From the first glass to the last

Plenty of us store wine carefully: a wine fridge set to the degree, a cool cupboard, a cellar. Then the bottle comes out, the first glass is poured, and it starts to drift. Within half an hour a white that was right is soft and flat, and a red that was right is warm and heavy.

Getting wine to temperature is the easy part. Keeping it there is where most of the care is lost.

Why the temperature slips

An open bottle on the table heads toward the temperature of the room. A glass heads there faster, because it holds so little. Indoors, wine in a glass warms by roughly a degree every few minutes. Outdoors in summer, faster still.

So "chilled" at the first pour rarely lasts past the second. The question isn't only what temperature to serve at. It's how to hold that temperature while the bottle is open.

The usual answers, honestly

Back in the fridge between pours. This works for temperature, but it takes the bottle away from the table, and a domestic fridge at 4–5 °C cools most wines past their best. Fine for a weeknight glass; awkward at a dinner.

The ice bucket. It's reliable and it looks generous, but it has one setting: as cold as it can get. Ice and water pull a bottle toward 0 °C and keep going. That suits a simple sparkling wine on a hot day. It flattens a good white, and it's no help for a red that should sit at 15 °C. It's also wet: the label soaks, the bottle drips across the tablecloth, and someone has to keep fetching ice.

The sleeve or chilled jacket. It's tidy and dry, and it buys you some time. But it's warming from the moment it leaves the freezer, and it has no control at all.

The cellar or wine fridge. It keeps storage and serving temperature perfectly, but only as long as the bottle stays inside.

Each of these either cools without stopping, or lets the wine warm without limit. None of them lets you choose a number and keep it.

Holding a number

That gap is why we built the GRAD No.1. It's a rechargeable wine cooler that holds a bottle at a temperature you set, anywhere from 5 to 20 °C, to the degree. Champagne at 7 °C, a white Burgundy at 11 °C, a Pinot Noir at 13 °C, a Barolo at 15 °C. Each at its own number, through the whole bottle.

It works with a solid-state thermoelectric system, with no ice and no water, so it's quiet enough for a dinner table and leaves the label dry. It runs on its battery wherever the evening goes (the table, the terrace, the boat), and it keeps cooling while it sits on its charging plate.

What to know before you rely on it

We'd rather you knew the details up front.

• Start with a chilled bottle. The GRAD No.1 is built to hold a temperature, not to chill a warm bottle quickly. Bring the wine close to its band first, and let the cooler keep it there.
• Battery life depends on the number you set. In a 22 °C room it runs about 4 hours at 5 °C, 9 hours at 10 °C and up to 20 hours at 15 °C. Warmer surroundings or direct sun shorten that. A full charge takes 2.5 hours.
• Bottles up to 10 cm across. That covers standard wine and champagne bottles. Some unusually wide bottles won't fit.

The small detail that makes the evening

The wine you open for a dinner was grown, made and cellared with care. Keeping it at the right temperature to the last glass is a small thing, but it's the difference between tasting the wine properly for one glass and for the whole bottle.