Of course it does.   Vermouth transforms chilled gin into a Martini!  Therefore it is indeed a magical liquid!

But what type of Vermouth?  Will just any do?  Is there a difference?

I’ve already written about the importance of keeping your chosen Vermouth chilled (Vermouth Storage?) and how much to add (How Dry Can You Go?).   This article discusses the impact of different Vermouths.

First of all lets get the sweet vs. dry Vermouth settled.  The original “traditional” martini calls for dry Vermouth.  All of my previous reviews and comments on Martinis have used dry Vermouth.  If you use sweet Vermouth then you’re making a ‘Sweet Martini’.  And there’s nothing wrong with that, if that’s your preference.

So, does it really matter which dry Vermouth?

I set up a little Martini taste test with a couple of popular and readily available Dry Vermouths:  Martini & Rossi (15% ABV), Noilly Prat (18% ABV), and Dolin (17.5% ABV).   The Martinis were prepared with New Amsterdam Gin.  This was chosen because it is pretty neutral with mild juniper and slightly on the sweet side. The proportions were 2 1/2 oz. Gin and 1/2 oz. Vermouth. For simplicity and consistency there was no garnish.

I then wrangled up a small team of amateur tasters to sample each of these Martinis.  I emphasize “Amateur”.  Initially some of the team were a bit dubious about the whole process, but eventually we all had a good time.  The team, self dubbed the “The Taste Buds“, tried each Vermouth in identical chilled Martinis and then by a few also tried the Vermouths neat at room temperature.

Each taster offered honest comments as they saw fit.  Some were comparative, some were impressions, some tried to discern individual flavors or aromas.  There isn’t any consistency, nor should there be.  The bottom line is, by unanimous agreement, that the different Vermouths affected the taste of the Martinis.

I asked each ‘Taste Bud’ to choose a first and second favorite Vermouth with 2 points awarded to a first choice and 1 point awarded to the second choice.  The ‘winner’ was Dolin, Matini & Rossi came in 2nd, and NP finished last.  For what it’s worth, I was the only who liked the Noilly Prat the best!

Only Vermouth Tasting Notes (room temp):
Dolin:  Spicy Aroma, Floral, Sweet, Earthy Front End, Little Spicy, Little Earthy, No aftertaste
Noilly Prat: Musty Aroma (port?), Lots of Grape, Bold, Spicy, Earthy, Bitter Finish, Neutral
Martini & Rossi:  Musty Aroma, Bitter Grape, Earthy, Citrusy, “most like white wine”
I made no attempt to attribute these comments to the tasters.

As a side comment, I personally sampled these Vermouths well chilled.  The only difference I noted from the room temperature tastings were that the chilled samples were less pungent.  As expected.

Conclusions: 
First, each of the sample Vermouths were individually different.  More so than I expected.  While they are all fortified wines with definite grape flavor, the method of fortification varies as does the underlying wine base.

Second, while the Vermouths were indeed different, everyone agreed that their impact on the overall taste of the Martini was minimal.  Discernible, yes, but the biggest impact to the taste of the Martini is, as it should be, the Gin!

Third, while minimal, the review team were unanimous in the opinion that the choice of Vermouth does change the taste of the Martini.  So, YES, your choice of Vermouth does matter.

Final though: 
It is definitely worth exploring different Vermouths, especially if you have a favorite Gin.  You might just find one that perfectly compliments your chosen Gin.