Temperature conversion?

[lakelady1]

The eldest daughter called in a tizzy. She and her husband have just moved to England and she informed me her new oven was "crazy". She has always cooked frozen pizza at 450 degrees; and the pizza she purchased at the military base had all the usual American instruction, but this "stupid oven" only went up to 250 degrees.

Well, when I finished laughing, I explained to her that the oven was undoubtedly in Celcius (Centigrade) while the "American" plan is Fahrenheit. But, while I could give her the complicated algebraic equation for conversion (let's see, you have 100 degrees between freezing at 0 and boiling at 100 and 180 degrees between freezing at 32 at boiling at 212, so 450 in F would be ?? in C), she was neither happy nor convinced.

So, is there an easy conversion table? Or a place to get one??? Or should she just double or halve everything (depending upon which way she is going) and hope for the best? This is why I was not a math or science major . . . nor was she!

[MKSquared]

Before you get in a tizzy, don't worry. :) It looks hard, but it's not.

In the formulas below, / means to divide, * means to multiply, - means subtract, + means to add and = is equal. Tc = temperature in degrees Celsius, Tf = temperature in degrees Fahrenheit

To convert a Fahrenheit temperature into Celsius:
Tc = (5/9)*(Tf-32)

For example, to convert a Fahrenheit temperature of 98.6 degrees into degrees Celsius first subtract 32 from the Fahrenheit temperature to get 66.6. Then you multiply 66.6 by five-ninths to get 37 degrees Celsius.

To kind of do it in your head, imagine subtracting about 32 (make it an easy number close to 32 to subtract) ... then think of dividing THAT number in half. The real answer will be slightly higher.)

To convert a Celsius temperature into degrees Fahrenheit:
Tf = ((9/5)*Tc)+32

For example, to convert a Celsius temperature of 100 degrees into degrees Fahrenheit, first multiply the Celsius temperature reading by nine-fifths to get 180. Then add 32 to 180 and get 212 degrees Fahrenheit.


.... so, to get 450 degrees F into centigrade, you'd:
tC = (5/9)(450-32)
tC = (5/9) (418)
(now, just basically consider that you're multiplying by almost 1/2. if your answer isn't close to reasonable, check again.:) )
tC = 5*418/9
tC = 46.4 *5
tC = 232.2

If you tried it in your head, you'd have
1) subtract about 32 .... 450-30 = 420
2) divide into half ... 420/2 = 210
3) real answer is higher by less than 10% of 420 ... (42)

It's not dead on, but it gives an idea, anyway. :)

[Grace]

Here's the conversion chart from one of Alton Brown's books (gas mark is for some European ovens where they just give single digit numbers from 1/2 to 9):


250-275F = 130-140 C = 1/2 - 1 Gas mark
300F = 150C = 2 Gas
325F = 170C = 3 Gas
350F = 180C = 4 Gas
375-400F = 190-200C = 5-6 Gas
425-450F = 220-230C = 7-8 Gas
475F = 250C = 9 Gas


Hope that helps!!

[kvieceli]

I just moved to England, too ... I roughly estimate Farenheit to Celsius at about half ... so if an American pizza should cook at 350, here it would be about 175. I'd suggest two things - Junior League puts out a great handbook on Living in London (see their website to order) and just tell her to get an oven thermometer ... that shows both C & F. Also - get a couple of measuring cups - the clear kind, that show all different measurements. Does that make sense - I think OXO makes some large 2 cup + capacity that you that have a variety of different measurement variations on them. Tell her good luck :)

[kvieceli]

P.S. Also wanted to note that my oven here is a convection oven - so it cooks differently from the conventional ovens in the U.S., tell her to check that for cooking times as well. If she knows the make of the oven, she can call the company and they will send directions on the particular model she has.