A cake recipe calls for 1½ teaspoons of baking powder and serves 8. You want to make it for 20 people. How much baking powder should you use?
A3¾ tsp (exact 2.5× scale)
BAbout 2½ tsp (less than proportional)
C3 tsp (double, rounding up)
D1½ tsp (leavening never scales)
Leavening agents like baking powder don't scale linearly with the batch size. Using 3¾ tsp (exact 2.5×) would likely produce a dense, over-risen, or bitter result. Professional bakers typically use 75–80% of the proportional amount for large scale-ups. The other ingredients (flour, sugar, butter) do scale linearly, but leavening is a known exception.
Question 2 True / False
A US recipe calls for 1 cup of liquid. A UK baker measures 1 imperial cup. They have used the same amount of liquid.
TTrue
FFalse
Answer: False
A US customary cup is 240 mL, while a UK imperial cup is approximately 284 mL — nearly 20% more. For most cooking this gap is forgiving, but in baking (where ratios of wet to dry ingredients are critical), using the wrong cup size can noticeably affect texture and rise. This is why reliable baking recipes increasingly specify weight in grams rather than cups.
Question 3 Short Answer
A recipe uses 2 cups of all-purpose flour. You measure by scooping a cup directly from the bag. Why might your result differ from the recipe's intended amount, and how can you avoid the problem?
Think about your answer, then reveal below.
Model answer: Scooping packs the flour, which can add 20–30% more flour than intended. The fix is to spoon flour lightly into the measuring cup and level it off, or better yet, use a kitchen scale and weigh the flour in grams.
Volume measurements of dry ingredients are inherently imprecise because density varies with how the ingredient is packed. A scooped cup of flour weighs roughly 150 g, while a properly spooned cup weighs about 120 g — a 25% difference. That excess flour makes cakes dense and dry. Weight (mass) measurements eliminate packing variation entirely, which is why grams are the standard in professional baking.