McLaren Vale and Barossa Valley are the prime regions for serious Grenache in Australia. But it is also interesting to compare two Grenaches from the same region, but different sub-regions, in this case in the Barossa. The two wines were the 2006 Kalleske Old Vine Grenache and the 2006 Cirillo 1850 Old Vine Grenache. Both wines are made from very old vines, at least 70 years old, but many over 100 years old. They are high quality wines.
However, the results are quite different. And I believe this is at least 2/3rds due to terroir, and maybe 1/3rd to winemaking. Terroir is often associated with soil, but it is much more than that. However, rainfall and temperature would have been quite similar for these two wines, whereas the soil is very different.
The Cirillo Grenache is grown on the valley flats near Nuriootpa. The soil is alluvial and very sandy. The Grenache is mellow, soft, and aromatic, and the tannins are quite soft. These are typical expressions for this type of soil.
The Kalleske Grenache is made from grapes grown on red-brown earth, where clay and iron are major components. The wine is much more muscular, the wine has a more angular feel, the alcohol is more noticeable (although the Cirillo has high alcohol as well), and the tannins are firmer.
Pay attention to terroir, in particular when you plan to drink premium wine.
Some scientists claim that vines can only take up sunshine and water, but there is clearly more going on. Have you had similar experiences?