What's the purpose of a bread box?

In my experience, they're best at concentrating mold spores, and hiding away unsightly loaves.

While chic, and quite popular in the days before plastic bags, they're not much use now. Pretty much the same as the "pie safe"

A bread box is intended to keep bread fresh. The materials don't matter that much.

A bread box keeps bread fresh by trapping moisture to prevent the bread from drying out. The tighter the seal on the bread box, the better it performs this function.

Additional Reading:

• http://www.wisegeek.com/what-is-a-bread-box.htm
• http://en.wikipedia.org/wiki/Breadbox

The wikipedia article about breadboxes states:

They were a more common household kitchen item until bread started being made commercially with food preservatives and wrapped in plastic. Breadboxes are still used by many people to store commercially purchased bread, but are used more especially by people who bake bread at home.

And that they also

protect their contents from mice and other pests.

They're intended to provide a cool, controlled place to keep the bread away from direct sunlight and most pests, to reduce the rate of moisture loss, and reduce the likelihood of the bread getting moldy.

I'd personally avoid metal in areas with high temperature swings (daily, not yearly) because I'd be concerned with changes in temperature outside causing condensation inside the box. If you have air conditioning and don't have it cycle on/off during the day, this likely isn't an issue.

Some people don't actually like the wooden bread boxes, because the smell of the wood used can transfer to the bread. It's possible that the nature of the wood, if it were unsealed, might help to regulate the humidity of the box (absorb a little if it's too high, give a little back if it's too low), but from what I recall (and it's been more than 15 years since I've used one), all of the ones we had were vented, so I don't know how much this is actually an issue. (it's possible that not all are vented -- in looking online, some of the metal ones claim to be air-tight ... I'm not sure how I feel about that).

Don't keep your bread in the fridge, for goodness' sake. You lose a lot of flavor and freshness by doing that. It speeds decomposition of certain aspects of the bread even if it does make it last longer. A bread box is meant to be used to keep bread fresh and great tasting for 3-6 days, which is about the longest you can expect fresh bread to last. There is a balance of powers happening within that box and the balance is not to be messed with.

There is ventilation and moisture retention. The ventilation comes from the small intentional gaps in the bread box. The moisture comes from the bread. That moist environment is fine because you want to have moist bread. Too much moisture isn't good either—which is why if you live in a moist climate you should get a large bread box and don't overstuff it. The more bread in the box, the more moisture in the box. If you live in a dry climate you could probably get away with a loaf, several bagels, and a few buns and not have any trouble but in a moist environment, that's asking for trouble.

If you have trouble with humidity then a breadbox is probably not that helpful - you'll probably want to keep your bread in the fridge. But the fridge actually makes bread go stale faster, so if you're in a fairly dry area a bread box can be very useful for keeping bread fresh. I think it's more effective than just tightly sealing the plastic bags, but I haven't done any studies.

Also I personally like it for corralling my bread products (loafs of bread, buns, bagels, etc.) so they're not just strewn about the kitchen. It also contains crumbs, and I find it easier to clean than a pantry shelf, since you can just hold the box over a trash and shake. They're also useful for any snacks you like to keep easily accessible, since those can be make an otherwise clean kitchen look messy.

Were I live. A bread box is used to put a slice of bread in. In less than 15 minutes this will draw ants. Once the bread is covered in ants. You spray inside the box to keep there numbers down. Even putting bread in sealed plastic ones the ants will find a way in. This is tropical use of them.. Way up north. When women baked bread once a week. It was put in a bread box to keep moist for the week. It slowed bread from drying out. In today's world the plastic bag it comes in does a better job of keeping bread fresh. So they are more just for looks. In the old days some use to add a slice of apple or such to the bread box to keep bread moist. So they were the bread wrapper before bread wrappers came about. In the tropics ants just eat a hole threw the wrapper. Why we have a small bakery in each neighborhood. Ants don't attack hot ovens.

Bread boxes were actually made to keep fresh bread that didnt come pre pavkaged in plastic, much like 90% of store bought bread today.. Id say 1950s & before most bread came from bakerys, some came in a paper bag, others like baguette breads were bought with no wrapper. It was best to remove the paper because paper attracts moisture. The bread box was kept in a cool not cold like a refrigerator, but cool, dry and dark place. Daily you should open the box just to remove moiature & then close the box back up. Most baked breads then didn't have all the preservatives that todays food is loaded with. So without a bread box a fresh baked loaf was best the 1st day baked. When stored in the breqd box this could extend the life 2 to 3 days longer. I was born in 1960 & have had a bread box on the counter every day of my life. Ive found even with todays pre packaged breads in plastic, even though filled with preservatives to help leep it fresh for approx 7 to 10 days, which is what ive come to see with moat all breads today, that the pre packaged breads will stay fresher and mold free when kept in a bread box, again in a cool dry and dark location. No need to open the plastic surrounding the bread, this doesnt seem to help with todays breads wrapped in plastic. I hope this info helps. I will add by putting breads in a refrigerator, this will attract moisture and breads dont need excess moisture, the fridge & its cold will ruin bread very quickly. You can freeze breads, but i reccommend for no more then about a month. Since 99% of bread has moisture, a freezer will keep it for extended periods, but if too long a time it will make bread extremely dry and brittle...