Combine the wine, vinegar and shallots in a sauce pan, preferably a saucier.
A saucier has sloping sides, making whisking easier and more efficient. Cook the mixture until a syrupy consistency is achieved.
On medium heat begin adding the butter, constantly whisking. When the butter is incorporated add the salt and peppers.
Taste the sauce. If too astringent add more butter and if too flat add a few drops of vinegar, (or lemon juice).
Adjust the salt and pepper to taste as well.
Pour over your cooked fish, vegetables, or more up my alley, a big juicy steak.