It’s common knowledge, less so now because we never need to do it. But go back in time and it’s common frontier knowledge, you can do this in a pinch. And in Medieval times, you can boil something in a pouch.
It’s just less reliable, the upper part hanging the bag could burn and you could lose everything. It’s just less durable. So anthropologists are likely to argue about how prevalent it was. Wouldn’t you want to transition to a more durable way as quickly as possible?
> Wouldn’t you want to transition to a more durable way as quickly as possible?
But what is durable? Pottery is fragile itself, and can break if you heat it too fast. I have not used either pottery or baskets on a fire so I can't comment myself, but I see no reason to think pottery is better. It probably depends partially on the society, if you are nomad hunter-gathers, pottery is heavy and breaks too easily, while farmers can just leave the pottery by where they cook and so it may be better.
It’s just less reliable, the upper part hanging the bag could burn and you could lose everything. It’s just less durable. So anthropologists are likely to argue about how prevalent it was. Wouldn’t you want to transition to a more durable way as quickly as possible?