Grape-Nuts

One US cup of Grape-Nuts weighs 116 grams (4.1 ounces). Going the other way, 100 grams is about 0.86 cups.

Crumbs and cereals compared: cup weights side by side, the source behind each, and why they differ.

A cup of Grape-Nuts weighs about 116 g (4.1 oz), and half a cup 58 g. USDA's record and King Arthur Baking's chart agree within 1.8%; Grape-Nuts weighs about as much per cup as flour and four times as much as corn flakes.

Grape-Nuts is a breakfast cereal made by Post since 1897 from whole wheat flour, malted barley flour, salt and yeast, baked into a loaf, dried and ground into small, hard, crunchy nuggets. Despite the name it contains neither grapes nor nuts. Besides breakfast, it is a baking ingredient in New England: Grape-Nuts bread, Grape-Nuts custard pudding, muffins, crumb toppings and the base of some pie crusts and granola-style bars.

USDA's record for Post Grape-Nuts weighs the cereal's serving of half a cup at 58 g, 116 g a cup; Post's own label gives the same half cup, 58 g, and is listed without a figure so that it is not counted twice. King Arthur Baking's chart lists half a cup of Grape-Nuts at 2 oz, 57 g, 114 g a cup. The two are 1.8% apart, inside the 10% this site allows for cereals and other milled ingredients, so this site publishes USDA's 116 g. Confidence is medium: there are two sources, and USDA's rests on the maker's serving.

The physical check: Grape-Nuts are small, dense, irregular nuggets of baked wheat and barley, hard and only slightly porous, and they pour and settle like coarse sand. At 116 g a cup, about 0.49 g per millilitre, they pack like other small hard granules. That makes Grape-Nuts one of the heaviest cereals by the cup, close to all-purpose flour, which weighs 120 g a cup spooned and levelled on this site, and four times heavier than flaked or puffed cereals such as corn flakes and crisp rice at about 28 g. Because the nuggets are hard and roughly round, the cup is easy to fill evenly, and one level cup is much like the next.

Practical guidance: use 116 g per cup of Grape-Nuts, 58 g per half cup and about 7.2 g per tablespoon. A 20.5 oz box (581 g) holds about 5 cups. In baking, Grape-Nuts are usually soaked first, in milk for puddings or in hot water or buttermilk for breads; unsoaked, they stay hard and gritty in a batter. When swapping Grape-Nuts into a recipe that calls for a flaked cereal, go by weight, not cups.