Thursday, July 7, 2011

Adverse Effects of Light & Heat on Beer


Recently I was asked the following question:

"Can a fridge that has got a white fluro tube in it, make the beer in glass go off?"

We sent the following reply and though it may be of interest to other readers.

The short answer is yes. The longer answer is that there are three big things that can alter a brews taste 1. Heat, 2. Light, 3. Time

There was a recent article in the 10th Issue of Beer and Brewer Magazine (Spring 2009) which discussed the science behind the effects of light in greater detail. We have included snippets of the article in the information below.

How does heat effect beer?

There is a good reason why brewers recommend beer is stored in a cool place. Heat can have a seriously adverse affect and even a short stint in a really hot car in summer has been known to change the taste of a brew for the worst. the taste of beer.

In Issue 10 of the B&B magazine it states:

"Heat will increase the oxidation rate of compounds in beer and produce a flavour and aroma that is often described as 'wet paper', 'cardboard' or 'sherry like'."

How does light effect beer?

From Issue 10 of B&B magazine:

"Exposure to light will produce offensive flavours and aromas that are described as 'catty', 'skunk-like' or 'lightstruck'."

Try to limit light exposure - including florescent light. Yes, even the lights in the bottle shop, bar fridges and your home fridge can have adverse effects. When beer is exposed to light it can cause a chemical reaction which transforms the acids in the beer and makes sulfur present. The presence of this sulphur is what spoils the beer and gives it the 'lightstruck' characteristics.

The ultimate way to eliminate 'lightstrike' is to only drink keg beer as no light can penetrate a metal keg. In the absence of being able to drink beer from a keg try to buy beers which are in brown bottles as brown bottles allow less light penetration compared to green bottles and significantly less compared to clear glass bottles.

Beer cans also reduce the effect of light, however, the vast majority of boutique/craft breweries don't use cans due to higher costs associated with the canning lines required (although these costs are reported to have come down in recent years) and the lower quality brand perceptions of beers which are canned.

How does time effect beer?

The majority of beers have a shelf life of around 9 - 12 months depending on how they are brewed and the style of beer. This is typically displayed by the 'Best before date' or 'Use by'date. Majority of beers are best consumed fresh, however, in saying this some beers are made with the purpose of cellaring and can be kept for a number of years. There are some beers in Belgium being sold at a pub called the Kulminator that are from the 1970's! Stored correctly, the right beer can be kept for years, e.g. stouts, strong ales, tripel and dubbel beers. Australian brewer, The Little Brewing Company, based in Port Macquarie NSW make a Strong Abbey Ale (8% ABV) which has a shelf life of a few years, if stored under proper conditions, i.e. cool and dark.

A rule of thumb: lagers are usually better fresher while ales can be savoured at a later date.

Also remember that when storing beer it should be kept upright. Why? An upright beer allows the yeast to fall to the bottom, in comparison, a beer stored on its side can allow a yeast ring to be created. It also reduces the surface area of beer which is exposed to air and prevents the risk of the beer obtaining 'off flavours' from the cork or crown.




About Beer Cartel:

Beer Cartel is an online beer store which specialises in the sale of boutique beer, beer gifts and beer appreciation in Australia. Its aim is to create an online community of beer lovers interested in experiencing craft beer from Australia and around the world. Beer Cartel also has a beer club which allows people to sample different beers from around the world.

http://www.beercartel.com.au



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