Old house - sweet smell after rain

I live in a 100+ year old house that my husband and I have been slowly remodeling. I have noticed the same sweet smell after 2 separate unrelated water events. The first occurred several years ago when a slow water leak in an upstairs bathroom caused a sweet smell in the kitchen the cause of which went undetected until the leak suddenly erupted and the kitchen ceiling caved in. The smell was extremely strong after the water, plaster, old wallpaper, drywall etc. came down.

The current smell problem started during an ice damn event in our gutters this past winter. Water made its way into the house and down the upstairs and downstairs walls to terminate by dripping through the light fixtures in the kitchen. I have noticed the same smell in the kitchen and upper rooms since then, especially after it rains. We have repaired the roof, gutters, flashing, and the masonry, including a chimney above where the event occurred to try to address any problems that may be allowing water to come in. We have torn out large parts of the kitchen ceiling in search of obvious water, mold, etc. We have also crawled into the attic space in search of these things. The masonry work was just completed last week and now a new rain storm has brought the smell back.

I am without a clue as to what to do next. We really want to fix the kitchen but are afraid we will be covering a problem.

Maybe try to get an experienced inspector in to find sources of moisture.
Could almost be worse, at least it's not a rancid smell prior to finding a leak or sewage backing up in your tub. There's always a way to stay on the bright side of an issue.

If you know a real-estate agent, they'll know plenty of home inspectors. Some are very thorough, some aren't, but the agents know who's who.