Editing Teaspoon (section)

== Unit of measure {{anchor |unit}}==
{{Infobox unit
| bgcolor      =
| name         = teaspoon
| image        = 4MeasuringSpoons.jpg
| caption      = Measuring spoons, with the second largest one representing the volume of a teaspoon.
| standard     = [[Imperial units]], [[US customary units]]
| quantity     = Volume
| symbol       = tsp
| symbol2      =
| namedafter   =
| extralabel   =
| extradata    =
| units_imp1   = SI units
| inunits_imp1 = 3.552 mL
| units_imp2   = US customary units
| inunits_imp2 = 0.721 US tsp
| units_us1    = SI units
| inunits_us1  = 4.929 mL
| units_us2    = Imperial units
| inunits_us2  = 1.388 imp tsp
}}
In some countries, a teaspoon (occasionally '''teaspoonful''') is a [[Cooking measures|cooking measure]] of [[volume]], especially widely used in cooking recipes and pharmaceutic medical prescriptions. In English it is abbreviated as ''tsp.'' or, less often, as ''t.'', ''ts.'', or ''tspn.''. The abbreviation is never capitalized because a capital letter is customarily reserved for the larger [[tablespoon]] ("Tbsp.", "T.", "Tbls.", or "Tb.").<ref>In German and Dutch, teaspoon is abbreviated ''TL'', for ''Teelöffel'' and ''Theelepel'' respectively.</ref>

A small scale study in Greece found that household teaspoons are a poor approximation of the standard tsp measure. The study investigated the accuracy of teaspoons as a measuring tool for liquid medicine. They surveyed 71 teaspoons from 25 houses and found that the volume varied between {{cvt|2.5|and|7.3|mL}}.{{sfn|Falagas|Vouloumanou|Plessa|Peppas|2010|p=1185}}

===Metric teaspoon===
The metric teaspoon as a unit of culinary measure is 5&nbsp;mL,<ref name="us">21 [[Code of Federal Regulations|CFR (Code of Federal Regulations)]] [http://edocket.access.gpo.gov/cfr_2004/aprqtr/21cfr101.9.htm 101.9(b)(5)(viii)]</ref> equal to {{Val|5|ul=cm3}}, {{frac|1|3}} international metric tablespoon, or {{frac|1|4}} Australian metric tablespoon.<ref>{{Cite web|url=http://www.airo2012.it/convert-cup-tablespoon/|title=How to Convert Cup to Tablespoon?|date=8 June 2016|website=Airo|access-date=16 June 2016|archive-date=17 June 2016|archive-url=https://web.archive.org/web/20160617202706/http://www.airo2012.it/convert-cup-tablespoon/|url-status=dead}}</ref>

{|
|-
|1 metric teaspoon&nbsp;
||=
|align=right|5||mL
|-
|||=
|align=right|{{sfrac|1|3}}||[[Tablespoon#International metric|international metric tablespoon]]
|-
|||=
|align=right|{{sfrac|1|4}}||[[Tablespoon#Australian metric|Australian metric tablespoon]]
|-
|||=
|align=right|{{sfrac|1|2}}||[[Dessert spoon#Culinary measure|metric dessert spoon]]
|-
|||≈
|align=right|1.41||[[Dram (unit)#Unit of volume|British imperial fluid drachms]]
|-
|||≈
|align=right|0.18||[[Fluid ounce|British imperial fluid ounce]]
|-
|||≈
|align=right|0.35||[[Tablespoon#United Kingdom|UK tablespoon]]
|-
|||≈
|align=right|0.7||[[Dessert spoon#Culinary measure|UK dessert spoon]]
|-
|||≈
|align=right|1.41||[[Teaspoon#British culinary measurement unit|UK teaspoons]]
|-
|||≈
|align=right|2.81||[[Salt spoon|UK salt spoons]]
|-
|||≈
|align=right|5.63||[[Pinch (unit)|UK pinches]] (solids only)
|-
|||≈
|align=right|84.47||[[Drop (unit)|UK drops]] (liquids only)
|-
|||≈
|align=right|1.35||[[Dram (unit)#Unit of volume|US customary fluid drams]]
|-
|||≈
|align=right|0.17||[[Fluid ounce|US customary fluid ounce]]
|-
|||≈
|align=right|0.34||[[Tablespoon#United States|US customary tablespoon]]
|-
|||≈
|align=right|0.51||[[Dessert spoon#Culinary measure|US customary dessert spoon]]
|-
|||≈
|align=right|1.01||[[Teaspoon#United States customary unit|US customary teaspoons]]
|-
|||≈
|align=right|2.03||US customary coffee spoons
|-
|||≈
|align=right|4.06||[[Salt spoon|US customary salt spoons]]
|-
|||≈
|align=right|8.11||[[Cooking weights and measures#United States measures|US customary dashes]] (solids only)
|-
|||≈
|align=right|16.23||[[Pinch (unit)|US customary pinches]] (solids only)
|-
|||≈
|align=right|32.46||[[Cooking weights and measures#United States measures|US customary smidgens]] (solids only)
|-
|||≈
|align=right|97.38||[[Drop (unit)|US customary drops]] (liquids only)
|}

