https://en.wikipedia.org/wiki/Moisture_sensitivity_level https://en.wikipedia.org/wiki/Moisture_sensitivity_level If you order parts from a major distributor (

https://en.wikipedia.org/wiki/Moisture_sensitivity_level https://en.wikipedia.org/wiki/Moisture_sensitivity_level If you order parts from a major distributor (arrow, avnet, digikey, mouser, etc.), everything comes with appropriate humidity indicators where needed. Pretty much anything that is something + plastic around it will be affected to some extent. I haven't seen things go "popcorn", but broken off edges and cracks across a package... yeah. Add: that said, moisture from a blowtorch probably won't have such an effect; you need to get it nice and deep into the package and unable to come back out. Add(2): this is also why ziplock bags make good outer semiconductor packaging. Make sure you properly zip them back up whenever possible. Add(3): a quick look through my semiconductor stack (SMT ICs, mostly QFN, some SOP, no BGAs) is about 30% MSL3, 45% MSL2 and 25% MSL1 or unmarked.