Cognac glasses

Start with the capacity, because it says more than the shape. The glasses here run from 15 cl to almost 89 cl, and that difference is not about pouring more. A generous balloon such as the Schott Zwiesel Bar Special of 88 cl gives the vapour plenty of surface to gather on, so you mainly smell the volatile top layer. A more compact glass of 25 to 45 cl, such as the Royal Leerdam Gilde or the RCR Timeless, keeps the aroma closer to the liquid and lets the heavier wood notes come through better.

Then mind the rim. The more sharply it turns inward, the more alcohol vapour is concentrated. That is pleasant with a young cognac, but it quickly makes an old XO too sharp. A tulip shape with a slight opening, found at Chef & Sommelier and Zwiesel Glas, gives that sharpness room to drift away.

Finally, look at the stem. A short stem lets you cradle the glass in your palm, a longer stem keeps your hand away from the liquid.

Pour no more than three to four centilitres, however large the glass. In a 70 cl balloon that means a thin layer on the bottom, and that is exactly the point: the rest of the glass is there for the air. Tilt the glass and swirl it round once gently so the wall gets wet, wait half a minute and then nose it with your mouth slightly open.

Warming cognac over a small flame is a habit from the sixties that you hardly ever see in France any more. The warmth of your hand is enough. If you would rather taste it cooler, the tulip glass works better, because you hold that by the stem.

Cognac in a cocktail calls for a different glass. A sidecar goes in a coupe, and you build the champagne cocktail with a dash of cognac over a sugar cube in a flute.

Most cognac glasses in this collection are made of lead-free crystal glass, a material that stays clear and can be blown thin without breaking straight away. Zwiesel Glas and Schott Zwiesel use a tempered variant that copes with thousands of dishwasher cycles, while the toughened glass from Arcoroc is made precisely for the rush of a bar kitchen.

Large balloons rarely fit well in a standard basket. Set them at an angle between the prongs so the rim does not knock against anything, because that is where almost every breakage starts. Dry them afterwards with a linen cloth rather than cotton, as it sheds less lint. Limescale on the wall comes off with a splash of cleaning vinegar in lukewarm water, followed by a brief rinse with clean water.

If you are looking for something for whisky rather than cognac, you are better off with the whisky glasses, where the emphasis is on tumblers and nosing glasses that are wider and lower. For grappa, calvados and eau de vie, the smaller bowls at grappa glasses and port glasses make more sense. If you want to put the bottle itself on the table nicely, look at the carafes. And if you are going to mix cognac rather than pour it neat, you measure the proportions precisely with a jigger.