The draft 2003 edition of the Oxford English Dictionary lists the earliest known usage of the concept as being in L. Chatterton's book Modern Cookery published in 1943: "Afternoon tea scones… Time: 20 minutes. Temperature: Gas, Regulo Mark 7". "Regulo" was a type of gas regulator used by a manufacturer of cookers; however, the scale has now become universal, and the word Regulo is rarely used.
The term "gas mark" was a subject of the joint BBC/OED TV series Balderdash & Piffle, in May 2005, which sought to establish the history of the term. The earliest printed evidence of use of "gas mark" (with no other terms between the two words) appears to date from 1958. However, the manufacturers of the "New World" gas ranges in the mid-1930s gave away recipe books for use with their cooker, and the "Regulo" was the gas regulator. The book has no reference to degrees, either in Fahrenheit or (as then) Centigrade. All dishes to be cooked are noted to be at "Regulo Mark X".
(Appropriate references can found in the section above.) Gas mark 1 is 275° Fahrenheit (135° Celsius). Oven temperatures increase by 25°F (13.9°C) each time the gas mark increases by 1. Below gas mark 1 the scale markings halve at each step, each representing a decrease of 25°F.
|1⁄4||225°||107°||Very Slow/Very Low|
|1⁄2||250°||121°||Very Slow/Very Low|
Different manufacturers and oven types do vary, so this table cannot be relied upon; instead, cooks should refer to the cooker instruction book for the oven type used, or calibrate the scale using an oven thermometer.
Other cooking temperature scales
French ovens and recipes often use a scale more closely related to the Celsius temperature: "Thermostat" (abbreviated "Th"), where Thermostat 1 equals 30 °C for conventional ovens, increasing by 30 °C for each whole number along the scale.
In Germany, "Stufe" (the German word for "step") is used for gas cooking temperatures. Gas ovens are commonly marked in steps from 1 to 8, corresponding to:
|Approx. Temp.||150 °C||160 °C||180 °C||200 °C||220 °C||240 °C||260 °C||280 °C|
Other ovens may be marked on a scale of 1-7, where Stufe ½ is about 125 °C in a conventional oven, Stufe 1 is about 150 °C, increasing by 25 °C for each subsequent step, up to Stufe 7 at 300 °C.
- Extract revised for OED Online: 7. gas mark n.
- "Oven Temperatures". Practically Edible. 5 October 2007. Retrieved 20 June 2010.
- "Temperatur-Angaben". GuteKueche. Retrieved 11 Feb 2012.