I made shrub, the slow way, with a cup of strawberries, a cup of sugar, a cup of water, and a cup of vinegar, as (I think, if I understood the recipe) directed here for cold-process shrub. Turned out great. But now, I find what looks like a mother of vinegar floating around in the bottom. Has anyone else experienced this? Is it a problem? A blessing? Should I remove it, or just leave it to its ghostly little routine?