I always knew that the UK gallon and the US gallon were different. What I didn’t know – and should have – is that the US cup vs. the Canadian cup are different. Oh, sure, Canadians were an English colony, so of course our gallons were UK gallons, not US.
And then I recently learned that a Sri Lankan cup is not 8 ounces, but 6. Sometimes. And I’ve also seen measuring cups here say that one cup is equal to 160 ml.
And then there’s the metric cup – what the heck is up with that?
- 1 cup (Canadian and UK) = 8 fluid ounces (UK) = 227.3 ml
- 1 cup (US) = 8 fluid ounces (US) = 236.6 ml
- 1 cup (Sri Lankan) = 6 fluid ounces (UK) = 170 ml or 160 ml, although I’ve also seen it as low as 140 ml.
- 1 cup (metric) = 250 ml
When you’re looking at a recipe, do you always know where the person who wrote it is from? Do you know which conventions they go by? If it was published in a cookbook (for example), which country was it published in? There is a huge difference between 160 ml and 250 ml!
At least when you’re dealing with liquid measurements, unless you’re looking at Sri Lankan recipes, the difference between 225 ml and 237 ml isn’t very much, so with most recipes, you can pretty much write it off and go with whichever you prefer. Unless you’re the anal type, like me. Or it’s a recipe that requires on a specific quantity due to a required chemical reaction – i.e., baking.
But when you’re dealing with dry ingredients, like flour or brown sugar, for example, it gets a lot more complicated. Did the person who created the recipe use packed brown sugar or loose? Is that sifted flour (fluffed up) or straight out of the bag where it’s been sitting so long it’s now compressed? How are you scooping your ingredients?
There’s this little blurb at SourdoughHome that talks about the differences in how people measure flour:
In a UseNet baking newsgroup a good number of people with scales measured the weight of a cup of flour. And a cup of flour ranged from less than 100 to more than 200 grams. Worse, the cup to cup variation was as much as 25% for the scoopers. The sifters were within 10 to 12% from cup to cup, which is better but not all that thrilling.
Plus there’s the whole ounces as in fluid or ounces as in weight and the confusion that can arise there…
I’ve found a site that offers conversions of common ingredients (it doesn’t have everything, of course – no coconut milk) from a volume measurement to a weight measurement. There’s another one here. As well, there’s NutritionData which doesn’t have a volume to weight converter, but does have volume and weight measurements for common ingredients on the individual ingredients page. Its list of ingredients is huge and can even tell me that 1 cup of shredded coconut (raw) is 80 grams. The first two couldn’t tell me that, so this is obviously the place to go for the more esoteric ingredients. Esoteric to average Americans, anyway. 🙂 More than that, though, NutritionData has, you guessed it, nutritional data on foods as well, and it’s quite interesting. More than just the standard info.
I don’t know which is more accurate – I’d have to do some measuring and weighing and comparing, but since I have a crap scale, I can’t get decently accurate myself anyway. Yet. A better scale is on the list. 🙂
Then there’s the argument that hydration levels of flours vary, so weighing isn’t entirely accurate either. Good point, but weighing is still a better starting point than measuring by volume, and I have no way to measure hydration levels of flour anyway.
All of which is the long-winded reasoning behind why I’ve switched, as much as is reasonable, to weighted measurements in recipes using grams. Grams since I’m a metric girl anyway, but beyond that, grams are easier to work with in scaling recipes up or down.
As a side note, I weighed a cup of flour. I got anywhere from 100 to 120 grams of flour per cup. What about you? How many grams of flour do you get in a cup? Do you use weights or volumes, UK or US or metric or something else, in your cooking? And why?