HEALDSBURG, Calif. - Some of the last remaining areas to have power restored were farmland, including Sonoma and Napa County vineyards.
The PG&E shutdown came at a precarious time: harvest.
"Grapes can start to shrivel, then sugar gets too high and wine quality goes down," said vineyard manager Mark Houser of Alexander Valley Vineyards.
Crush pads across wine country have been humming since August, with grapes moving from field to fermenting and eventually to barrels and bottles, but Wednesday after midnight, that stopped.
"Three full days of cold showers and no coffee," said Houser, "so bad for the grapes and bad for me too!"
The AVV property is on the original homestead of Cyrus Alexander, who founded the Alexander Valley in the early 1800's.
More than two dozen wineries call it home, and most were forced to leave their grapes hanging on the vine during the blackout.
Fermenting tanks already full of juice can't be emptied to make room for more, because pumps rely on electricity.
"Getting power will be a big relief," said Houser, "so we can drain the tanks, press off the skins and hopefully next week start up picking again."
As Wednesday afternoon stretched on, staff at AVV started to hear of other wineries getting their power back.
"We're thinking we're going to be next, we're going to be next," said enologist Tony Jacques, checking the tanks, worried that juice wasn't moist and circulating for optimum color and flavor.
That process also depends on pumps, which weren't working.
And since fermentation generates heat, the tanks, when operable, also keep the contents cool.
"With no power that means no circulation of the coolant around the tanks, so we are doing what we can to keep the temperature moderate, sometimes with dry ice," said Jacques.
Fortunately, the fire-safety shutdown was not accompanied by a heat wave.
Grapes might not have weathered it well, because irrigation systems depend on electricity too.
"I actually was having nightmares that there was a fire and we had no water to put it out because there was no electricity to run the pumps," said Harry Wetzel IV, Family Partner and Operations Manager at AVV.
Finally, just before 6 pm Friday, power came back on, in time for the tasting room to reopen this weekend.
Wetzel says the uncertainty of the intentional shutdown made the ordeal even more difficult.
"I heard it was going to be 24 hours to 6 days, so anything in that range, and 6 days would have been disastrous."
Going forward, winemakers are likely to look at generators in a new light.
Some managed to rent one in time for the shutdown, but generally only the largest vintners have full backup power system.
They can cost a few hundred thousand dollars and installation is complex, with permits, plumbing and wiring possibly running another $100,000.
"We always have to adapt to whatever nature throws our way," said Houser, noting that outages from wildfire, or wildfire risk, are a new challenge.
"Harvest coincides with fire season so we're going to learn to get through it, that's the tough part and the lesson."