Center for Dairy Research logo

Pizza Evaluation

Pizza Evaluation

The following outlines the internal evaluation protocol CDR uses to assess cheese functionality on a pizza. The temperatures and scales shown are only examples. It is important for each organization to develop their own internal parameters based on their consumers' wishes. CDR's internal protocol utilizes a Lincoln Impinger oven. Each pizza also has the same amount of cheese, measured by mass (200g-300g).

You can download a PDF version of this page by clicking the following link:

Pizza Evaluation Protocol

Blistering and Melt Attributes

Out of the oven

When the cheese comes out of the oven, a picture is taken of the pizza’s surface. The camera is kept perpendicular to the plane of the pizza surface. A temperature probe is inserted into the hot melted cheese. The normal range of starting maximum temperatures is ~208-210°F. Immediately after temperature probe is inserted, blistering sensory characteristics are assessed.

Blister quantity and blister color are both assessed now. In addition to these evaluations, other notes could be made for color variations on surface. The “background color” (unblistered portion) can vary from very white to intense yellow in some cases.

  • Blister Color: Intensity of the brown hue of the blisters. Related to Maillard browning reactions and burning of the cheese.
  • Blister Quantity: Amount of the surface covered by blisters. Related to protein behavior and cheese flow.

This is also a good time to evaluate how complete the cheese melted. This is called degree of shred melt, also known as “shred identity”.

  • Degree of shred melt: The degree to which the cheese shred melts. Related to cheese composition and nature of flow agents present.

Other Visual Characteristics


As the cheese begins to cool it is important to assess the presence of free oil and skinning. These are both highly temperature dependent attributes, therefore it is important to measure them at a consistent temperature between evaluations. Here we use 205°F.

  • Free oil release: Amount of free oil on the surface of the melted cheese. Related to cheese composition, fat content, and protein behavior.
  • Skinning: Thickness of the surface layer of solidified cheese on the pizza. Related to cheese composition and protein behavior.

In addition to these attributes, you could also assess any “flow off crust” that is occurring. Older, soupy cheese can sometimes melt so much it begins to flow off the crust onto the pan.

Stretch Attributes


Stretch attributes are usually assessed when the cheese gets a little cooler (but not cold). Cheese that is too hot is so low in viscosity that it offers very little resistance when stretched and doesn’t give a clear picture of how the cheese might behave. Here, we stick a tine of a fork into the melted cheese and then pull up.

  • Strand thickness: Width of a cheese strand at 3 inches of height, when the strand has been pulled to 6 inches. Related to protein behavior.
  • Mean strand length: Indicator of cheese stretch-ability. Related to protein behavior.
Stretch Scale

Other stretch characteristics that can be assessed are related to how much force it takes to pull a strand of cheese from the pizza surface. We call this “force to stretch”. Some cheeses offer very little resistance, while others require quite a bit of force. With enough force, “tenting” may occur. Which is a tee-pee shape of melted cheese while trying to pull a cheese strand.


Texture Attributes


Once the cheese reaches a suitable eating temperature, a piece of the cheese can be tasted and texture attributes can be assessed. These are also very temperature dependent, so having a uniform sampling temperate is crucial.

  • Cohesiveness of mass: Degree to which the chewed mass holds together or is broken apart after chewing 12-15 times. Related to protein behavior.
  • Hardness: Amount of force required to completely bite through the sample in one bite using molars/incisors. Related to protein behavior and composition.
  • Chewiness: Total amount of energy needed to break up the sample. How much mastication is required. Related to protein behavior and composition.

There are many other texture attributes that can be measured, such as: adhesiveness, particle size, firmness, etc.

Flavor Attributes


Again, temperature is important. Warmer cheese is usually easier to assess for flavor. This is due to increased volatility at higher temperatures. There are many possible flavors/tastes that can be present in the cheeses. A few are summarized in the table below:

SaltBasic taste sensation elicited by table salt.0.5% salt solution
AcidBasic taste sensation elicited by acids.0.08% lactic acid solution
BitterBasic taste sensation elicited by caffeine.0.05% caffeine solution
ButteryAromatics commonly associated with natural, fresh butter.40 ppm diacetyl in PG
ButyricAroma and flavors associated with butyric acid, cheesy, baby-breath/vomit.Sharp provolone
MetallicFlavor and sensation of presence of metal in mouth, reminiscent of sucking on coins.Canned pineapple juice