Tim Teichgraber has an interesting article in today's SFChron on field blends. A couple of comments:
1. He refers to old pre-Prohibition growers working w/ odd varieties, including Roussanne. First time I'd heard of any old Roussanne being planted in Calif. Wonder if any of it survives?
2. He refers to "co-fermentation" being any fermentation of mixed varieties together; Zin/Carignane/PS/etc. The only way I've heard of the usage is fermentating a bit of white varieties w/ reds to get enhanced color extraction (co-pigmentation).
3. He says Sean Thackrey "believes to be" the Rossi vnyd is mostly Syrah. My understanding is that the Rossi vnyd is mostly PetiteSirah.
4. He quotes Will Bucklin as asserting the red-variety vines naturally have longer lives than white varieties. That's why all the old-vine vnyds are reds. Never heard this claim before.