The short answer to this question can be found on the question page How long does vermouth keep after opening?. Below you can read the whole story behind it.
Of the 31 vermouths on our shelves in Bathmen, nine carry the word rosso, six the word dry and three the word bianco. They stand side by side with the gin and the whisky, and that is precisely where things go wrong at home.
Because a bottle of vermouth looks like a spirit, but it behaves like wine. An opened bottle of gin can be left for a year. An opened bottle of vermouth cannot.
Vermouth is wine, not a spirit
Vermouth belongs to the aromatised wines. The base is ordinary wine, usually a neutral white, supplemented with herbs and a dash of alcohol to bring the whole to strength. European rules require it to contain wormwood, the herb of the genus Artemisia, and the end result to come out between 14.5 and 22 per cent alcohol.
That wormwood is also where the name comes from. Wermut is the German word for it, and via French that became vermouth.
In practice this means only one thing. At fifteen to eighteen percent alcohol, the alcohol does not preserve. In a forty-percent whisky hardly anything can happen in the bottle; in a vermouth, oxygen can simply do its work, exactly as in a bottle of wine.
Dry, bianco or rosso: the difference is in the sugar
The designations on the label are not style names that a house invents itself. They stand for sugar levels and are laid down.
- Extra dry: less than 30 grams of sugar per litre.
- Dry: less than 50 grams.
- Medium dry: 50 to 90 grams.
- Medium sweet: 90 to 130 grams.
- Sweet: more than 130 grams. Most rossos and biancos fall under this.
That difference in sugar is about taste, but it also determines how well the bottle keeps. A dry vermouth is pale, light in body and has little to hide behind. If it deteriorates, you notice straight away.
A rosso is full of sugar, caramel and heavier herbs. These mask the first changes, making it seem usable for longer than it is. It goes flat just the same, only less visibly.
How long does an opened bottle stay good
There is no legal time limit, and the houses themselves are cautious about it. As a rule of thumb, behind the counter we use the following, provided the bottle is kept in the fridge:
- Extra dry and dry: at its best in the first month, acceptable up to about two months.
- Bianco and blanc: about two months.
- Rosso and rouge: two to three months.
If the bottle is kept outside the fridge, in an ordinary kitchen cupboard, you can roughly halve those periods. If it stands next to the cooker or in the sun, it goes even faster.
Compare that with spirits. An opened bottle of jenever or rum is still fine after a year. Vermouth is much more a relative of port in that respect, and even port keeps longer after opening than vermouth, because port is more highly fortified. We wrote about that earlier in how long port stays good after opening.
How you can tell it is past its peak
First look at the colour. A dry vermouth that has gone from straw yellow to golden brown has seen air. With a rosso this does not help, because it is dark already.
Then smell it. A fresh vermouth smells herbal and fresh at the same time. A bottle that has been open too long smells flat and heads towards apple skin or nut. That is the same oxidation you get in an opened bottle of white wine.
Taste last. If it turns bitter without anything fruity or herbal underneath, the bottle is finished. That is not dangerous, but it is no longer enjoyable either.
What helps and what doesn’t
What helps: put the bottle upright in the fridge, put the cap on immediately, and do not leave it standing on the counter between two drinks. Standing cold slows oxidation more than anything else.
Something else that helps: decanting into a smaller bottle. If the bottle is half empty, pour the rest into a smaller bottle that you fill to the brim. Less air above the liquid means less oxygen to react with.
What doesn't help: buying a one-litre bottle because it works out cheaper per litre. If you mix a drink once a month, half a litre or a small bottle is smarter. Then you finish it while it is still what it should be.
And if a bottle is past its peak after all: in the kitchen it is still perfectly fine. Nobody notices a splash in a pan with chicken, cream or mussels.
Where to start
If you mainly make martinis, a small bottle of dry vermouth serves you better than a large one. If you make a negroni or an americano, you use rosso and a regular bottle will do, because more of it goes into each glass.
Six of our bottles carry the designation Vermouth di Torino. That is a protected name: that vermouth must be made in Piedmont and based on Italian wine. It says nothing about shelf life, but something about origin.
If you are unsure which bottle suits the way you drink, walk in or call 0570 541 278. We will honestly tell you how soon you should drink it.
Keep browsing
The full vermouth stock is on our vermouth page, and with the shop search you can browse everything. Houses we stock include Martini, Noilly Prat, Dolin, Carpano and Cinzano.
What vermouth is exactly and where it comes from is explained on our page what is vermouth. For a fortified wine that does keep well after opening, see ruby or tawny port.
