Gelato vs. Ice Cream
Gelato vs. Ice cream
How are they different?
What is gelato?
Simply put, “gelato” is the Italian word for ice cream. Nevertheless, ask two chefs to explain the defining characteristics between the two and you will get two different answers. My own feeling is that there is a distinct difference between the two, but that that difference cannot be explained by appeals to authority or authenticity. Rather, from my point of view, the difference between the two desserts is largely cultural and a result of what ingredients are readily available in Italy and how the Italians produce, sell and eat their ice cream.
All gelato experts would agree that gelato is served and stored in a range between 10-22°F. In this temperature range, the frozen custard is soft and pliable, served in cups with a flat paddle serving spoon instead of a rounded half circle scoop. Generally, gelato is churned and served on the same day. By comparison, ice cream in the United States is churned and then stored for a day or a week or a month at temperatures below -5° F before being served. And the ice cream is generally served between 0-5°F as scoops of roundish balls. Before I continue to discuss some of the other defining characteristics of gelato and particularly the gelato made on the Sweetcycle, let me first explain how ice cream custard freezes in an ice cream machine (hand cranked, foot cranked and electric) and how storing it in the freezer effects the overall texture of the finished product.
What is ice cream
Ice cream is a complicated emulsion of water, sugar, protein, fat and flavoring, with the special and unique properties of water acting as the principal player in the transmutation of custard into a frozen confection.
Controlling ice crystal formation, both in terms of size and number, is the essential secret to good ice cream and for sorbet as well. When pure water freezes, at 0 C (32F), it forms hexagonal-shaped crystals with sharp edges that, if left alone, can grow quite large in size, becoming visible to the eye and clearly discernable on the tongue. In ice cream, neither large size nor sharpness is desirable, so finding ways to make the crystals small enough so that we don’t taste or identify the individual crystals is the name of the game.
Before considering how the ingredients effect ice crystal formation, let’s look briefly at how ice cream machines function and their effect on ice crystal formation. These machines simultaneously chill and whip custards by rapid spinning with a sharp blade. In general, it’s the combination of a strong cooling mechanism, the speed, sharpness and shape of the whipping blade (called a dasher) and the amount of air pumped into the mixture that produces smaller ice crystals that gives the final product a smoother texture.
What role do the ingredients play? Adding soluble ingredients – like sugar or salt – lowers the freezing point of water. The lower the freezing point of a fluid, the more ice crystals that form (in a given volume) during freezing, and the smaller each individual crystal becomes. That is, sugar directly results in smaller ice crystals and improved texture. Liquid sugars (or invert sugars) – honey, corn syrup and its derivatives, caramel, maple syrup, malt syrup and molasses, for example – lower the freezing point even more powerfully. The addition of liquid sugars helps ice cream bases and sorbet bases obtain a potentially smoother texture than it would with just ordinary table sugar (sucrose).
Other ingredients that effect the freezing process are proteins and other gelling agents. Under specific conditions (heat and or agitation), proteins absorb water, forming a gel, preventing ice crystals from forming. Gelling agents like locust bean gum and rice starch also hold water in a gel. Water molecules locked in a gel cannot migrate over to existing ice crystals – increasing their size – or form their own ice crystals at normal freezer temperatures.
The last ingredient that effects ice crystal formation is fat. Fats are large molecules that physically block ice crystals from growing in size. In addition, whipped fat is an excellent vehicle for holding air pockets, and air lightens texture by increasing volume. Too much cream, however, can lead to a grainy ice cream – the dasher (whipping blade) causes the high concentration of fat molecules to coalesce (tiny flecks of hard butterfat), abandoning the air pockets they surround and breaking the creamy emulsion usually created in ice cream.
So, ice crystal formation is effected by the type and quality of the ice cream machine, the chilling mechanism in the ice cream machine, the ingredients in the ice cream custard and, also, by the storage time. Ice crystals in ice cream increase in size over time. The longer churned ice cream sits at freezing temperatures, the larger the ice crystals become. Over time water migrates out of gels and onto existing ice crystals. You will see mono and diglycerides on the ingredient list in commercial ice creams stored in the freezer at the supermarket, because these kinds of food additives prevent the migration of water out of gels, keeping ice cream smooth and creamy for longer periods of time.
Gelato on the sweetcycle
The unique combination of pedal power, the Sweetcycle recipe and the design and attributes of the Immergood ice cream churn produce a frozen dessert that, in my mind, defines gelato.
Gelato from the Sweetcycle is churned, chilled and stored, with ice and salt, keeping the temperature between 15-25 F. I don’t use compressors, freezers or blast chillers to chill the churned custard. I serve the gelato 60 minutes after it has been churned because pedalers want to eat it right away. And freshly churned ice cream is absolutely delicious. The gelato recipes for the Sweetcycle use locust bean gum and rice starch as gelling agents instead of egg yolks. We use more milk than cream, making a lighter ice cream where added flavors are not dulled by the fatty mouth feel of egg yolks and lots of cream.
The Immergood ice cream bucket comes with a very long metal canister that has a central dasher. The long shape of the canister with its narrow diameter makes it possible for a higher percentage of the custard to be constantly exposed to the walls of the canister where the cold mixture of ice and salt have contact with the metal. The dasher has two sharp blades but it also has a central axle with six small rings attached to it. The custard flows through the rings as the dasher turns, increasing the fluidity of the custard. Increased fluidity exposes more of the custard to the exterior of the metal canister where the salt and ice are keeping the temperature below 20 F. Thus, the custard, as it churns, is exposed rapidly to cold temperatures. Rapid chilling reduces ice crystal size, making a creamier product. Your average bicycle pedaler controls the dasher at a perfect speed. It is not slow and constant like most home ice cream machines. But it is not spinning really fast like most commercial machines, which inevitably pump more air into the ice cream. A bicycle powered dasher moves at a rate where the custard is rapidly exposed to cold temperatures, without taking in too much air, thus controlling ice crystal formation and making delicious creamy gelato.
So, the Sweetcycle makes gelato, not ice cream. It is creamy and soft when served between 15-20 F; it is cold, smooth, light and refreshing without any fatty tongue coating mouth feel. And it is absolutely delicious