I recently had the opportunity to visit Hunter Bottling, a wine bottling company in the Hunter Valley, where owner Russell Smith kindly walked me through every stage, from the production line to the lab. It was a reminder that while we often focus on vineyards and cellars, the final stage of bottling quietly determines how a wine will be experienced by the consumer.

How Does Wine Move from Tank to Bottle?

Wines arrive at the facility in large transport tanks, often travelling from nearby wineries. Once delivered, they rest onsite for two to three days under carefully controlled temperatures. This allows the wine to stabilise before the bottling run begins.

Before a single bottle is filled, the onsite lab checks essential parameters such as pH, titratable acidity (TA), alcohol, and both free and total SO₂ (which help protect wine from spoilage and oxidation). If any parameter falls outside specification, the winery is immediately notified so adjustments can be made before bottling. These checks ensure that the wine’s composition is sound and stable before it meets glass.

Clean Glass, Clean Wine

The hot water at 86°C is used for sanitising the machines and filters, usually for 30 minutes, keeping the entire bottling line safe and hygienic. Before bottling, the wine undergoes a final sterile filtration to ensure no bacteria or yeast remain, even if it has already been filtered at the winery. Clarity and microbiological stability are essential to protect the wine’s integrity. Even though the bottles are brand new and shipped from South Australia, they are rinsed with fresh sterile water just before filling.

To further protect against oxidation, an inert gas such as carbon dioxide or nitrogen is flushed through the bottles before filling. This process displaces oxygen, reducing the chance of spoilage and helping wines stay fresh for longer.

Precision at Every Stage

The line is capable of processing up to 36,000 bottles per day and can handle every bottle size, from half bottles to magnums. Closures are tailored to winery preference, including screwcaps, corks, or even corks with wax-dipped tops if requested. The corks themselves are sourced from Portugal, a country known for its long tradition of cork production.

Once the bottles are filled, dissolved oxygen in the wine is measured. The target is around 0.5 ppm, which is low enough to protect freshness without introducing a reductive character. Quality control continues even after bottling. Bottled samples from each order are sent to the lab three times for full analysis, including pH, TA, alcohol, and SO₂ levels.

More Than Just the End Point

Watching this process made it clear that bottling is not just a logistical step. It is a delicate handoff. The decisions made at this stage preserve the winemaker’s vision all the way to the consumer’s glass. From sterile bottles to controlled oxygen levels, every small detail plays a role in protecting the final wine.

Final Sip

Walking the bottling line in the Hunter Valley made me appreciate the unseen craftsmanship behind every bottle. It is not only the vineyard and winery that shape a wine’s journey. It is also the precision, care, and quiet discipline of the bottling process. A special thanks to Russell Smith for opening the doors and sharing the careful detail that goes into sealing a story inside each glass bottle.