===United States customary unit===
{{hatnote|See [[United States customary units]] for relative volumes of these and other measures.}}
As a unit of culinary measure, one teaspoon in the United States is {{frac|1|3}} [[tablespoon]], exactly {{val|4.92892159375}}&nbsp;[[Litre#SI prefixes applied to the litre|millilitres]] (mL), 1{{frac|1|3}} [[Dram (unit)#Unit of volume|US customary fluid drams]], {{frac|1|6}} [[Fluid ounce|US customary fl. oz]], {{frac|1|48}} [[Cup (volume)|US cup]], {{frac|1|768}} US liquid [[gallon]], or {{frac|77|256}}&nbsp;(0.30078125)&nbsp;[[cubic inch]]es.

{|
|-
|1 US customary teaspoon&nbsp;
||=
|align=right|1{{sfrac|1|3}}||US customary fluid drams
|-
|||=
|align=right|{{sfrac|1|6}}||US customary fluid ounce
|-
|||=
|align=right|{{sfrac|1|3}}||[[Tablespoon#United States|US customary tablespoon]]
|-
|||=
|align=right|{{sfrac|1|2}}||[[Dessert spoon#Culinary measure|US customary dessert spoon]]
|-
|||=
|align=right|2||US customary coffee spoons
|-
|||=
|align=right|4||[[Salt spoon|US customary salt spoons]]
|-
|||=
|align=right|8||[[Cooking_weights_and_measures#United_States_measures|US customary dashes]] (solids only)
|-
|||=
|align=right|16||[[Pinch (unit)|US customary pinches]] (solids only)
|-
|||=
|align=right|32||[[Cooking weights and measures#United States measures|US customary smidgens]] (solids only)
|-
|||=
|align=right|96||[[Drop (unit)|US customary drops]] (liquids only)
|-
|||≈
|align=right|1.39||[[Dram (unit)#Unit of volume|British imperial fluid drachms]]
|-
|||≈
|align=right|0.17||[[Fluid ounce|British imperial fluid ounce]]
|-
|||≈
|align=right|0.35||[[Tablespoon#United Kingdom|UK tablespoon]]
|-
|||≈
|align=right|0.69||[[Dessert spoon#Culinary measure|UK dessert spoons]]
|-
|||≈
|align=right|1.39||[[Teaspoon#British culinary measurement unit|UK teaspoons]]
|-
|||≈
|align=right|2.78||[[Salt spoon|UK salt spoons]]
|-
|||≈
|align=right|5.55||[[Pinch (unit)|UK pinches]] (solid only)
|-
|||≈
|align=right|83.27||[[Drop (unit)|UK drops]] (liquids only)
|-
|||=
|align=right|4.92892159375||[[Litre#SI prefixes applied to the litre|millilitres]]
|-
|||≈
|align=right|0.33||[[Tablespoon#International metric|international metric tablespoon]]
|-
|||≈
|align=right|0.25||[[Tablespoon#Australian metric|Australian metric tablespoon]]
|-
|||≈
|align=right|0.49||[[Dessert spoon#Culinary measure|metric dessert spoon]]
|-
|||≈
|align=right|0.99||[[Teaspoon#Metric teaspoon|metric teaspoon]]
|}

For nutritional labeling and medicine in the US, the teaspoon is defined the same as a metric teaspoon{{mdash}}precisely 5&nbsp;millilitres (mL).<ref>21CFR101.9(b)(5)(viii) [http://edocket.access.gpo.gov/cfr_2004/aprqtr/21cfr101.9.htm 2 1CFR101.9]</ref>

