Which is the reason you don't want to use paper bags either. I'm not sure what "hessian" translates to out here in the colonies, but we use burlap bags... loosley knit ones made from a hemp type material... but, as scotman intimates, keeping them in the dark is important. We have huge commercial potato storage units here in the western U.S. and the temperature is maintained at a constant 42 degrees (F)... so... obviously cooler is better as well...
My dad was an avid gardener and grew fantastic potatos. He always stored them in double layer, brown bags. The same type that farmers use when they sell sacks of potatos. I would have though hessian could let damp in which isn`t good.
a hessian bag is ideal because its breathable.
keep in a dark place ad critically inspect them every week.
i do this and on each occasion have fond the odd one starting to rot.
if left this process can quickly affect your spuds.
good luck