I watered this dose to one part absinthe to 4.5 parts water, without sugar.
The initial color in the bottle is red, deep like a vine ripened tomato, but transparent.
The louche is amazing, nice oil trails and opaqueness that comes out easily. At about 1:1 the color has shifted from red to more of an orange creamsicle. At 1:4.5 the louche is still alive and the color is more of a rosé peach.
Pre-water aroma is anise and fennel rich, with a lot of alcoholic heat. Once the dose was prepared the aroma was strong on the anise, with few of the other absinthe herbs coming through.
The flavor is very nice if you're into anise-heavy absinthes. There's plenty of wormwood flavor and some other bitter herbs as well, but sweetness and bitterness seem to be dancing together with this absinthe, alternating between the two. It's pleasant and very refreshing.
The finish is a little tart with notes of citrus, but not mouth puckeringly tart. There's some lingering wormwood and anise, but it i very muted on the finish.
I really like this absinthe, it's one of my top favorite absinthe, and certainly my favorite rouge out of the two others that I've tried, "Amerique Rouge" and "La Matriesse". In both brands, they were unpleasantly tart while the louche was picky and needed a lot of coaxing. Absenta Serpis though, is exactly what I had in mind for what an absinthe rouge should be. I was hopefull the final color would have retained more of the vibrant redness from how it looks fresh from the bottle, but that is a tiny thing for me to hold against such a wonderful absinthe.