Was using 1 gallon glass bottles for my main fermenter. Recipe used Sams honey, water and natural yeast on some raisins. Don't have the recipe in front of me, but it was high honey mix. Maybe a 1:1 dilution with water. But could have been a 1 : 2? Anyway, it was a high honey concentration.
It seemed to ferment OK in primary. After 15 months in gal jug it would not clear. I noticed the airlock had black mold in it. So decided it had enough time to work. Tasted the mix and it was sweet, but offered very little alcohol taste. Trashed it.
When cleaning out the glass jug, I rubbed around the inner neck of the bottle to clean out some of the reside. It was very greasy and would not wash off my fingers with water. Had to use lots of soap to cut the grease.
How can honey, water and some natural yeast make grease? I'm wondering if the Sams honey had adulterants in it?