Sensory Evaluation of Dairy Products

What exactly are dried dairy ingredients?

Some you see at the grocery store- things like nonfat dry milk powder or whey protein powder. Others, like milk protein isolate or dry buttermilk, you might never see on the shelf- these are ingredients that are added to other food products to enhance their flavor or nutritional content. If you want to learn more about dried dairy ingredients, the Center for Dairy Research at the University of Wisconsin-Madison has a great slide deck that goes into more detail. You can find it here.

Sensory analysis of dried dairy mostly focuses on the aroma and appearance characteristics of the product. Testers look for a clean milk aroma with no serious defects. Sometimes these products can smell grassy or caramelized, which can indicate problems in the way they were processed.

A good chocolate milk will have a warm, dark brown color that is consistent across the whole sample- there should be no blotchiness, banding of color, or visible graininess to the sample. After checking its appearance, evaluators will assess its aroma using a wheel like the one shown above. The sample should have a distinct chocolate aroma without being too strong or too weak. Any atypical aromas (cardboard, coconut, etc.) are noted. Finally, the judges will taste the milk to evaluate its mouthfeel and taste characteristics. Chocolate milk should be about as thick as whole milk and have a pleasant cocoa taste with a moderate level of sweetness. Evaluators make notes on how they feel the chocolate milk performs with respect to these qualities, and then make notes on any off-flavors they detect in the sample.

Fun fact: Chocolate milk sometimes contains an off flavor that most judges call “bandage” or “band-aid.” It’s exactly what it sounds like- this defect tastes the way a Band-Aid smells! Gross! Bandage defects come from chemical compounds called phenols.

Cheese takes so many different forms that often evaluators use specific terms in order to properly evaluate samples. For example, mozzarella, Swiss cheese, and cheddar each have their own lexicons!

Sensory evaluation of cheese takes three distinct forms:

evaluation by descriptive analysis (DA) panel

professional judging in a competition format

personal evaluation (that’s you!)

Cheese is also often evaluated by professional judges in competitions. These judges are more interested in detecting off-flavors or defects in the cheese as part of their judgement. Have you ever heard of the International Cheese Awards? This competition takes place in the United Kingdom every year, and over 5,000 cheeses get submitted for judging! You can see photos from this competition in the photo gallery at the bottom of this page.

Next time you bite into a piece of cheese, think carefully about what it tastes like, and how it feels in your mouth. Interested in learning more about cheese flavors? Check out the cool infographics in our photo gallery at the bottom of the page!

Ice cream taste tester- otherwise known as the best job in the world!

While it’s easy to say whether you like ice cream or not, an objective judging of ice cream can be difficult since it’s such a complex product. One of the most important characteristics of ice cream is its texture. Ice cream should have a smooth, creamy texture that melts evenly in the mouth. Factors that affect ice cream texture include the amount of air and the size of ice crystals in the product. “Fluffy” ice cream has too much air in it, and “sandy” or “gritty” ice cream contains overgrown ice crystals.

You can evaluate ice cream at home yourself! Next time you eat ice cream, let a bite of it sit on your tongue and observe how it melts in your mouth. Think carefully about the texture- does it seem perfectly smooth or can you feel ice crystals?