
• Churn only what you will use within 24-48 hours.

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For basic ice cream flavors, like vanilla and chocolate, or flavors based on dried teas and spices, using a balanced formula with quality ingredients and observing proper freezing and handling techniques eliminates the need for stabilizers. Once recipes include high water ingredients like fresh fruit, there is no denying that stabilizers can enhance the ice cream’s mouthfeel and handling properties. But perhaps the conversation surrounding stabilizers should focus less on whether they are good or bad, and more on how we can use stabilizers as natural support in creating new ice cream flavors and perfecting old favorites. What do you think?