One cup, many weights

September 1, 2024 by
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One of our Members recently emailed us a question that has likely been pondered by bakers ever since the kitchen scale was invented: just how much does a cup of flour weigh? While I have extolled the virtues of weighing ingredients before, I did not focus on the weight of flour specifically, although it is arguably the most critical weight for baking. There are some ingredients for which weight is fairly standard: almost everyone agrees that a cup of granulated sugar weighs 7 ounces/200 grams. One cup of chocolate chips almost always clocks in at 6 ounces/170 grams, and a cup of honey will generally be 12 ounces/336 grams. When you get to other liquids, things start to vary slightly, and when it comes to flour, all bets are off. King Arthur Baking’s Ingredient Weight Chart lists 4.25 ounces/120 grams for one cup of all-purpose flour. America’s Test Kitchen, on the other hand, says that a cup of flour weighs 5 ounces/140 grams. That is a significant difference in a bread recipe that uses four or more cups of flour! So what gives with the discrepancies?

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One thing you will note about the ingredients that have static weight measures is that they do not compact. That is to say, if you pour granulated sugar into a measuring cup, you are not going to be able to cram in much more by tapping the cup on the counter or pressing down on the sugar. The same goes double for liquids – they do not compress in the slightest except under extreme pressures (Hydraulics 101). On the other hand, a cup of flour, whether wheat, oat, rye, or another grain, can be significantly compacted just by tapping the measuring cup on the counter. Anyone who has filled a container with flour has experienced this phenomenon: when you pour the flour into your storage vessel it takes up more room than it did in the bag. Give the container a few gentle bumps and the flour settles right in.

Therefore when converting a volumetric measure of flour to a weight measure, the results depend on how the flour is added to the measuring cup. Some bakers use the spoon-and-sweep method. This means they will use a spoon or scoop to take the flour from its storage container and add it to the measuring cup until the center is piled higher than the rim. They then level the flour using a flat surface such as the back of a knife. Other bakers prefer the scoop-and-sweep (aka dip-and-sweep) method, where the measuring cup is dipped directly into the flour and any excess above the rim is leveled in the same way as the former method. Spoon-and-sweep will yield around 4.5 ounces/125 grams of all-purpose flour. The scoop-and-sweep method will result in around 5 ounces/140 grams per cup. Both methods depend somewhat on how the flour has been placed into its storage container. If the flour was crammed in, it will weigh more (especially using the scoop-and-sweep method) than if the flour has been fluffed up prior to measuring. If you sift the flour before spooning into a measuring cup, it will weigh even less.

Another factor that affects the weight of the flour is the grinding method. Most all-purpose flour today is milled using stainless steel rollers which results in a fairly fine texture. Stone-milled flour will have a coarser texture and therefore it will weigh less per cup because the larger, more irregular grains do not compact as much. Impact-milled flour (a rarity) will be very fine and weigh more per cup. The type of flour also plays a role. Cake flour, which is made from low-protein wheat, weighs less (generally 4 ounces/112 grams per cup) than all-purpose or bread flour, which are both milled from high-protein wheat. Whole wheat flour is coarser and weighs less than all-purpose.

So what is a baker to do when a recipe does not provide a weight measure? If the recipe is in a cookbook, the first thing to do is to read the book’s introduction. The author will often explain how he or she measures flour which will allow you to infer an approximate weight. The same goes for recipe websites or blogs: the writer may have a pinned post or guide where she explains her technique. You may need to do a little trial and error to determine the sweet spot for a particular author, but once you find a measurement that works, be sure to write it down! If the recipe is from a friend or family member, ask them how they measure the flour, or better yet, make the recipe with them. That’s how I learned how my grandmother measured flour (scoop-and-sweep).

If I am unable to find an explanation, I have learned that using 4.5 ounces/125 grams for all-purpose flour is a good starting point. If the recipe calls for sifted flour, I will use 4 ounces/120 grams per cup. I try to err on the side of using too little flour because you can usually add more if the batter or dough doesn’t look right, but it’s impossible to remove any once you have mixed everything together. Most importantly, don’t let uncertainty about weights keep you from baking! Although you might have a dud once in a while, recipes are generally more forgiving than you might think. Start on the lower end of the weight scale and use the descriptions in the recipe to guide you. If it says to scoop a cake batter into the pan and then level it, that means the batter should be fairly stiff. If your batter is runny, add more flour. If the dough is really sticky and the recipe says it should be smooth, that’s another sign to add more.

Finally, don’t let perfection become the enemy of good. Even a less-than-perfect homemade cookie is going to be better than most commercially-produced cookies at the grocery store. Also, you can usually salvage something even when disaster strikes. Last week I had a major failure with a chocoflan that didn’t hold its shape. The custard flopped over and broke apart, and the cake base wasn’t much better. I scooped up the chunks of custard and cake, chucked them into a bowl, and rebranded it as a trifle. It may have looked frightful, but it still tasted great.

Category: Cooking Tips

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15 Comments

  • Indio32  on  September 1, 2024

    About 99% of Americans I’ve asked (mostly sub-forty) about this say they use scales. A few have alluded to this being an issue of cookbooks and cooking shows perpetuating the cup measurement system because that’s they way it’s always been done. In my own collection I’m increasingly noticing US recipes using both systems. I guess it’s the same as UK vs US cookbook cover design. Ottolenghi being a case in point. UK design can be much abstract whereas the US cover design HAS to show an image of food. US publishers having always shown food photos on covers so are scared that changing might impact sales so nothing changes or if it does its very very slow. I believe that Ottolenghi UK cover designs are wildly popular in the US.

