Oxidizing

Beer – like most products – is negatively impacted by age. With each week in the bottle, chemical changes are happening which affect the flavour of your favourite brew.

There is a consensus amongst many that beer is – for lack of a better word – indestructible. Sure, it may have been thrown around, shaken-up, warmed-then-cooled-again, but its beer right? It will surely still taste like beer?

If only….

The presence of oxygen in the bottle results in a number of chemical reactions – and unfortunately the process is mostly inevitable. No matter how cautious you are, no matter how effective the brewing set-up, oxygenation of your beer will occur.

A brewer from Malt Shovel once said to me: “We are the lucky ones. We get to taste beer at its very best, the day it is brewed. What we need to consider is that everyone else buys the beer in a different state, and we want to try to keep the quality for them.”

When you consider that the average six-pack in a bottle shop is 13 weeks old (three months), and that most beers have a designated nine-month shelf-life, it’s a phenomenon to be aware of, and something that brewers are endlessly working on.

There is some serious science behind oxidizing, but I will try to keep it in layman’s terms – for your benefit and mine. Basically, molecules in the beer can undergo chemical reactions with oxygen that cause changes in flavour. Different compounds are formed which result in different flavour changers – some more noticeable than others, but all definitely affecting the flavour of your favourite beer.

Trans-2-nomenal causes a papery flavour in the beer. 2.3-pentanedione causes honey-like aromas to sneak in. Diacetyl results in buttery and butterscotch flavours and is caused by yeast metabolism.

Which brings me to one of the more recent entries on my beer bucket list.

An Italian brewer has intentionally oxidized one of their beers – usually a severe faux pas in brewing – to deliberately add the sherry-like flavours that come with it: Birra Baladin’s Xyauyù line.

As noted by the brewery, “Xyauyù is a living, top-fermented beer which – after being exposed to the air of the Langhe area and resting for a long period of time – becomes a new and unique product.”

The beer is allowed to oxidize during the two-and-a-half year aging process (a staggeringly long process for a beer). Too much oxidizing will ruin the flavour, whilst too little will not optimize the chance. It’s a delicate process. The system works by-storing the beer in a steel vessel with a transparent membrane and oxygen hat.

One might question why the beer is simply not made using sherry, or aged in sherry barrels. One best mind their own motherflippin’ business – all good brewers take their experimentation one or three steps past what is required, and I won’t have anyone question the – I imagine – good folk at Birra Baladin.

To counter your logic, I give you the following: The Xyauyù Barrel. A beer which has gone through macro-oxidation and has been aged in oak rum barrels. When poured, it has no head and no gas.

Cool right?

I know not when I will be in Italy next, nor how I would go about tracking down such a beer. However, I do have a very particular set of skills, skills I have acquired over a very long career. Skills that make me a nightmare for beers like you. I will look for you, I will find you, and I will drink you…

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