Christmas crossword 2023: solutions and winners

Thanks to everyone who took part in the 2023 competition—there were quite a few entries, so I apologize for the delay in announcing the results. 

As in the past, there were one or two clues that, with hindsight, might have been more carefully constructed. The main difference from what I had in mind appeared in 21 down, Opera biscuit? (6) where I carelessly took this for granted:
Packet of Jacob's Mikado biscuits
but I acknowledge that Figaro is a valid answer too. Thanks for letting me know that the puzzle gave some entertainment and amusement—we may even do it all again next year. In the meantime, you'll find the completed grid and solutions below. 

Vouchers are on their way by e-mail for all worthy efforts received, and the bottle of André Clouet's fine Grande Réserve champagne, awarded to the first correct entry out of the (digitally randomizing) hat, goes to Anita Mathur. Congratulations!

 Completed grid for Bubble Brothers Christmas crossword 2023

ACROSS

  • 1 Vine berry (5)
  • GRAPE
  • 4 Strengthened, like port, sherry or Madeira (9)
  • FORTIFIED
  • 9 Gin berry (7)
  • JUNIPER
  • 10 How many sleeps till Christmas, on the 17th (5)
  • EIGHT
  • 11 One of five starts an appellation in the Loire Valley (6)
  • QUINCY
  • 12 Some Beaujolais, on the 16th November, 2023 (7)
  • NOUVEAU
  • 14 It’s baking in here (4)
  • OVEN
  • 15 A socialist pulse in the soup? (3, 6)
  • RED LENTIL
  • 19 Sparkling red wine from northern Italy (9)
  • LAMBRUSCO
  • 20 Ladies’ fingers are all right next to the Royal Academy (4)
  • OKRA
  • 22 Marvel, wonder (2, 2, 3)
  • BE IN AWE
  • 25 Rías ______, wine region in Galicia (6)
  • BAIXAS
  • 27 Singer loses head, but makes rule after reshuffle (5)
  • REIGN
  • 28 Let slip origin in time—a job for a plumber (7)
  • LEAKAGE
  • 29 A roomful of stretchers (4, 5)
  • YOGA CLASS
  • 30 Band from the watering hole? (5)
  • OASIS

DOWN

  • 1 I-jog-backwards berry (4)
  • GOJI
  • 2 How the Romans sometimes banqueted—in their own words (2, 7)
  • AD NAUSEAM
  • 3 Spain, as they say in Spain (6)
  • ESPANA
  • 4 Brettanomyces can make your wine smell like these (9)
  • FARMYARDS
  • 5 Greeting card favourite hasn’t given up on twitter (5)
  • ROBIN
  • 6 Square, square, square—yet as cool as can be (3, 5)
  • ICE CUBES
  • 7 Mingle topless where the heat is on (5)
  • INGLE
  • 8 Information transfer, to the cloud, perhaps (4, 6)
  • DATA UPLOAD
  • 13 Festive fruit sounds like a film star (5, 5)
  • HOLLY BERRY
  • 16 Seasonal ding-dongs, often with a guest appearance (9)
  • DOORBELLS
  • 17 Stay awake in confusion for fast food (9)
  • TAKEAWAYS
  • 18 Runnymede agreement distilled into brandy—no ta!
  • ARMAGNAC
  • 21 Opera biscuit? (6)
  • MIKADO
  • 23 In the choir, me? Sounds like it (5)
  • ICING
  • 24 Has a walk-on part, something above and beyond (5)
  • EXTRA
  • 26 More than one Cork river may enrich your wine (4)
  • LEES