Weight vs. Volume


Not all Cups are Created Equal

Learning to bake as a child in Canada, I was always taught to measure ingredients in cups, tablespoons, and teaspoons.  This is not surprising, since the majority of North American cookbooks list ingredients with these measurements. In order to keep measurements as accurate as possible, I was taught to scoop up ingredients and then level them with the back of a butter knife. My baking endeavours always seemed quite successful using this method (unlike my cooking endeavours but let’s not get into that) so I never gave much thought to using measuring cups. That is, until I moved to Europe. All of a sudden, I didn’t own measuring cups anymore and no stores seemed to sell them (my roommate ended up having some sent over from Canada.) During this brief period when I was measuring cup-less, I still managed to cope using a measuring jug with millilitres. Knowing that 1 cup = 250 mL, I thought that using my measuring jug would be simple enough, until I realized that 1 Canadian cup and 1 American cup are not actually the same thing.  After some Wikipedia research, and since it’s on Wikipedia, it must be true, I learned that 1 cup can vary between 200 – 284 mL depending on which country you are in. Well that is just great.

Consistency and Accuracy

But still, as long as you are being consistent with your measuring cup (i.e. not measuring flour in a Canadian cup and sugar in an American cup- if you are doing that, I think you have other problems to worry about) it shouldn’t matter what type of cup you are using…to a certain extent. Even if you are consistently using the same method of measuring for your entire recipe, you can run into another problem. The volume of ingredients can change quite a lot, depending on certain conditions. This is mostly the case for dry ingredients. Liquid ingredients can change in volume at different temperatures, for example, but for baking purposes, this is pretty insignificant. Dry ingredients, on the other hand,  can change in volume way more easily. For instance, there is a big difference between 1 cup of sifted flour and 1 cup of flour, sifted. The former means that you are sifting flour into the measuring cup while the latter means means you are taking 1 cup of flour and then sifting it. Because unsifted flour is more compact than sifted flour, you have more weight in 1 cup of unsifted flour than you do in 1 cup of sifted flour. On the other hand, 100 g of flour is 100 g of flour, whether or not it is sifted. This doesn’t just go for flour, either. Take a look at brown sugar. If you pack down the brown sugar into the measuring cup really well, you will have more sugar than if you just simply scoop it up.

What is the simple way to avoid these variations in volume for dry ingredients? Any pastry chef will tell you to use a scale. I started doing this when I moved to France because this is just how they do it over there. European cookbooks are all listed in grams for dry ingredients and millilitres for liquids.  When using French recipes, I had no desire to try and convert grams of various ingredients into volumes. Also, my roommate’s Canadian measuring cups stayed with her in Scotland and I was once again measuring cup-less. So, I finally gave in to the European way. It turns out, not only is weighing ingredients more accurate, it is way easier too. No more washing measuring cups; just weigh everything into the bowl and be done with it.

Baking = Science

Using a scale in the kitchen made me think me of working in science. We never measure dry ingredients by volume in the lab because it just isn’t consistent. Two of the most important  things in designing experiments are consistency and reproducibility. When you conduct an experiment, someone else on the other side of the world should be able to conduct the same experiment and have the same results. There are already so many factors, such as temperature and humidity, that can influence the results of your experiment that you really don’t need another factor that could potentially mess things up. The difference in how someone might scoop up a powder as opposed to how you would do it, is a factor that can be controlled by using a scale. However, while extremely important in the lab, this may not matter for certain recipes in the kitchen.  For example, my oatmeal cookies are pretty forgiving if you add too much or too little of certain ingredients. On the other hand, some recipes will turn into complete fails if you are even off by the slightest amount. Parisian Macarons are such an example. They are so finicky you would never want to try this recipe without a scale (surprise, surprise, they are French.)

The Downsides of Using a Scale

Measuring ingredients by weight rather than volume does, however, have a few downsides. Like many North Americans, if you don’t own a kitchen scale…umm good luck weighing ingredients. The upside to this, is you can find scales for pretty cheap these days. I recently bought a scale for around $30 CAD, and it is pretty good quality. You also can find ones that are even cheaper. One warning, though, if you decide to use a cheap spring scale over a digital one: it won’t be as precise. A spring scale leaves room for human error when you are required to line up an arrow to the tick marks on the scale.  I personally would rather measure by volume than use a spring scale, but that is just me. Yes, I am so lazy and impatient that I find lining up arrows and tick marks to be too much work. I feel the same way about analog clocks that don’t have numbers on them, but I digress. I would highly recommend purchasing a digital kitchen scale if you don’t already have one. They  usually allow you to convert between units of measurement such as grams and ounces. You can also tare your weight between measurements, which means you can add your first ingredient, tare the weight back to zero, add your second ingredient, tare the weight and so on.

The only other real concern when using scales is the accuracy of the scale itself. If the scale is damaged, it might give readings that are way off the actual weight. Luckily, there is an easy way to test this. Water has a density of 1 g/mL, which means that 1 mL of water will weigh 1 g. To test the accuracy of your scale, measure a certain volume of water. If the weight in grams equals the volume in millilitres, then you are good to go. Even if it is off by a few grams, that is fine. Otherwise, you may need to get your scale calibrated, or get a new scale.

So, long story short. I recommend getting a digital scale. It has made my baking experience so much easier. I do realize that some of you will read this, say “that’s nice,” and go back to using your measuring cups and that is totally fine. This is why I, being the totally awesome and accommodating person I am, will be listing the ingredients in my recipes by both volume and weight. This way everyone should be happy. You will notice very small amounts of dry ingredients (such as baking powder and baking soda) will still be listed in teaspoons and tablespoons. Unless you have a high precision scale, measuring such small amounts with a typical kitchen scale is not going to be that much more accurate so I am sticking with teaspoons and tablespoons. Plus the French, aka pastry masters of the world, use grams for most ingredients but will still use cuillère à soupe (soup spoon) and cuillère à café (coffee spoon) for ingredients such as salt or baking powder. And, if the French do it, it’s good enough for me.

Click here for a list of useful measurement conversions.


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