Today, we picked the field blend with Mum and Dad. 320kgs from the home vineyard. The field blend will eventually be bottled as a vineyard block blend of Grenache, Shiraz and Mataro.
Essentially, a field blend requires more than one grape variety planted together in the same vineyard. All the grapes are picked at the same time and fermented together—a true field blend doesn't separate by variety at picking; the "blend" is whatever the vineyard provides in that given vintage.
Modern winemakers generally prefer to plant and pick each variety separately, knowing that they don't always ripen evenly. Sometimes a winemaker will ferment multiple grapes together (a practice called co-fermentation), which invokes the spirit of field blends. But most winemakers blend different lots of wine together after the fermentation is finished to better control the process.
Vintage conditions this year gave us a rare opportunity to pick all 3 varieties (Grenache, Shiraz and Mataro) in a particular vineyard block together. They will be co-fermented before filling a single second use French oak barrel. Look out for the wine in 12 months time, it should be something special, and may be a while before the opportunity presents itself again.