Results for “what causes freezer burn” · retrieved September 22, 2026
Freezer burn is caused by moisture loss through sublimation, which occurs when air reaches the surface of frozen food, leading to dehydration and oxidation.
Freezer burn is caused by the dehydration of food through a process called sublimation, where ice crystals on the food's surface turn directly into water vapor without melting. This moisture loss leaves the food surface dry, shriveled, and discolored. As moisture escapes, air fills the resulting gaps, exposing the food to oxygen. This exposure leads to oxidation, which can cause further discoloration and flavor degradation, particularly in meats and high-fat foods. Factors that accelerate this process include inadequate or loose packaging, fluctuating freezer temperatures, and prolonged storage time.
Answer details
Sublimation and Dehydration
Sublimation is the primary mechanism, where ice crystals on the food's surface transition directly from a solid to a gas, causing the food to dry out and become shriveled or leathery.
Oxidation and Exposure to Air
When moisture escapes, air fills the empty spaces, exposing the food to oxygen. This causes oxidation, which can bleach colors, turn meat brown, and negatively impact flavor.
Storage and Packaging Factors
Inadequate or loose packaging allows air to reach the food surface, while fluctuating temperatures and long storage times increase the rate at which moisture is lost.
Freezer Type
Self-defrosting freezers can increase the rate of freezer burn by keeping the air inside the freezer dry, which maintains a strong driving force for moisture to sublimate from the food.
Sources 8
About this answerFreezer Burn and Food Safety • AnswerLine • Iowa State University Extension and Outreach
Have you opened some frozen food to find it has a dry, grayish surface or lots of ice crystals clinging to the surface? This is freezer burn. Freezer burn is simply the result of air coming into contact with food, and while it may not look appetizing, it is usually safe to eat....The phenomenon of freezer burn happens when tiny ice crystals on the food’s surface evaporate directly into vapor without first going through the liquid water phase – a
March 19, 2024
Freezer Burn: What It Is, Food Safety, and Tips for Prevention
Freezer burn is the dehydration of food that results from moisture loss during freezing. It can happen to any food that’s been frozen for a long time. As dehydration occurs, oxygen moves in to take its place....It’s more likely to occur among foods that:...- are not wrapped well- experience fluctuating temperature (such as frequent or prolonged opening of the freezer door)- are kept in the freezer longer- contain more water...All foods contain wa
November 3, 2025
How to prevent freezer burn and what to do with food affected by it - The Washington Post
“The moisture-carrying capacity of air decreases with temperature,” said Rohan Tikekar, an associate professor of food science at the University of Maryland. In other words, cold air is drier than warm air, while food contains a relatively large amount of water. Because of this differential in moisture content, the cold air in your freezer wants to suck the water out of the food stored within it, which happens through a process called sublimation
January 12, 2024
What Is Freezer Burn? Ask Paul | America's Test Kitchen
What Causes Freezer Burn?...Freezer burn is the general term for the unpleasant flavor, texture, and appearance that food can develop when frozen....Inside a freezer, the air is very dry, because cold air can’t hold as much moisture as warmer air. The dryness of the air means that water evaporates more readily. This is the principle behind freeze-drying, and it’s the reason that, if you leave them untouched in the freezer too long, ice cubes s
April 12, 2023
Which? scientist explains what freezer burn is and how to prevent it - Which?
Freezer burn occurs when meat is exposed to the harsh cold air of the freezer for an extended period, developing a greyish-brown discolouration and a harsh, leathery texture on the surface....Monika explains: 'It's caused by the loss of water through a process known as sublimation, where ice crystals turn directly from a solid into a gas without melting first. As this moisture escapes, it leaves behind empty spaces in the meat, which are quickly
March 17, 2026
Freezer burn
Freezer burn is a condition that occurs when frozen food has been damaged by dehydration and oxidation due to air reaching the food. [1] It is generally caused by food not being securely wrapped in air-tight packaging....Freezer burn appears as grayish-brown leathery spots on frozen food and occurs when air reaches the food's surface and dries the product. Color changes result from chemical changes in the food's pigment. Freezer burn does not mak
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How Does the Freezer Burn Our Food?
ABSTRACT:Freezer burn is a common problem that significantly affects the color, texture, and flavor of frozen foods. Food science students should be able to clearly explain the causes and consequences of freezer burn. However, it is difficult to find a modern, detailed, accurate, yet concise, explanation of the mechanism and factors influencing the rate of freezer burn, suitable for classroom use. Thus, the purpose of this article is to provi
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Understanding the Process of Freezing
Rapid freezing improves the quality of the food. The faster the food freezes, the smaller the crystals that form. Small crystals do less damage to cell walls. Slow freezing...large ice crystals that punch through cell membranes....a result, when foods with large ice crystals thaw, there is more dripping and loss of liquid. Small crystals are unstable and, over time, grow to form larger crystals. This is especially noticeable in the freeze-thaw cy
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