tonneau, traditional Bordeaux measure of wine volume, once a large wooden cask holding 900 l, or 252 imperial wine gallons, the equivalent of four barriques. A paris tonneau was 800 l, but, because of the prominence of gascon merchants in London and English merchants in Bordeaux, the Bordeaux measure became the standard. By the end of the 18th century, tonneaux had been replaced by the easier to transport smaller barrique, yet the tonneau, the exact equivalent of 100 cases of wine, is still the measure in which the Bordeaux wine trade deals.
