Problems with Rose-infused Liqueur
So I am trying to make rose-infused liqueur...
I combined 750ml of grain alcohol with one cup of dried rose flower and allowed to steep for ~1 month with occasional agitation. This was in turn double-filtered through paper coffee filters and a simple syrup solution was added to sweeten the mix and take the gravity down to about 64 proof.
This was placed into clean 0.25/0.5L swing top bottles. At the time of bottling I would have described the appearance as a red-brown with good amounts of clarity. Most of the bottles I just put in the cupboard, but one went directly into the freezer as prior experience indicates these things taste better chilled.
Fast forward one week. When examining the bottles prior to tasting, a semi-thick green film had accumulated at the fill/liquid line. To a varying degree, it exists in all the bottles, including the one put in the freezer. This would seem unlikely to be a bottle cleanliness issue. Moreover, how could a mold grow: (a) in alcohol, (b) in the freezer?
There is a touch of green on the dried flowers (the "dried leaves", I suppose). But how could this particulate escape filtering?
I smelled and tasted it (for science!) Not really sure how it is supposed to taste, but nothing seemed terribly "off", nor have I died yet.
Any ideas on what might be going on here, or how to clean up the mess so that it might be suitable for gifting? Re-filtering is a possibility, but I'm afraid the sugared liquid would never get through a fine coffee filter...
Dried rose petals were acquired from an Asian grocer.
I photographed one of the bottles that was not immediately frozen. When flipped upside down notice that there is lots of particulate and the "mold" is so thick that it blocks the liquid from flowing into the neck of the bottle (a little shaking is enough to break this and the green stuff quickly blends in with the remainder).