Gas Mark

The Gas Mark is a temperature scale used on gas ovens and cookers in the United Kingdom, Ireland and some Commonwealth of Nations countries.

History

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 (as then) or Centigrade. All dishes to be cooked are noted to be at "Regulo Mark X".

Conversion

To convert gas mark to Celsius simply get your gas mark(G) multiply it by 14 then add 121 and you get the Celsius(D) (G × 14) + 121 = D or the other way round (D - 121) / 14 = G (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.

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 based on the Fahrenheit scale: "Thermostat" (abbreviated "Th"), where Thermostat 1 equals 100 °F for conventional ovens, increasing by 50 °F for each whole number along the scale.

For convenience, you can get an approximate temperature in degrees Celsius (°C) by multiplying the Th value by 30 °C.

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:

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.

References