The smell of artificial butter is mostly butyric acid which is also the smell of Parmesan cheese, vomit and bee go, just in differing amounts.
I've always wondered if it's the smell of goldenrod or the smell of asters as they both always bloom at the same time here. But I smell gym socks. Some describe it as butterscotch. Part of it, I'm sure, is the subjectivity of smell, but some of it may also be the proportion of asters to goldenrod...
I'm the original poster here, and today, I noticed a sour-ish smell from my hive. Goldenrod is now in bloom, and the asters haven't really opened up yet. So, I am thinking, I've got the goldenrod stink. Maybe the asters will compound the smell when they really get blooming? The bees are bringing in some neon orange pollen and white pollen.