Sometimes, in some areas, the vine needs to suffer a little, to be under stress, to produce the best possible grape quality or appropriate alcohol content for the wines of the DO Penedès.
The vine is a hardy, rustic plant, adapted to difficult conditions like drought and poor soils. In the Penedès in years with high rainfall, sowing grasses and/or legumes between the vine rows will consume some of the water that otherwise the vines would have taken up and thus stress the vines.
The plant has defence mechanisms and when it is under stress, it accumulates sugars so that the fruit ripens quicker and the plant can be free of it quicker as the seeds fall earlier in an attempt to favour its reproduction.
Once these grasses are cut, they are ploughed back into the soil as organic material and fertiliser.
Other curiosities in the category: Vineyard