For what it is worth, Maxwell Farms, my family's Maple Syrup farm up in Vermont, ships me a half gallon each year on Xmas, and it is in a plastic jug.
I doubt the container is an indication of quality. In fact fraudulent maple syrup is often in glass containers, to make it look more expensive.
If you have ever seen maple syrup production, it usually uses a lot of ten gallon plastic drums. I doubt there is anything in plastic that hurts the syrup or in glass that helps them.
BTW There was a discussion among my cousins when the Farm switched from tin cans to plastic bottles. The plastic won, as it was something like a quarter a set cheaper than the tin cans for a half gallon. I think everyone thought that they were neutral in quality, some thought the tin was more traditional, but cost won out.
I'd just look, whatever the packaging, to the ingredient list. If it has corn syrup it is ungood.
Vermont, I'm told, and Canada are devising a voluntary seal for pure maple, they have been debating about it for years, I suspect our grandchildren will see it. Maple syrup farmers tend to be ornery taciturn northmen. It is like herding cats if the cats were already pissed off.
sourdough isn't a recipe, it is a process.