Émile Peynaud (June 29, 1912 – July 18, 2004) was a French oenologist and researcher who has been credited with revolutionizing winemaking in the latter half of the 20th century, and has been called "the forefather of modern oenology".
Peynaud entered the wine trade at the age of fifteen with the négociant Maison Calvet. At Calvet he worked under the chemical engineer Jean Ribéreau-Gayon, and they developed methods of analysing the wines that were to be purchased. In 1946, Peynaud completed his Doctorate at the University of Bordeaux and joined its faculty as a lecturer. Ribéreau-Gayon at this time was also teaching at the University, and the two shifted their previous focus of problems faced by Calvet to the problems faced by the winemakers themselves.
While at the University of Bordeaux, where he became a professor of oenology, Peynaud worked at providing scientific explanations for many problems encountered in the process of winemaking. He convinced the wineries to begin picking of grapes at vineyards up to two weeks later than usual, and to complete the picking as quickly as possible. The practice of also picking underripe or rotten grapes was abandoned, so that the selected fruit arriving at the winery was of the best possible quality.