So my suspicions are aroused when she sets down two clinking glasses that sparkle in the low rays from the first sun we've seen in three days at Portavadie, and says. "They asked if I wanted Hendricks. But it's expensive. I said their own brand was fine."
Then she blinks twice and looks away.
"Good thinking," I tell her, lifting the cool drink to my lips and savouring the tang of citrus, juniper and quinine that bursts fresh from the most popular drink in the galaxy. "Our holiday kitty is getting low and all gin tastes the same anyway."
"You don't half talk bollocks at times," she says, gazing at the bars of pink cloud above the wind-rippled waters of Loch Fyne.
"Not at all," I tell her. "Malt whisky is by far the most complex distilled spirit. Everybody knows that. A good malt has hundreds of subtle aromas, with their origins in the water, the air, the cask, the peat and the intricate chemistry of ageing.
"Vodka and gin are just raw alcohol for people with soft brains who want to get pissed by following fashion and knocking back kiddy drinks called cruiser, breezer, bruiser, greaser, soft screw, kiss mix and mudshake."
She refuses to be clinched. "Forget vodka," she says. "There is more to gin than you realise, pal. Your problem is you don't listen. You just go off on one. So you'll never learn any more than you know now."
"But that's loads," I tell her. "If I put more in it'll shove important stuff out, like how to drink beer and put my socks on. When I was young my brain was like a Dyson, sucking up great swathes of science and philosophy."
"But it blew a fuse long ago," she says. "Because it hoovered up too much half-chewed gum and balls of fluff. You need to get those out and more good stuff in."
"Go on then," I sigh. "Tell me about gin."
She takes a long sip through the black, bendy straw favoured by big girls and poseurs, brushes a bumblebee away with the back of her hand and says, "Gin is a fairly modern drink.
"But it comes from jenever, a traditional Dutch tipple flavoured with juniper berries and botanicals - a secret mix of herbs and spices. British soldiers are supposed to have drunk jenever for its calming effect before battle, which is where the term Dutch courage comes from."
"Shut up and listen, Stephen," she tells me.
"Hendricks is a modern gin made in Scotland in a traditional way," she says. "They use two old stills bought at auction, which produce very different styles of spirit that they blend together. Besides the botanicals and aromatic juniper, they also use essence of cucumber and rose petal. The result is the 'best gin in the world', according to the Wall Street Journal."
"Well if I believed all that, I might have been tempted to get myself one and just say I'd bought the cheap stuff," I tell her.
She blinks twice and looks away.
"You sneaky rat," I say and she smiles, sips her Hendricks and studies the sunset.
"I like holidays," she tells me.