Coconut water

One US cup of coconut water weighs 240 grams (8.5 ounces). Going the other way, 100 grams is about 0.42 cups.

Also called fresh coconut water, tender coconut water, young coconut water, packaged coconut water, 100% coconut water.

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

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

A cup of coconut water weighs 240 g (8.5 oz), a density of 1.01 to 1.02 g/mL, only about 2% heavier than water. USDA weighs a cup at 240 g, and a laboratory study of tender coconut water measured its specific gravity at 1.020, 241 g per cup.

Coconut water is the clear liquid inside a young, green coconut, drawn off before the flesh hardens, not to be confused with coconut milk, which is made by pressing grated coconut flesh with water and is thick with fat. Packaged coconut water is the same liquid, pasteurized or cold-filtered; some brands add sugar or fruit juice, which makes them slightly heavier.

USDA's Standard Reference record for coconut water (NDB 12119) gives 1 cup as 240 g, with 228 g of water and 6 g of sugars, 95% water and 2.5% sugar. Purohit and colleagues, studying how heat changes the colour of tender coconut water, measured water from 7 to 8 month old coconuts at a specific gravity of 1.020 and 5.04 °Brix, about 1.018 g/mL, 241 g per cup. The two agree within 0.5%. Confidence is medium because there is one laboratory measurement and USDA's 240 g could be a rounded figure.

The physical check: a liquid that is 95% water with about 5% dissolved sugars and minerals, mainly potassium, should weigh about 1.02 g/mL. A sugar solution at 5 °Brix weighs 1.018 g/mL by the USDA sucrose table, the same as the measured coconut water. That puts it at the light end of everything sold as juice, well below orange juice (248 g per cup on this site) or apple juice (248 g), because it carries about half the dissolved solids.

On this site it sits with the other coconut products. Coconut milk and coconut cream weigh about the same per cup, 224 to 241 g, because their fat is lighter than water and offsets the dissolved solids; cream of coconut, a sweetened syrup, is far heavier at 283 to 312 g.

Coconut water from older, brown coconuts carries less sugar and more of the coconut's oil than water from young green ones, and some packaged brands blend water from coconuts of different ages. Neither shifts the cup weight by more than a gram or two, because all of it is about 95% water; what changes is the taste, not the weight.

Practical guidance: use 240 g per cup, 120 g per half cup, 60 g per quarter cup and 15 g per tablespoon. An 11.1 fl oz (330 mL) carton holds about 1.4 cups, 336 g. In baking and smoothies coconut water can replace water nearly gram for gram; measured by volume, a liquid measuring cup is accurate enough.