Fill a glass jar with chopped rose petals and elder flowers.
In a glass jar, pour vinegar over the rose petals and elder flowers, filling the jar to the top with vinegar. Make sure that the vinegar covers the herbs by at least a couple of inches.
If you’re using a metal lid, cover the opening of the jar with two sheets of wax/greaseproof paper to avoid corrosion, and then put the lid on (or use a plastic lid).
Store vinegar in a cool dark place for one month to infuse. Shake it once in a while and occasionally check to see if you need to add more vinegar, as some of it may have been soaked up by the herbs. Add more vinegar if the herbs are sticking out above the vinegar.
Place a funnel into the opening of a clean, sterilized jar and lay muslin over the top of the funnel.
Pour the infused vinegar through the cloth and funnel into the clean jar.
Discard the strained liquid ingredients into the compost. The liquid left behind is your herbal vinegar.
Stir the rose hydrosol into the strained herbal vinegar.
Using a funnel, pour the mixture into a clean, sterilized dark glass spray bottle.
Store in the refrigerator and use within 2 to 3 months for the best quality.