Load and space

Metal wins, clearly. Steel or iron carries far more load per unit of material than wood, so a metal rack holds the same bottles in thinner sections — more capacity in the same footprint, or the same capacity in something visually lighter.

The construction method matters more than the material here, and it is the specification most buyers overlook. The Sorbus metal wall rack is welded rather than bolted, which means its joints cannot work loose as the load shifts. Bolted racks — in any material — can, and a rack that loosens while holding glass on a wall is the failure you do not want. Where a listing states welded construction, that is worth more than any finish.

Humidity, which only affects one of them

Wood is hygroscopic: it takes up and gives off moisture with the air around it, and it moves as it does. In a stable interior room that movement is invisible and irrelevant. In a damp basement, a garage or an unheated outbuilding, it is not — joints loosen over years, finishes lift, and in genuinely damp conditions untreated wood can develop mold.

Metal does not care about humidity in the same way. It can corrode in wet conditions, but a powder-coated or painted steel rack in a normal basement will simply sit there. So: damp or unconditioned space, choose metal. This matters most for exactly the rooms that are otherwise ideal for wine — basements are cool and stable and often humid. What humidity does to the wine itself is a separate question, covered in wine fridge humidity.

What happens to your labels

The trade-off nobody mentions, and the reason wood persists in a category where metal is mechanically better.

Bare metal is harder than glass and much harder than paper. Slide a bottle in and out of a metal cradle a few dozen times and the label scuffs — a real irritation on bottles you are keeping, and worse on anything whose label you care about. Wood is softer and cradles the bottle over a wider contact area, so it is gentler. Coated or padded metal racks narrow the gap, but bare iron does not.

So the rule of thumb: bottles that move constantly favor wood; bottles that sit still favor metal. A countertop rotation rack in metal is fine, because those bottles get opened. A long-term rack holding wine you will move in and out over years has a case for wood.

Deciding

Wood or metal, by situation
Your situationChooseWhy
Maximum bottles in minimum spaceMetalMore load per unit of material, thinner sections
Wall-mountedMetal, welded if possibleLoad concentrated at fixings; welded joints cannot loosen
A damp basement or unconditioned roomMetalWood moves with humidity; metal does not
The rack is furniture in a living spaceWoodReads warmer; the mahogany set looks like joinery, not shelving
Bottles in and out constantlyWoodSofter, wider contact area — kinder to labels
A countertop rotation rackEitherThese bottles get opened; label wear is irrelevant

And one thing neither material changes: a rack of any kind inherits the room’s climate. If the room is the problem, the material is not the answer — rack vs fridge is the page you want.