I have simple tastes in tea. A cup of builders’. I detest herbal tea, unlike my partner, Ed, who likes peppermint. Before the return of the twentysomethings, there was one glass storage jar of English breakfast in the kitchen, and a box of peppermint for Ed. And that was how we liked it.

Twins Megan and Lily’s arrival has changed all that because they have brought tea with them. A bewildering variety in brightly coloured boxes. They are always dunking bags of sawdust into hot water and rhapsodising over the benefits of the resulting bilious liquid. Different herbs, they say, have wonderful effects on everything from period pains to bad skin to libido, although some have to be drunk under a full moon. I’m not paying for this dubious cult, I tell them, so they will have to buy their own tea.

Not long after, I find Ed muttering to himself in the kitchen. “Did you forget peppermint?” he asks.

“It’s here,” I exclaim, wondering why he can never see what’s right in front of him. I yank open the cupboard and have to drop to my knees to catch an avalanche of boxes that comes tumbling out. Ginger, camomile, basil and cinnamon teas fall into my arms.

“Could you keep your boxes of tea somewhere else?” I ask my daughters. “And don’t drink the peppermint.”

“There’s no space in our rooms as it is,” Lily objects. “We can’t start keeping food in them too.”

All that caffeine’s not good for you, Mum. Especially at your age. You should try drinking some herbs

I see her point. We live in an old house with no storage space. I don’t know where the Victorians kept their stuff. They certainly didn’t have kidults returning and cramming guitars, vintage clothes, boots, computers, desks, retro turntables, stacks of vinyl and dumb-bells into the tiny top rooms.

“Well, you’ve taken over my shelf,” I tell her. “I’ve got nowhere to put my coffee or the hot chocolate. There’s nothing but undrinkable tea in it now.”

Lily rolls her eyes. “All that caffeine’s not good for you, Mum. Especially at your age. You should try drinking some herbs.”

“Yes,” adds Megan. “There are loads of teas that are good for menopause.”

“I’ll make you some Earth Mama,” Lily suggests.

I decline, brewing myself a strong English breakfast, heaping in sugar to make a point.

To drink their copious amounts of herbal tea, the girls use mugs the size of small buckets. Both of them seem to have at least two mugs on the go at the same time, which they leave by the kettle for refills, not wanting to “waste washing-up”. This results in the entire surface being taken over by gigantic, stained ceramic mugs that leave rings on the wood.

I have put all the mugs in the dishwasher and am baking in my kitchen, which is empty, apart from me and the cat. The radio is on quietly. I open the cupboard where the flour is stored to find that I can’t get at it because there are several boxes of tea in the way. I pull out a bag of Wormwood brew that looks like something else, although I smell it, and it isn’t. I cram it back, extract the flour and continue.

Needing a spatula, I try to open a drawer, only to discover a box of rooibos stuck in the runner. I rip it out, scattering teabags on the floor. It’s like the Boston Tea Party all over again. There might not be 342 chests going overboard, but I am certainly feeling oppressed.

I keep my temper, remembering I am the real adult here, and my daughters have little experience of housekeeping.

“You keep buying new packets and not finishing the old ones,” I explain to them later. “You can’t drink them all at the same time. You need a system. Some discipline.”

Megan is already peering inside the cupboard, and Lily joins her. How eager they are to learn, I think. They are taking things out and tut-tutting.

“Look,” Lily says to her sister. “Mum’s system. Three bags of rice, all open. Five bags of penne, nearly empty. This one’s only got three bits of pasta in it.”

Megan snorts, holding up a tin of chestnuts: “Use-by date, March 2008.”

“Oh, for God’s sake,” I snap. “Stop ganging up on me.”

I switch on the kettle and reach for the builders’.

Some names have been changed

• The Stranger by Saskia Sarginson (Piatkus, £7.99). To order a copy for £6.79, go to bookshop.theguardian.com or call the Guardian Bookshop on 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min. p&p of £1.99.