One of the handiest cooking factoids in our crazy US measurement system is that there are 4 tablespoons in a quarter cup. If you are doubling a recipe for a sauce that calls for 2 tablespoons of flour, don’t measure 4 tablespoons, just measure 1/4 cup and you’re all set.
So I was a little surprised when I was looking at a source I consider reliable (Samuel Fromartz’s In Search of the Perfect Loaf, p. 87) to see “Mix 3 tablespoons (30 grams) lukewarm water…” Now, “everyone knows” that a tablespoon is 15 ml, and 1 ml of water weighs a gram, so 3 tablespoons of water should be 45 grams. OK, precision is overrated in cooking, but it is more important in baking, and this is a 50% difference (45 being 50% more than 30), and that is actually significant.