Ouillage | French term for both ullage and topping up, eg. of barrels. In the Jura wine-growers may offer two identical barrel-aged wines, one kept topped up (‘ouillé’) to avoid oxidation, and the other left untopped (‘non ouillé’) and thus left to ullage, the amount of ullage being the quantity of liquid allowed to evaporate. The intention of ‘non-ouillé’ winemaking is to produce a wine with oxidative (“nutty”) characteristics, sometimes under a veil (‘une voile’) of naturally-occurring form-forming yeasts.