Magnums & Ageing: Why magnums age More Gracefully

They say size matters — and in the world of wine, it certainly does.

They say size matters, which is undoubtedly true in the world of wine. With its impressive 1.5 litre capacity, a magnum is a perfect size for a gathering of 4 – 6 people, and it looks undeniably celebratory sitting on the table, outshining its ubiquitous bottle-sized sibling.

Nothing beats a magnum when making a statement at a dinner party. Yet its magic goes beyond presentation — there’s science behind why magnums age better.

So why does a magnum evolve more slowly and elegantly than a standard 750 ml bottle? Here’s the story behind size, oxygen, science — and flavour.

Let's start at the beginning

Why 750ml Became Standard — and Where Magnums Fit In

One theory is that it was the largest size that early glassblowers could produce with a single breath. It took some serious lung power to create a bottle back in the day.

Fast-forward, and we now have an entire family of large format bottles, particularly for Champagne, Chardonnay and Pinot Noir — from Magnum, Jeroboam, Rehoboam, Methuselah, Salmanazar, Balthazar, Nebuchadnezzar, Solomon, Sovereign (a newer size), Primat and Melchizedek. All have biblical origins and go from the 1.5 litre magnum up to a dizzying 30 litres, even 40 litres (my kind of bottle).

In reds, especially those rooted in Bordeaux tradition, we see a similar hierarchy: Magnum → Double Magnum → Jeroboam → Imperial, and so on. The most oversized format ever produced was the Maximus, a staggering 130 litres of which you could pour 1200 glasses.

Why Magnums Age Better

Magnums sit at the ideal size-to-oxygen ratio for ageing wine.

Filling these larger, more unwieldy formats can be challenging. While magnums can

be filled and sparged with gas just like a standard bottle on the bottling line, bottles more

substantial than a magnum must be decanted from smaller bottles to fill them up. This

process makes them more susceptible to oxygen ingress and affects their ageing ability

compared to magnums or standard bottles.

Magnums are ideal because they have:

• Same neck size and cork as a 750ml bottle

• Same ullage (oxygen headspace) inside

• Double the volume of wine

  
  

Because oxygen exposure is proportionately lower in a magnum, chemical reactions responsible for ageing occur more slowly. Wines retain freshness, fruit purity and brightness for longer, and complexity builds gradually rather than racing toward maturity.

Magnums & Autolysis in Champagne — More Bubbles, More Complexity

Speaking of ageing and using Champagne in a magnum bottle to give perspective, one can observe that the larger glass surface area in a magnum allows for greater contact between the yeast cells lining the inside of the bottle and the wine during autolysis, when yeast breaks down and imparts flavour and mouthfeel to the wine. This gradual breakdown of yeast gives Champagne its effervescence and works better in a magnum because of its greater surface area, creating more bubbles. This results in magnums displaying much more roundness as the wine ages and, crucially, much more complexity. This is due to the carbon dioxide in sparkling wine, which acts as a preservative, helping to keep it fresher.

Before expanding on the magnums per se, it is worth touching on the ageing process. READ HERE FOR MORE.

The Ageing process in magnums vs standard sized bottles

Magnums are large enough to slow down the ageing process. The wine stays younger and fresher for longer than in a 750 ml bottle; this has been proven consistently over many tastings.

There are a few variables other than the bottle itself which will affect the maturation process;

• Wine storage (maturation) conditions

• Cork or screwcap

• Whether or not the wine has been fined or filtered

Returning to the bottle size.

1. The smaller the bottle size, the faster its contents will mature.

   It is generally believed that the smaller the bottle size, the faster

   its contents will mature. This is because the bottle has a more significant proportion of

   oxygen. This is a consequence of bottling and, importantly, any oxygen ingress via the cork seal during ageing. If we extrapolate upwards, a bottle will mature more slowly than a half-bottle, whilst a magnum will mature even more slowly.

2. The ratio of wine to oxygen is higher in a magnum.

   The reactions that encompass ageing will take place more slowly and arguably in a more dignified fashion, whereby the complexities

   and the wine's flavours are teased out gradually and with greater grace.

3. The necks of 750 ml bottles and magnums, and thus the cork's dimensions, are usually the same. Therefore, the ullage in that headspace is identical, and it would follow that a magnum would age at half the speed of a bottle.

   If we continue up the format sizes, double magnums or Jeroboams tend to have specialised larger corks, and the bottles have wider necks, thus allowing for far more oxygen to be trapped between liquid and cork. So perhaps a magnum is the golden ratio!

4. Larger format bottles are made with thicker, heavier glass.

   This is to protect them from wine's major enemies: heat, light and travel-

   related vibrations. Most large-format bottle options are dark green instead of clear glass, which helps keep out harmful light. This thicker glass also helps with cellaring and regulating the wine's temperature, as it takes longer for ambient heat or cold winter temperatures to penetrate. Vibration, such as during wine transportation, can also damage wine, and the thick, heavy glass absorbs more shocks than thin glass used for 750ml wines.

One can agree or disagree with the claim that magnums tend to age better. But one cannot dispute that empty magnums make excellent lamps, candleholders, and vases, as well as any other Pinterest-approved bottle crafts and creative home décor projects. And besides, watching your friends pick up a heavy, empty bottle and try to pour from it

never gets old.

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