page_title: Dunking (biscuit)
section_title: Science
hierarchical_section_title: Dunking (biscuit) / Science
caption_attribution_description: English: Dunking an oreo cookie.
context_page_description: To dunk or to dip a biscuit or some other food, usually baked goods, means to submerge it into a drink, especially tea, coffee, or milk. Dunking releases more flavour from confections by dissolving the sugars, while also softening their texture. Dunking can be used to melt chocolate on biscuits to create a richer flavour.
  Dunking is a popular way of enjoying biscuits in many countries. A popular form of dunking in Australia is the "Tim Tam Slam", also known as 'tea sucking'.
  The physics of dunking is driven by the porosity of the biscuit and the surface tension of the beverage. A biscuit is porous and, when dunked, capillary action draws the liquid into the interstices between the crumbs.
  Dunking is first reported with ancient Romans softening their hard unleavened wafers in wine. Modern day dunking has its roots in naval history when, in the 16th century, biscuits known as "hard tack" were on board Royal Navy ships, which were so hard that the British sailors would dunk them in beer in order to soften them up. The most popular biscuit to dunk in tea in the United Kingdom is McVitie's chocolate digestive.
context_section_description: Physicist Len Fisher of the University of Bristol presented some light-hearted discussion of dunking on "National Biscuit Dunking Day" in the UK, as part of an attempt to make physics accessible. Fisher appeared to be somewhat taken aback by the large amount of media attention, ascribing it to a "hunger for accessible science".  Fisher also described his astonishment at journalists' interest in one equation used in the field: Washburn's equation, which describes capillary flow in porous materials.  Writing in Nature, he says "the equation was published in almost every major UK newspaper.  The journalists who published it took great care to get it right, some telephoning several times to check".
  In 2012, Michelin starred English restaurateur Heston Blumenthal researched the effect of dunking chocolate biscuits, and concluded that it improved the biscuit's taste. "If you have chocolate on one side, if it melts a bit, you get a velvety smooth texture and then the delicious flavour as a result."
caption: An Oreo cookie dunked into milk.
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