Oloroso ("scented" in English) is a variety of fortified wine (sherry) made in Jerez and Montilla-Moriles and produced by oxidative aging. It is normally darker than Amontillado. Oloroso is usually dark and nutty.
Unlike the fino and Amontillado sherries, in oloroso the flor yeast is suppressed by fortification at an earlier stage. This causes the finished wine to lack the fresh yeasty taste of the fino sherries. Without the layer of flor, the sherry is exposed to air through the slightly porous walls of the American or Canadian oak casks and undergoes oxidative aging. As the wine ages, it becomes darker and stronger and is often left for many decades.
Oloroso sherry is also the base for many of the sweet sherries developed for the international market, such as Bristol Cream, in which oloroso is sweetened and sometimes has the color removed by charcoal filtering to achieve the desired effect.