First, a lidded crock isnt airless, thats a lot of air still
under the lid, Anerobic bacteria find oxygen counterproductive
to having big families. Canned environments for example, are
perfect, cozy breeding grounds.
Did you ever ask your husband what it tasted like?
Any off flavors? Bitteness? Any alcoholic taste at all?
My money is on spontaneous fermentation by wild yeast in the
air, and given your description of ingredients, especially things
like honey and the low,...