A breadbox -- basically a foot-square container with an opening that's not airtight -- creates a controlled environment somewhere between those extremes. The moisture from the bread raises the humidity in the box, but air circulation keeps it from getting as moist as in a sealed plastic bag.

Does a bread box need ventilation?

Your primary goal when choosing a bread box should be to find a product that will keep your loaves of bread and baked goods fresh. For optimal ventilation, the bread box must contain air vents or holes. Proper airflow and moisture levels will help keep the bread soft while also preventing it from getting moldy.

Should a bread bin be airtight?

The open pores of an earthenware container will absorb excess moisture and even return moisture to the bread when it begins to dry out. ... Bins without an airtight seal, which allow air to circulate, offer similar advantages, and bread will also remain relatively fresh for a good length of time in a wax-coated bread bag.