Storing bulk olives – drum or barrel?

[paxwarder]

I've got a bit of a dilemma with my latest batch of cured olives from the family farm – last year I used these old metal barrels and they ended up rusting at the seams, which ruined about twenty kilos of perfectly good produce and I'm still kicking myself over it. I've been looking into food-grade plastic alternatives that won't leach any weird flavors or chemicals into the brine, and I found this open-top design that seems really practical for scooping out the olives without making a huge mess everywhere. I'm leaning toward trying out a 50 ltr drum because that size would be perfect for a single batch and the wide opening means I can easily check on the fermentation process without having to tip the whole thing over. Has anyone here used this kind of container for pickling or brining, and did you find the lid seals tightly enough to keep the fruit flies out during the hot months here? I just want to make sure I'm not repeating last year's disaster before I commit to buying a few of them.