Probing Question: What is the difference between ice cream and gelato?

I scream, you scream, we all scream for . . . gelato? Frozen treats used to be a simple summertime pleasure, with the toughest choice being chocolate, strawberry, or vanilla. In many supermarkets today, the frozen dessert aisle is packed with options ranging from imported Italian hazelnut gelato and French grapefruit sorbet to Japanese green tea mochi.

Are all of these products simply ice cream with different names? Or is there a substantive difference between them?

According to Robert F. Roberts, head of Penn State's Food Science Department, there are real similarities among these products, as well as real differences.

"The basis of all frozen desserts is sugar syrup containing various characterizing ingredients and flavors," he says. "When only a flavor -- and no dairy -- is added to the sugar syrup, the product is commonly referred to as a water ice, also known as Italian ice or sorbet." Adding a bit of milk makes the product a sherbet. "Further fortifying the product with some cream and condensed or powdered milk to deliver at least 10 percent fat results in the product we know and love as ice cream."

Where the product is made also makes a difference, he says. Gelato, in its traditional Italian form a very dense product with lower fat than American ice cream, has become more available in the United States over the past 20 years -- but Americans still seem unclear on how it differs from ice cream.

"If you ask a cross-section of American consumers, 'How does gelato differ from ice cream?' the answers will include 'It's like a high-fat, premium ice cream' and 'It's a low-fat ice cream' and 'It can only contain natural flavors,'" he says. The reality is that, in the U.S., what is marketed as gelato can have a variety of compositions. Whereas American-style ice cream tends to be made with a lot of cream, gelato is traditionally made with more milk. In both products, the amount of sugar varies a great deal depending on the brand. However, most gelato is made with fewer egg yolks than are used in ice cream, and is sometimes made entirely without eggs. Roberts explains that in Italy, gelato reflects regional differences. "Sicilian gelato" is the lighter, egg-free version preferred in southern Italy. It is made with milk, cornstarch stabilizers, and fruit. The northern version, first popularized in the Dolomite region, is richer, as it contains both cream and eggs.

If you think it sounds like Roberts has ice cream making down cold, you're right. A member of the Penn State food science faculty since 1991, he maintains a long association with the nation's oldest and most successful creamery, the Berkey Creamery at Penn State. (During 2015, the Creamery will be celebrating 150 years of operation.)

Roberts is also director of the Penn State Ice Cream Short Course. The oldest and largest educational program dealing with the science and technology of ice cream, the Ice Cream Short Course has attracted more than 4,400 participants through the years, from every state except North Dakota and every continent except Antarctica. "The student roster reads like a Who's Who of ice cream," says Roberts. "From mom-and-pop operations to industry leaders, many have traveled to University Park to learn the secrets of ice cream making." Even Ben Cohen and Jerry Greenfield of Ben & Jerry's give credit to a correspondence version of the course, which they took in 1978 before launching their first "Ben & Jerry's Homemade Ice Cream Scoop Shop" in Burlington, Vermont.

With all this experience, is Roberts prepared to offer a definition of ice cream? As opposed to gelato, says Roberts, ice cream manufacturers "have to meet a set of criteria that are found in a document called the Code of Federal Regulations. Two highlights of these standards include that the product must contain no less than ten percent milk fat and no less than twenty percent total milk solids." In fact, he adds, in the United States the only allowed source of fat in the ice cream (other than that found in various flavor inclusions) is milk fat. "It is important to note that this standard varies around the world and that other sources of fat are often employed because they are cheaper or more available," he says. In many countries "American-style ice cream" is known as "dairy ice cream."

Another important component of ice cream, says Roberts, is the amount of air that is whipped into the cream before it is frozen. Incorporating air gives the product a more creamy texture and increases its volume in proportion to the amount of air whipped into it. The increase in volume is called "overrun" and is an important characteristic of the product. Low overrun ice creams have overrun of 20 to 40 percent, meaning enough air was added to boost the volume of the starting mixture by 20 to 40 percent. These products, such as those made by Haagen-Dazs or Ben and Jerry's, are quite dense and creamy. Very high overrun products, with up to 100 percent overrun, are double the volume of the original mixture and have a light and fluffy texture. Berkey Creamery ice cream is a medium overrun product, with 50 to 80 percent overrun. Its texture strikes a balance of creamy and fluffy.

By contrast, gelato has very little to no air whipped in. The traditional gelato "dasher" or paddle moves up and down very slowly, as opposed to the faster circular rotation of the ice cream paddle. Many gelato fans say that, with less tongue-coating fat in the ingredients and less air in the manufacturing, the product's flavors are more intense than ice cream's -- but that's a matter of personal taste, says Roberts.

There are trends in ice cream, as fads in diet and nutrition change over time, he adds. "I began teaching the course in 1999. For the first five years or so, the dietary trend was to get the fat out of foods, resulting in a tremendous drive to reduce the fat content of ice cream. A bit later on when low-carbohydrate diets such as Atkins and South Beach were all the rage, the goal was to get the sugar out. At one point I joked with students that if we take the fat out and then take the sugar out, we might as well call the Ice Cream Short Course the 'Ice Cube Short Course!' "

If American ice cream is a premium product in the global ice cream market, what makes Penn State ice cream extra special? "One of the most important aspects of Penn State ice cream is freshness -- the process moves quickly from 'cow to cone,' " he says. "We like to say that 'our ice cream was grass seven days ago' and it's true! Even though it's a frozen product, ice cream is best when it is first made. You are spoiled for life if you taste ice cream coming off the line!" Another factor that makes Penn State ice cream so good is the relatively warm temperature at which it is served, between 0 and 10 degrees Fahrenheit. This allows for better enjoyment of the flavors in the product, he said.

Perhaps what's most special about Penn State's ice cream is the good times and memories thousands of students and alumni enjoy while getting a dish or cone at the Creamery. At 150 years old, with 750,000 cones and bowls hand-dipped per year, it's clear the Berkey Creamery has found the sweet spot for ice cream success. 

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Last Updated August 25, 2016