===British culinary measurement unit===
Traditionally, in the United Kingdom, 1 teaspoon is 1 [[Dram (unit)#Unit of volume|British imperial fluid drachm]]<ref>[https://www.victorianschool.co.uk/ebooks/enquire%20within/10766-h/10766-h.htm#p665 Paragraph 665], page 119, ''Enquire Within Upon Everything'' (1894)</ref> ({{frac|1|8}} [[Fluid ounce|British imperial fluid ounce]]).  1 UK teaspoon is the equivalence of {{frac|1|4}} [[Tablespoon#United Kingdom|UK tablespoon]], {{frac|1|2}} [[Dessert spoon#Culinary measure|UK dessert spoon]], or 2 [[Salt spoon|UK salt spoons]].

{|
|-
|1 UK teaspoon&nbsp;
||=
|align=right|1||British imperial fluid drachm
|-
|||=
|align=right|{{frac|1|4}}||UK tablespoon
|-
|||=
|align=right|{{frac|1|2}}||UK dessert spoon
|-
|||=
|align=right|2||UK salt spoons
|-
|||=
|align=right|4||[[Pinch (unit)|UK pinches]] (solids only)
|-
|||=
|align=right|60||[[Drop (unit)|UK drops]] (liquids only)
|-
|||=
|align=right|{{frac|1|8}}||British imperial fluid ounce
|-
|||≈
|align=right|0.96||[[Dram (unit)#Unit of volume|US customary fluid dram]]
|-
|||≈
|align=right|0.12||[[Fluid ounce|US customary fluid ounce]]
|-
|||≈
|align=right|0.24||[[Tablespoon#United States|US customary tablespoon]]
|-
|||≈
|align=right|0.36||[[Dessert spoon#Culinary measure|US customary dessert spoon]]
|-
|||≈
|align=right|0.72||US customary teaspoon
|-
|||≈
|align=right|1.44||US customary coffee spoons
|-
|||≈
|align=right|2.88||[[Salt spoon|US customary salt spoons]]
|-
|||≈
|align=right|5.76||[[Cooking weights and measures#United States measures|US customary dashes]] (solids only)
|-
|||≈
|align=right|11.53||[[Pinch (unit)|US customary pinches]] (solids only)
|-
|||≈
|align=right|23.06||[[Cooking weights and measures#United States measures|US customary smidgens]] (solids only)
|-
|||≈
|align=right|69.17||[[Drop (unit)|US customary drops]] (liquids only)
|-
|||≈
|align=right|3.55||[[Litre#SI prefixes applied to the litre|millilitres]]
|-
|||≈
|align=right|0.24||[[Tablespoon#International metric|international metric tablespoon]]
|-
|||≈
|align=right|0.18||[[Tablespoon#Australian metric|Australian metric tablespoon]]
|-
|||≈
|align=right|0.36||[[Dessert spoon#Culinary measure|metric dessert spoon]]
|-
|||≈
|align=right|0.71||[[Teaspoon#Metric teaspoon|metric teaspoon]]
|}

