Here I’m going to describe my basic method of how to count carbohydrates in something I am cooking from scratch. I’ll be using a bread recipe from the 1961 Betty Crocker’s New Picture Cook Book to illustrate the procedure.
I start out making the bread according to the recipe, measuring more carefully that I perhaps would otherwise.
When carb counting, first I add up the carbs in a batch of bread. In the case of this recipe, yeast, water, salt, and shortening have no carbs. The ingredients that do have carbs are 7 cups of flour and 3 tablespoons of sugar. I know that King Arthur flour has 88 grams of carbs a cup, so there are 7×88=616 grams of carbs in flour. Each tablespoon of sugar has 12 grams of carbs per tablespoon, so there are 3×12=36 grams of carbs from sugar in the bread. Further, 36+616=652 so the whole batch of bread has about 650 grams of carbs.
When the bread comes out of the oven and out of the pans, I weigh both loaves (in grams, not ounces). The loaves weighed 738 and 746 grams. Thus, the total weight of bread made from this batch is 1484 grams.
Then I divide 652 grams of carbs by 1484 grams mass to find a carb factor of 0.45 for this bread.
My child’s portion of bread weighed 56 grams, so she ate 0.45 x 56 = 25 grams of carbs from bread. I record this carb factor of 0.45 both in the cook book and someplace where I can find it easily until the bread is gone.