The riurau is a very emblematic building of these regions and unique in the world. It is a building with a gallery or open porch with lowered arches that was used to dry grapes and convert them into raisins. It should also be noted that the correct orientation of the riurau is towards the south, although some are oriented towards the east, but never towards the north or west. Why? Because the main function of the riurau is to serve as a place to make the raisins: the orientation which gives more hours of light is towards the south (between east and west, the sun warms it all day). The origin of these buildings can be found in the 19th century, the golden age of the raisin industry, when it was considered a luxury for the palate. At that time, they could be compared to chocolates.

At first, the raisins were dried in the air on reeds, nothing else. This is called pansa vera (literally, true raisin) but, little by little, the production and techniques were improved. The production process was industrialised and people realised that if the raisin was scalded, the skin would open, which favoured a much faster drying procedure, helping to improve the final fruit since it remained more tender. Moreover, they added bleach or caustic soda to the cauldron with boiling water and a mountain plant that gave it a beautiful golden colour, the false yellowhead, also called in Valencian jolivarda, matapuces or botja melosa.