Floor of aluminum container used as a cheese cave collapsed.

Repurposing a shipping container—especially a reefer container with a T-bar or flat aluminium floor—into a cheese cave is common, but the environmental conditions of cheese ripening are highly aggressive toward aluminium.

Aluminium relies on a microscopic, protective oxide layer to prevent rust. In a cheese cave, several factors will systematically destroy this layer and deteriorate the floor.

1. Salt and Brines (Chloride Pitting)

This is often the fastest-acting culprit. Whether from direct brine spills, cheese dripping onto the floor after salting, or salt carried in tracking boots, chloride ions are highly destructive to aluminium. They penetrate the protective oxide layer, causing deep, localized “pitting” corrosion that turns the smooth metal into a rough, porous, structural hazard.

2. High Humidity and Ammonia Gas

As cheeses ripen—especially washed-rind or bloomy-rind varieties—they release significant amounts of ammonia gas.

• A cheese cave requires an ultra-high relative humidity (often 80% to 95%).
• When ammonia gas dissolves into the airborne moisture and condensation on the floor, it forms ammonium hydroxide, an alkaline solution.
• Aluminium is an amphoteric metal, meaning it corrodes in both highly acidic and highly alkaline environments. Constant exposure to this alkaline moisture will slowly dissolve the floor.

3. Acidic Whey and Lactic Acid

Dripping whey contains lactic acid. While aluminium handles mild organic acids better than it handles harsh mineral acids, continuous pooling of warm, acidic whey in the grooves of a container floor will gradually etch the metal and worsen existing pits.

4. Harsh Cleaning Chemicals

Using traditional dairy-plant cleaners on an aluminium container floor will ruin it rapidly:

• Caustic Soda (Sodium Hydroxide): Commonly used to strip organic soils and fats in dairies, it aggressively attacks aluminium, dissolving it with a fizzing reaction that releases hydrogen gas.
• Chlorine Bleach (Sodium Hypochlorite): Combines severe alkalinity with high chloride content—a worst-case scenario for aluminium.

5. Galvanic Corrosion (Mixed Metals)

If you place stainless steel ageing racks, copper drain fittings, or mild steel brackets directly onto the wet aluminium floor, you create a battery cell. In the presence of high humidity and salty moisture, the aluminium acts as a sacrificial anode and corrodes at an accelerated rate where the metals touch.

How to Protect the Floor

? Recommendation: If you want the container to last, you must create a barrier between the room’s atmosphere and the bare metal.

• Epoxy or Polyurethane Coating: Thoroughly clean, etch, and prime the aluminium using a specialised metal primer, then apply a heavy-duty, food-grade seamless epoxy or polyurea floor coating. Ensure it curves up the walls slightly (a coved edge) to prevent liquids from pooling in corners.
• Isolate Equipment: Use heavy-duty plastic or rubber pads under the feet of all stainless steel or metal shelving units to break the electrical contact and prevent galvanic corrosion.
• Sloped Drainage: Ensure the container has a slight tilt toward a dedicated plastic or high-grade stainless drain so that washing water, brine, and whey can never sit and pool on the floor.

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