To convert a Fahrenheit temperature to Celsius, subtract 32, then multiply the result by 5 and divide by 9. On gas ovens with numbered settings, the numbers represent ranges: setting 1 is around 140°C / 285°F, setting 4 around 180°C / 355°F, and setting 7 around 220°C / 430°F. If you use a convection oven, set the temperature 10–20°C / 18–36°F lower than the converted value.
The formula is one line: to find the Celsius temperature, subtract 32 from the Fahrenheit value, multiply by 5, then divide by 9. Here is the calculation for 350°F: 350 minus 32 equals 318; 318 multiplied by 5 and divided by 9 is about 177, which is rounded in the kitchen to either 175°C / 345°F or 180°C / 355°F. Oven displays already use either a 5°C / 9°F change or a 10°C / 18°F change, so this rounding does not cause a problem. To convert in the other direction, multiply Celsius by 9, divide by 5, and add 32.
In practice, memorizing a few values is enough for most recipes. 300°F is about 150°C, 325°F about 160°C, 350°F about 175–180°C, 375°F about 190°C, 400°F about 200°C, 425°F about 220°C, and 450°F about 230°C. The intervals in this sequence are 25°F, or roughly 15°C. Recipes from other countries usually use these increments; if you see a value in between, use the formula. Meat’s internal temperatures are converted using the same formula; 165°F corresponds to 74°C, the temperature used for poultry.
Gas ovens use a different scale, with numbered settings instead of temperature units on the dial. Their approximate equivalents are: setting 1, 140°C / 285°F; setting 2, 150°C / 300°F; setting 3, 160°C / 320°F; setting 4, 180°C / 355°F; setting 5, 190°C / 375°F; setting 6, 200°C / 390°F; setting 7, 220°C / 430°F; and setting 8, 230°C / 445°F. These equivalents vary by a few °C from brand to brand, so treat the settings as ranges, not exact numbers, and account for how your oven performs.
After converting, you may need to make two more adjustments. First is the fan: if the recipe is written for a conventional oven and you plan to use convection, set the temperature 10–20°C / 18–36°F lower than the converted value. Second is the oven’s own variation; most ovens differ from the temperature shown on the display, and you can see this difference only with a thermometer placed inside the oven. Even if the converted number is correct, the result can still be off if the oven does not hold that temperature. An oven thermometer is also the only way to see this variation in a gas oven. Once you learn how your oven behaves, adjust the conversion for that oven.
Other measurements in the recipe may need to be converted too. Pan sizes given in inches are converted to centimeters; a 9-inch pan is about 23 centimeters, and an 8-inch pan about 20 centimeters. The cooking time usually stays the same when you convert the temperature, because you already check for signs of doneness. When trying a recipe for the first time, check the oven more often toward the end of the stated cooking time, and judge doneness by the food’s condition rather than the number on the display. If you write the converted values in the margin of the recipe once, you will not have to calculate them again the second time you make it.
Comments (2)
Üç yüz elli Fahrenhayt yüz yetmiş beş, bunu ezberleyince yabancı tariflerin yarısı çözülüyor. Ben eskiden telefondan hesap makinesi açıp çeviriyordum ve bazen otuz ikiyi çıkarmayı unutup yüz doksan yedi gibi tuhaf sayılar buluyordum.