Red wine vinegar

One US cup of red wine vinegar weighs 239 grams (8.4 ounces). Going the other way, 100 grams is about 0.42 cups.

Also called wine vinegar, Italian red wine vinegar, aged red wine vinegar.

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

A cup of red wine vinegar weighs 239 g (8.4 oz), a density of 1.010 g/mL, 1% heavier than the same cup of water. A tablespoon weighs 14.9 g and a teaspoon 5 g. USDA weighs a cup at 239 g, and Roland's 6% red wine vinegar packs 33.81 lb into four 1-gallon jugs, 1.013 g/mL or 239.6 g per cup.

Red wine vinegar is red wine fermented a second time by acetic acid bacteria, which turn its alcohol into acetic acid. Supermarket and foodservice red wine vinegars are usually diluted to 5 to 7% acidity; Roland's is 6%. The wine leaves a little of itself behind: colour, tannins, glycerol and minerals, but almost no sugar, since the yeast fermented that away before the vinegar was made. USDA's record lists 94.5 g of water per 100 g, 0.27 g of carbohydrate and no sugars. It is the vinegar of Italian and French vinaigrettes, pickled red onions, marinades and pan sauces.

The physics predicts the weight. Acetic acid solutions weigh 1.0052 g/mL at 5% and 1.0121 at 10% at 20 °C, so a 6% vinegar weighs about 1.007 g/mL from the acid alone, and the wine extract adds a few thousandths more, for 1.009 to 1.013 g/mL. USDA's Standard Reference record for red wine vinegar (FDC 172240) weighs a cup at 239 g, 1.010 g/mL. Roland's case of four 1-gallon jugs has a net weight of 33.81 lb, 15,336 g in 15,142 mL, which is 1.013 g/mL and 239.6 g per cup. The two agree within 0.3%, and USDA's cup is published.

Like other vinegars, red wine vinegar is labelled by volume: Roland's sheet gives the serving as 1 Tbsp. (15 mL), the FDA reference amount for vinegar, with no grams. Grams equal to millilitres would be almost right for vinegar, 15 g against a true 15.1 g, which is why vinegar is one of the few condiments where measuring by volume costs nothing.

White wine, champagne and sherry vinegars are made the same way at similar strengths and should weigh within a gram or two per cup of red wine vinegar; this entry does not measure them. Balsamic vinegar of Modena is a different product, cooked grape must blended with wine vinegar, and weighs far more because of its sugar.

Practical guidance: use 239 g per cup, 119.5 g per half cup, 60 g per quarter cup, 14.9 g per tablespoon and 5 g per teaspoon. For a classic vinaigrette at three parts oil to one part vinegar by volume, 3 tablespoons of olive oil weigh about 40 g and 1 tablespoon of red wine vinegar 15 g. A 12.7 fl oz bottle holds about 380 g.