For the Rhubarb Brandy:
Combine the chopped rhubarb and brandy in a container and tightly seal. Store in a cool, dark place, and shake daily for 3 to 5 days, until ready.
For the Rhubarb Vermouth:
Place the herbs and spices in a pan over medium-high heat and toast until very aromatic, tossing frequently so as not to burn. Add the wine and bring to a boil. Meanwhile, heat the sugar in a separate pan until it caramelizes; add it to the wine. Stir to dissolve, take off the heat, add the brandy and port, stir again, and let cool. Add the orange zest, pour into a container, and cover and store overnight in the refrigerator to infuse. Finely strain into a container, evenly distribute into glass bottles, and refrigerate.
To Assemble and Serve:
Mount ingredients in a mixing glass; add ice and stir. Strain into a cocktail or Old Fashioned glass over fresh ice and garnish with a lemon twist.