  • SheilaS  on  September 1, 2024

    If weights aren’t included throughout, I always appreciate when the author at least specifies it in the intro. If not, I start with 125g/cup for AP flour. I always keep Jessica Reed’s handy little book, “The Baker’s Appendix” with me in the kitchen. It has handy conversion tables for all types of flours and baking ingredients.

  • Thrasymachus  on  September 1, 2024

    I refuse to use any baking recipe that solely uses the cup measurement system. I cannot see how you can achieve the same level of accuracy as you do when using scales.

  • KatieK1  on  September 1, 2024

    Thanks for the math!

    Another issue is what kind of salt is used. Some cookbook writers’ default is kosher, and then some don’t specify Diamond or Morton’s.

  • Rinshin  on  September 1, 2024

    Regarding kosher salt, Kirkland brand of kosher salt is so different from Morton or Diamond. Bigger flakes and to me much saltier using the same amount. I have to reduce by more than half.

  • Rinshin  on  September 1, 2024

    I started my baking using older cookbooks esp those published by groups such as officer’s wives, community, church, etc and those were never metric. I did not make complicated baked goods but mostly layered and sheet cakes, cookies, pies, and simple bread types. They came out fine. The American style cakes were not the fine crumbed Euro or Asian style cakes so perhaps it was not that critical to be precise. Same went with pizza dough. Now when I am making Neapolitan or other pizza doughs from newer cookbooks, I weigh the ingredients.

  • KatieK1  on  September 1, 2024

    Also with the older cookbooks, they probably used salted butter, while hardly any of the more recent cookbooks do.

  • FuzzyChef  on  September 2, 2024

    There’s one thing worse than recipes that don’t give a weight: ones that give definitely wrong weights.

    I buy a premium brand of masa harina for tortillas. The bag has proportions on it that have both volume and weight, which included 165 grams to 1 cup. There is no way, no matter how much you compact, that you can get 165 grams of masa into 1 cup. Maybe with a hydraulic press.

    My plea to recipe writers: if you’re going to offer weights, please have at least tried to weigh them yourself? Or don’t give them.

  • LeilaD  on  September 2, 2024

    High altitude scoop-and-sweep, but I have to adjust every single recipe I come across. A “couple of ounces” really does make a difference one way or another above seven thousand feet. My kitchen is a tiny one with no room for a scale- I had to get rid of about half my kitchen things when I moved in here- American under 40. Of course, my mother is over 70 and many of my cookbooks are from the 1970s or older…

  • averythingcooks  on  September 2, 2024

    I absolutely agree with Fuzzychef! As a Canadian, I am used to using both measurement systems while everyday loving my little digital scale a little bit more 🙂 and I do appreciate that some authors/publishers are trying to give measurements in both systems BUT please make sure they are correct! Off the top of my head I can think of 3 recipes I’ve used that made clear mistakes. Sometimes it is more like a “did you even try weighing that volume of yogurt?” and other times its just basic conversion/math errors. NO… 2/3 cups of a liquid does NOT = 120 mL) and NO, 1 lb of little potatoes does NOT = 900 g.

  • ozfoodie  on  September 3, 2024

    I’m with Thrasymachus. These days I will not knowingly buy a book that doesn’t specify metric weights, and flick right away from online recipes that don’t. There are too many amazing recipes that do use them for me to waste my time with guesswork. 🙂

  • Cookie24  on  September 3, 2024

    I also agree with Thrasymachus. I already own too many cookbooks to purchase an another cookbook that only uses cup measurements. Any new book I buy must at least have both measurements, or it just doesn’t make the cut to be included in my collection. I also don’t purchase books that use cups and ounces; gram weights are so much more accurate. When baking something from an older cookbook I use 125g/cup for AP flour and handwrite the measurements in the cookbook itself for later reference. When I create a recipe myself, I always write it using metric measurements, even for non-baked dishes. Whomever ends up with my recipes when I’m gone probably won’t appreciate the metric measurements or maybe by then it will be more widely used in the US.

  • FJT  on  September 4, 2024

    I’m with Thrasymachus, I don’t even try to make baking recipes that don’t specify weights (preferably metric). I have coeliac disease and use a wide variety of flours, and I’d be in a right pickle if I tried to use cup measures to bake gluten-free bread.

  • vglong29  on  September 4, 2024

    I’ve noticed similar issues with 1 cup of packed brown sugar. The Baker’s Appendix says this is 220 grams, quite a bit more than 200 grams for granulated sugar. Several recipes I’ve seen just says 200 grams for brown sugar, same as granulated. When I pack brown sugar, it can be even more than 220 grams. And I’ve seen many cookbooks with weight measurements but the amount of flour varies recipe to recipe. Like others, I just started using the same “standard” weights across recipes that aren’t specified and they come out fine.

  • veronicafrance  on  September 6, 2024

    I’d just like to say I have a tiny kitchen. My flat digital scale slides easily into a drawer. If you’re seriously into baking, a scale is essential, not optional. Admittedly, some things can work by eye — my mother in law never measured her Yorkshire pudding ingredients, she just judged when the batter was thick enough and they were perfect every time. But if you want predictable results for bread or cakes, weighing is the only way.

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