Hmmm, would it actually be twine? I'm thinking some sort of plant stalk, straw if you could tie it or bind it. (I'd guess straw's too brittle but it'd be readily availability if you're producing grain.)
I'm thinking, it doesn't have to be very strong, and if you can't reuse the twine anyway...
There would have been very little gluten in that bread - look at the rise. Additionally, something about soughdough reduces the effect of the gluten on those that are intolerant. Don’t take that as medical advice though...
I'm thinking, it doesn't have to be very strong, and if you can't reuse the twine anyway...