Decide if you're making a flower wine (using sugar) or mead (using honey). The ingredients are the same for both, with the only difference being honey used in place of sugar for mead. For wine, you can add 4 to 6 cups of white grape juice in place of some of the water to help improve the wine’s body, though this is optional. Mead naturally has a fuller body, so grape juice isn't necessary. If you do use grape juice, reduce the sugar by about 1/2 to 1 cup.

Pour about half a gallon of water into a pot and bring it to a boil on the stove. Stir in the sugar or honey until fully dissolved. Let the mixture cool completely before moving to the next step.

Place the elderflower petals into the primary fermenter, then pour the cooled sugar water over them.

Add the remaining winemaking ingredients (except the yeast) and stir to combine.

Add cool water to the fermenter to nearly fill it. Mead will require a bit more water since there's no grape juice involved. Make sure the mixture is no hotter than 90°F, ideally around room temperature.

Once the mixture has cooled, dissolve the yeast packet in 1/4 to 1/2 cup of room-temperature water and let it rehydrate for 10 minutes. Add the yeast mixture to the fermenter. Refer to yeast recommendations in the notes.

Fill the fermenter with water (if needed) to reach the neck, then seal it with a rubber stopper and airlock. Let the wine ferment for 10 to 14 days until the fermentation slows (primary fermentation).

Once primary fermentation is complete, use a siphon to transfer the wine to a clean vessel, leaving the sediment behind. Remove the elderflowers at this stage and switch to a narrow-neck fermenter if you were using a wide-neck one. Re-seal with the airlock. For wine, allow it to ferment in secondary for 4 to 6 weeks. For mead, let it ferment for at least 4 months.

When fermentation is complete, bottle your wine or mead in wine bottles. Let the wine bottle-condition for at least 2 weeks, and wait at least 2 months for mead. While flip-top Grolsch-style bottles are fine for short-term storage, wine bottles are better for long-term storage (over 2-3 months).