When your food goes from frozen to fossilised. Should you risk it? <\/p>
You may have noticed that ice cubes kept in the freezer for a long time have a tendency to shrink as water is lost.\u00a0This is because in\u00a0dry\u00a0freezer air, ice can transform directly into water vapour without first becoming a liquid, in a process known as sublimation<\/a>.<\/p>\n Ice sublimates in an effort to equilibrate with the vapour pressure of air in the freezer. The water\u00a0lost from\u00a0food items during sublimation is redeposited on the food\u2019s surface,\u00a0and on refrigeration cools\u00a0as ice crystals.<\/p>\n The moisture loss means that fruit and vegetables can become shrivelled and dry,\u00a0while meats can develop a leathery texture and dark spots. The dehydration creates pockets in the food which are then open to the air, accelerating oxidation. In fatty foods, this oxidation can cause unpleasant flavours<\/a>.\u00a0Food with freezer burn is unpalatable, but safe to eat.<\/p>\n All foods are susceptible to freezer burn,\u00a0but those with higher moisture levels will develop it more rapidly. To reduce the likelihood of freezer burn, you can vacuum seal food<\/a> to remove the air that drives the sublimation process. Or if you don\u2019t have a vacuum sealer, wrap the products as tightly as possible and stack them to limit the exposed surface area.<\/p>\n Finally, make sure you regularly rotate your freezer stock so that items are not left languishing for long periods. Some people suggest filling containers with water and leaving them open in the freezer to help maintain humidity and reduce sublimation. Self-defrosting freezers can cause more burn. They regularly melt the ice layer on refrigeration coils, but this keeps the vapour pressure low, driving sublimation.<\/p>\n Freezer burn is similar to the freeze-drying<\/a> process that food companies use to create long-life\u00a0foods\u00a0for astronauts<\/a> and mountaineers, as well as instant coffee and some dried fruits. The industrial process involves freezing foods, dropping the pressure using a vacuum, then\u00a0removing the ice.<\/p>\n Read more:<\/strong><\/p>\n Asked by: Aiden Chambers, London<\/strong><\/p>\n To submit your questions email us at questions@sciencefocus.com (don\u2019t forget to include your name and location)<\/em><\/p> <\/body><\/html>\n When your food goes from frozen to fossilised. Should you risk it? <\/p>\n","protected":false},"author":24,"featured_media":26352,"template":"","categories":[30],"acf":{"readingTimeMinutes":"2"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/freezer-burn-why-it-happens-and-how-you-can-prevent-it.jpg",1200,511,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/freezer-burn-why-it-happens-and-how-you-can-prevent-it-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/freezer-burn-why-it-happens-and-how-you-can-prevent-it-300x128.jpg",300,128,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/freezer-burn-why-it-happens-and-how-you-can-prevent-it-768x327.jpg",768,327,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/freezer-burn-why-it-happens-and-how-you-can-prevent-it-1024x436.jpg",800,341,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/freezer-burn-why-it-happens-and-how-you-can-prevent-it.jpg",1200,511,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/freezer-burn-why-it-happens-and-how-you-can-prevent-it.jpg",1200,511,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"When your food goes from frozen to fossilised. Should you risk it?","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/rss_feed\/26351"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/media\/26352"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/media?parent=26351"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/categories?post=26351"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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