Wine storage and the cold chain in Indian heat

What wine wants

Wine keeps best somewhere cool, dark and steady. The figure usually quoted for long-term storage is around 10 to 15 °C, with 12 to 13 °C often called ideal. Stability matters as much as the number. A wine held at a steady 18 °C will usually fare better than one swinging between 12 °C at night and 30 °C by day.

Moderate humidity helps keep corks from drying out, which is why cork-sealed bottles meant for long storage are kept on their sides. Light is the other enemy. Ultraviolet light can cause off flavours, particularly in whites and sparkling wines in clear glass.

What heat does

Heat speeds up every chemical reaction in the bottle. A few weeks warm can age a fresh white by months. Fruit fades, colours brown and the wine starts to taste flat and stewed. Tasters call it cooked.

Severe heat does visible damage too. As the wine expands, it can push the cork up or seep past it, leaving a sticky trail under the capsule. Air then gets in and the wine oxidises. A pushed cork on a case is a strong sign that the whole case has been cooked, even if the label looks perfect.

In India, the summer months and parts of the supply chain that sit outside air conditioning are where this happens: a closed truck parked in the sun, a godown under a tin roof, a shop window facing the street. Inside a closed vehicle in May, temperatures can climb far above the outside air.

Where the chain breaks

Following a case from winery to customer shows the weak points:

• Dispatch and transport. Long road journeys between states, often in non-refrigerated trucks, with waits at checkposts or warehouses.
• Warehousing. Bonded and distributor warehouses vary widely. Some are temperature controlled. Many are not.
• Retail. Bottles standing upright under bright lights near a warm door, sometimes for months.
• Service. Reds served at Indian room temperature, which is well above the 14 to 18 °C they are made for.

The regulatory routes that govern this movement, such as transport permits and bonded storage, vary by state and change. They add time to the journey. Time is what heat needs. Our guide to excise for finance teams explains the process side.

What supply teams can control

• Season and timing. Plan big shipments outside the hottest weeks where possible. Avoid stock sitting at transfer points over weekends.
• Vehicles. Use refrigerated or insulated transport for premium wines and long routes. Even insulated pallet covers help on short hops.
• Warehouse standards. Ask distributors for temperature records, not assurances. A cheap data logger in a few cases will tell you more than any audit form.
• Stock rotation. First in, first out, with fresh whites and rosés moved fastest. Slow sellers in hot markets are a quality risk, not only a cash one.
• Retail guidance. Help outlets store bottles away from windows and lights. Store them on their sides if sealed with cork.

Reading the evidence in complaints

When a customer complains, the bottle often shows where it suffered. Pushed or leaking corks, brown colour in a young white and a flat, jammy taste point to heat. A musty, damp-cellar smell points to cork taint, which happens at the winery or cork supplier rather than in transit. Our guide to common wine faults covers how to tell them apart.

Tracking complaints by route, distributor and season usually makes the pattern obvious. If one distributor's region throws up most of the cooked-wine complaints every summer, the fix is in that warehouse, not the winery.

Screwcaps, bag-in-box and other packs

Screwcaps remove cork taint and leaks from upright storage. They do not protect against heat. Bag-in-box wines are convenient but are made to be drunk young, so they are even less tolerant of long, warm journeys. Sparkling wine adds one more risk. It is under pressure. A warm bottle opened at a launch event will gush half its contents across the table. Whatever the pack, the rule is the same. Keep it cool and dark, then keep it moving.