===Dry ingredients===
For dry granular or powdered ingredients (e.g., [[salt]], [[flour]], [[spices]], and especially beverages involving [[tea]] and [[sugar]]),<ref>{{cite book |last=Souter |first=Keith |author-link= |date=2013 |title=The Tea Cyclopedia |url=https://books.google.com/books?id=yluCDwAAQBAJ&pg=PT92 |publisher=Skyhorse Publishing |page= 92|isbn=9781628735482}}</ref> a recipe may call for  the spoon to be filled in a certain way that changes the volume of the ingredient. As with much of cooking, these measures are by their nature inexact. This can be exacerbated here by failing to use a real teaspoon: a teaspoon's greater area supports considerably more to be heaped above it than a deeper hemispherical measuring spoon, so if using a measuring spoon, one will typically use less than called for by the recipe. The definitions of "spoonful" vary, in particular, in a typical American recipe a "spoon" without clarification stands for a "level" spoon (the one with no ingredient showing above the rim of the spoon bowl), while a British cookbook would mean a "round" or "heaped" spoon, with the ingredient peaking above the rim:{{sfn|Grigson|2007|p=xviii}} 
* A ''scant'' teaspoon is one which has been filled to slightly less than level.{{sfn|Baggett|2012}}
* A ''level'' teaspoon, which is the default ''teaspoon'' if no adjective is given, refers to an approximately leveled filling of the spoon, producing the same volume as for liquids. The excess of ingredient can be scraped off by a knife.{{sfn|BBC|1945}}
* A ''rounded'' teaspoon is roughly symmetrical with as much ingredient above the rim as is in the spoon below the rim, giving a measure roughly equivalent to two level teaspoons.{{sfn|BBC|1945}}
* A ''heaping'' (North American English) or ''heaped'' (UK English) teaspoon is a larger inexact measure consisting of the amount obtained by scooping the dry ingredient up as high as possible to balance on a spoon. This quantity can vary considerably, up to 5 amounts of ingredient in the level spoon.{{sfn|BBC|1945}} Many cookbooks treat heaped and rounded spoons interchangeably.{{sfn|Collister|2012}}{{sfn|Henderson|Gellatly|2008}}
Lincoln used the spoon measure without adjectives to define either a rounded one (for flour and sugar) or a level one (for salt and spices).{{sfn|Lincoln|1903|p=24}}

=== Apothecary ===
{{See also|Apothecaries' system}}
As an unofficial but once widely used unit of [[Apothecaries' system|apothecaries' measure]], the teaspoon is equal to 1&nbsp;fluid dram (or drachm) and thus {{frac|4}} of a tablespoon or {{frac|8}} of a fluid ounce.<ref name="Ludy1907">{{cite book|author=Robert Borneman Ludy|title=Answers to questions prescribed by pharmaceutical state boards|url=https://books.google.com/books?id=xMwRAAAAYAAJ&pg=PA125|year=1907|publisher=J.J. McVey|page=125}}</ref><ref name="Collins1803">{{cite book|author=Dr. Collins|title=Practical rules for the management and medical treatment of Negro slaves in the sugar colonies|url=https://books.google.com/books?id=clsSAAAAIAAJ&pg=PA465|year=1803|publisher=Printed by J. Barfield, for Vernor and Hood|page=465}}</ref> The apothecaries' teaspoon was formally known by the Latin ''cochleare minus'' (''cochl. min.'') to distinguish it from the tablespoon or ''cochleare majus'' (''cochl. maj.'').<ref name="encyclopedia1884">{{cite book|editor=Alexander Whitelaw|editor-link=Alexander Whitelaw (editor)|title=The popular encyclopedia; or, 'Conversations Lexicon'|url=https://books.google.com/books?id=68LpFwitupEC&pg=PA11|year=1884|page=11}}</ref><ref name="Milne-EdwardsVavasseur1831">{{cite book|author1=Henri Milne-Edwards|author2=Pierre Henri L.D. Vavasseur|title=A manual of materia medica and pharmacy, from the Fr. of H.M. Edwards and P. Vavasseur, corrected by J. Davies|url=https://books.google.com/books?id=M75Q-5iRUjwC&pg=PR12|year=1831|page=12}}</ref>

When tea-drinking was first introduced to England circa 1660, tea was rare and expensive, as a consequence of which teacups and teaspoons were smaller than today. This situation persisted until 1784, when the [[Commutation Act]] reduced the tax on tea from 119% to 12.5%.<ref>Tea.co.uk. (2020). UK Tea & Infusions Association{{Snd}} Illicit Tea Trades. [online] Available at: https://www.tea.co.uk/tea-smuggling [Accessed 1 February 2020].</ref> As the price of tea declined, the size of teacups and teaspoons increased. By the 1850s, the teaspoon as a unit of culinary measure had increased to <small>{{frac|3}}</small> of a tablespoon, but the apothecary unit of measure remained the same.<ref name="Griffith1859">{{cite book |author=Robert Eglesfeld Griffith |title=A universal formulary: containing the methods of preparing and administering officinal and other medicines. The whole adapted to physicians and pharmaceutists |url=https://books.google.com/books?id=h-4jAQAAMAAJ&pg=PA25|year=1859 |publisher=H.C. Lea |page=25}}</ref> Nevertheless, the teaspoon, usually under its Latin name, continued to be used in apothecaries' measures for several more decades, with the original definition of one fluid dram.