One of the tips you come across regularly in the more learned cocktail guides and resources is to keep opened bottles of vermouth in the fridge to prevent them spoiling, and to not keep them around for too long no matter where they are stored. Unfortunately vermouth, though fortified and far more shelf-stable than wine, is fairly low in alcohol content (usually around the 18% mark) and will slowly degrade over days and weeks if left at room temperature.
At least that’s what I have always been told. I’ve always taken this advice as fact and not really given it much though, but tonight I found myself unusually well prepared with brand new bottles of dry and sweet vermouth to replace my rapidly emptying old bottles so decided to see if I could really taste a difference. You’ll notice both brands have had their bottles redesigned recently – perhaps a sign vermouth is gaining in popularity and worthy of a re-brand, but then again maybe an attempt to modernise a sadly underrated category of spirits.
Noilly Prat dry is my standard dry vermouth, and this bottle has probably been sat in the fridge for perhaps three months, though it could be anything up to six. The new bottle is brand new, opened tonight, and sports the new design that Noilly Prat appear to have rolled out at some point in the past month or two. To keep things fair, I stuck the new bottle in the fridge last night so they’re both at the exact same temperature.
I was surprised that soon as I poured the two vermouths I could see a noticeable difference even in the colour. The older bottle had a slight copper tint to it, compared the the light straw colour of the new one. The nose was also quite different, with the older bottle having a fairly smooth, mildly aromatic aroma. This contrasted with the fairly sharp, fragrant nose of the fresh vermouth.
In the mouth the old vermouth continued the mellowness from the nose, and had a slightly sweet fruity tang. The finish was mildly bitter and the overall taste fairly one-dimensional. The new bottle had a much drier, more intense flavour that was more overtly fruity and with a floral undertone, and the finish had a more defined bitterness. Overall the old bottle had definitely changed in character quite a lot, and while it hadn’t gone bad as such it would definitely have an effect on cocktails made with it.
Unfortunately while some are lucky enough to build their own basement bar I reside in the second most expensive city in the world and as such am stuck sharing a kitchen, and hence refrigerator, with several friends for the foreseeable future. My fridge space is therefore limited, and so I have to choose which bottles of cocktail goodness reside there carefully. My bottle of Martini & Rossi sweet vermouth unfortunately didn’t make the cut, so has been sat out at room temperature for a good six months since I first opened it.
With the differences in the Noilly Prat after around three months in a fridge I was expecting six months on the shelf to have a noticeable effect, but when pouring out the two samples there was no difference between the two, at least visually. On the nose too there was little to tell the two apart, both having a mellow, fruity aroma.
When it came to tasting the new bottle did have a fuller, more intense flavour, but unlike the Noilly Prat where the flavour profile had altered, the Martini & Rossi had merely mellowed. The same flavours were there, they were just more subdued. Given the age of the old bottle I was surprised at this, though also pleased as it means I can let my sweet vermouth sit out on the shelf without too much worry.
Overall then, confirmation of knowledge I already practise. Dry vermouth is relatively unstable, so should be used quickly and/or refrigerated once opened. Sweet vermouth fairs better, but does still dull so shouldn’t be kept around too long. Given the low-cost of vermouth it is thankfully affordable to keep bottle around for 3-6 months and dispose of once faded.
I just wish smaller, more easily finished bottles were readily available. Here in the UK a lot of supermarkets only sell 1 litre bottles of vermouth, and given how long these often sit in peoples alcohol cabinets, that makes for a lot of imperfect vermouth…
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