When it comes to finding a substitute for sweet vermouth, there are a few options that can provide a similar flavor profile. One popular choice is Lillet, a French aperitif wine that has a sweet and fruity taste. Lillet Blanc, in particular, has citrus and floral notes with a hint of bitterness, making it a suitable alternative for sweet vermouth in cocktails like the Negroni.
Another option is Sherry, a fortified wine from Spain. Sherry comes in various styles, ranging from dry to sweet, and can be a great substitute depending on the type you choose. For a closer match to sweet vermouth, Pedro Ximénez (PX) Sherry or a sweeter style like Cream Sherry can work well. These Sherries have a rich and syrupy texture with flavors of raisins, caramel, and dried fruits, which can add depth and sweetness to your cocktails.
Personally, I have found that Lillet Rouge, the red version of Lillet, can be an excellent choice when seeking a more robust and flavorful alternative to sweet vermouth. It has a deeper, more pronounced fruitiness with a touch of spice, making it a great addition to cocktails that require a bolder profile.
In terms of using dry vermouth as a substitute, it's important to note that it will result in a different flavor profile. Dry vermouth has a lighter and less sweet taste compared to its sweet counterpart. However, this can be advantageous for certain cocktails, such as the Contessa, where a brighter and more herbaceous flavor is desired.
When looking for a substitute for sweet vermouth, Lillet, Sherry (particularly PX or Cream), and even dry vermouth can all provide interesting alternatives depending on the specific cocktail and flavor profile you're aiming for. The choice ultimately comes down to personal preference and experimentation to find the perfect substitute that suits your taste.