Rodney Strong Wines (non-2007, see notes) is Not Vegan Friendly

Company email (May 2018)
"Sorry, none of our wines are vegan."

Company email (November 2011):
"None of our wines are technically vegan friendly, as we use some natural fining agents like egg white in our reds and isinglass (from fish) in our whites. All of these are filtered out in the end, but some vegans prefer that nothing animal be used whatsoever, so I thought I should be totally up front with you on this matter."

Company email (November 2011):
"Yes, all of our wines are fined with either egg whites or isinglass, and sometimes gelatin. We process all of our wines here at the winery in Healdsburg, CA."

Company Email:
"The use of fining agents in winemaking to make wine taste/smell/look better is an ages old practice. Fining can eliminate bitterness, astringency, brown color, cloudiness, and other things best left out of wine. After the fining agent is added to wine, it clings physically or electrostatically to whatever protein or other targeted substance in the wine, and gravity generally brings it to the bottom of the storage vessel. The wine can then be drawn off the sediment, and may or may not be subjected to filtration. Some fining agents are "earth" based, and some are "animal" based. While theoretically no fining agent will end up in the final wine, strict adherents to some versions of vegetarianism would prefer not to make use of any product if animal derived substances were used during processing.
Fining is never done formulaically. Rather, if a wine might be subject to some improvement in, let's say astringency, then a representative sample of the wine is trialed under laboratory conditions with a variety of fining agents in varying amounts that are known to reduce astringency. The four best fining agents to reduce astringency are all animal based: egg whites, gelatin, isinglass (from fish), and casein (from milk). Other commonly used fining agents include bentonite (a clay), Sparkolloid (from algae), and activated carbon. Keep in mind that fining is an optional tool, and if a wine is delicious as it is, it may not require fining at all.
So what's a vegan to do?
Generally, red wines are more likely (but not necessarily) to have been fined for astringency with an animal based product than white wines. Some red wines are bottled as "unfined" and these are really the only prudent choice for a strict vegan. White wines, too, are sometimes fined with casein or isinglass, so it is always recommended that vegans contact a winery directly to learn what wines are best suited to them.
Of the current releases of Rodney Strong Vineyards wines, vegans should be comfortable enjoying our 2007 Charlotte's Home Sauvignon Blanc, and our 2007 Sonoma County Chardonnay, both of which were finished only with "earth" based fining."