“it’s really ugly,” says Antonino Tranchida, head oenologist at Montalcino’s Col d’Orcia. He is referring to the blue-grey flakes that look like blades of wheat floating in a wine. The residue left by quercetin allows no euphemisms, in contrast to diamond-like tartaric crystals. It’s a relatively new phenomenon – and one that consumers notice. “There are worms in my wine,” was the complaint Montepulciano-based producer Salcheto received from US clients about its 2015 Obvius.