Vodka

Aiming for neutral is not the same as arriving there. Vodkas differ in weight on the tongue, in sweetness, in how much heat they carry at the back and in whether the finish stays clean or turns slightly bitter. Those differences are small next to the gap between two whiskies, but here they are the whole story. Taste it neat and at room temperature if you want to find them, because ice and mixer flatten every one of them out.

Vodka can be made from almost any fermentable crop. Grain, usually wheat or rye, is the most common and tends to read as crisp with a touch of pepper. Potato gives a rounder, creamier body. Grape and sugar cane bases turn up as well and often taste faintly sweeter. Distilling to very high strength narrows all of those differences considerably, which is rather the point of the exercise, so the base named on the label is a hint rather than a promise. Two vodkas from the same crop, made by different producers, can still land in quite different places.

Charcoal filtration pulls out compounds that read as harsh or oily, and it is why many vodkas taste softer than their strength suggests. It is a subtractive step, so it cannot put in anything that was not already there. A claim about the number of filtration passes describes a process rather than a result. The more useful test is whether the spirit sits comfortably on the tongue without burning.

It will not freeze at normal domestic temperatures, so nothing is harmed by it. Cold thickens the texture and mutes both the aroma and any rough edges, which is why a freezer bottle pours so smoothly. The trade-off is that it also hides whatever character the vodka has. Keep an everyday bottle cold for mixed drinks, and let a more interesting one sit at room temperature.

A martini is mostly spirit, so there is nowhere to hide. Look for enough body that it feels like a drink rather than cold water, and a finish that does not turn bitter as the glass warms.

Sealed and out of direct sun it is effectively stable, since there is no fruit, sugar or wood in it to change over time. Flavoured vodkas are the exception, because the added flavouring fades well before the spirit does.