Most techniques of manipulation arose from need. Early wine had many wine faults that caused a wine to spoil quickly. Classical writings from the Greeks and Romans detailed recipes that could cure "sick wines". These include adding various items like milk, ground mustard, ashes, nettles, and lead. Another example of early "manipulation" that became accepted, common practice was the process of adding grape spirit to wine made in the Douro region of Portugal. This process of fortification gave the wine chemical stability for long sea voyages and, when added during the fermentation process, left the wine with a balance of residual sugar and alcohol content that gave the wine a unique taste. This style of wine became very popular on the world wine market. Today the accepted way to make Port is to "manipulate" it by adding brandy during the fermentation process.