i have not had weevils in a number of years but I have recently had red flour beetles or confused flour beetles
they suck
what proportions do you use
For anything long term I pour the flour out onto long trays, let it reach 0°F/-18°C in my freezer and keeping it there for 3 days, then storing it in food safe 5-gallon buckets with bay leaves and oxygen absorbers, though some also use dry ice. [2]
weevils/beetles all absolutely suck.
[0] - https://www.tandfonline.com/doi/abs/10.1080/096708797229040?...
[1] - https://www.tandfonline.com/doi/abs/10.1080/096708799227950
[2] - https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=...
i'd be nervous about putting dry ice in a hermetically sealed container like a bucket
a thing i've noticed with storing food in plastic (pet) coke bottles is that they never seem to get beetles and that they tend to collapse a bit over the first year or so; i suspect that, even without a fe/nacl oxygen absorber, the food oxidizes enough to consume the oxygen initially present, which reduces the gas volume about 20 percent and kills any beetles initially present
my older notes on the topic are at https://dercuano.github.io/notes/food-storage.html
I only sift flour if I'm making scones, it seems to make a difference. I'm not a cakey person, I don't bake cakes. It's cake bakers that tend to care about sifting.