Drying oil

<p>A drying oil is an <a href="/facts/Oil/fsgX2IRM">oil</a> that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components <a href="/facts/Cross-link/zeQ9hEAA">crosslink</a> (and hence <a href="/facts/Polymerize/1hmBz7Ur">polymerize</a>) by the action of <a href="/facts/Oxygen/acyn6o8r">oxygen</a> (not through the <a href="/facts/Evaporation/tgvIlJys">evaporation</a> of water or other <a href="/facts/Solvent/LoMPMz8S">solvents</a>). Drying oils are a key component of <a href="/facts/Oil_paint/YMgKMEaU">oil paint</a> and some <a href="/facts/Varnish/sK905uXj">varnishes</a>. Some commonly used drying oils include <a href="/facts/Linseed_oil/v0XdLFcr">linseed oil</a>, <a href="/facts/Tung_oil/mqz1xtkf">tung oil</a>, <a href="/facts/Poppyseed_oil/TUDMQGrW">poppy seed oil</a>, <a href="/facts/Perilla_oil/5X9kqoQd">perilla oil</a>, <a href="/facts/Castor_oil/tag0x1BT">castor oil</a> and <a href="/facts/Walnut_oil/RoG9Inqy">walnut oil</a>.  The use of natural drying oils has declined over the past several decades, as they have been replaced by <a href="/facts/Alkyd/KNUpJgKB">alkyd</a> resins and other binders.
</p><p>Since oxidation is the key to curing these oils, those that are susceptible to chemical drying are often unsuitable for cooking and are also highly susceptible to becoming <a href="/facts/Rancidification/nzHTQkc4">rancid</a> through autoxidation, the process by which fatty foods develop off-flavors. Rags, cloth, and paper saturated with drying oils may <a href="/facts/Spontaneous_combustion/ULScfFt1">spontaneously combust</a> (ignite) after a few hours as heat is released during the oxidation process.
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Drying oil open-in-new

Drying oil