Weight vs. Volume Measurements in Cooking

8 April 2009
By

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?

Tags: , , , ,

5 Responses

  1. #1
    Katherine 

    It can get confusing! When I was living in germany, I used to be able to do the conversions in my head. But I am out of synch with it so when I need to do a conversion now, I have to think about it.

    Katherine’s last blog post..A Lesson in Sales at the Nail Salon

  2. #2
    Laurie 

    And I still can’t keep a quart and a gallon straight – I seem to use them interchangeably. Which would be another reason for me not using them…

    It’s kind of like the verbs “to lend” and “to borrow” – I get those confused, too. Long story…

    I can still do most volume conversions in my head, too, as long as it doesn’t involve quarts or gallons, but metric is just so much easier all the way around. Easier to deal with, easier to scale recipes up or down. And weights? No more messing up all the measuring cups – just dump everything into the same bowl and stop when the scale reaches the correct point…

    Of course, I really need an electronic scale, not this plastic piece o’ crap spring scale that I’ve been using… 😀

  3. #3
    bongo 

    A UK cup is 9 ounces, where a Canadian cup is 8 ounces – an expert, eh?

  4. #4
    Laurie 

    Is it? I’ve seen references to a UK cup being 8 ounces. Interesting. I may have to research that more. 🙂

  5. #5
    Momma Snider 

    What I’ve found is that most of the time the slight differences don’t matter. I was taught to fluff up the flour before measuring, and then level off the cup. For brown sugar, I was taught that it should always be packed. I got to thinking about all this when I was looking at fudge recipes one Christmas. In the same cookbook, there were two recipes that called themselves See’s Fudge. First of all, does See’s even sell fudge? I don’t think so. But these recipes were identical, EXCEPT one called for 1 cup of butter, and the other called for 1 tsp, just enough to grease the pan. Crazy. They’re both good, and what I usually do is meet in the middle, with 1/2 cup of butter.

Leave a Reply

About LMAshton

Howdy and welcome to my site! I'm Laurie and I'll be your, er, hostess today. :)

I'm a Canadian expat currently living in Singapore. I'm married to a Sri Lankan and lived in Sri Lanka for nearly a decade. We also lived in New Zealand for half a year.

I cook Sri Lankan curries, sambols, and mallungs. I bake bread using wild yeast (sourdough that isn't sour). I bake on the stove. I experiment with Indian / Malaysian / Indonesian / Thai / whatever cuisines interest me. And I experiment wildly.

Life is an adventure. Join me! :)

If you want to know more about me, click on the "About" link in the navigation bar above. :)