Have you ever walked into a bar and noticed the temperature display on beer fridges showing -4°C? Would you believe that this is just a marketing trick?

How do we know this?

Most beers (which range from 4-6ABV%) will generally freeze at around -2ºC, and we also know that as soon as liquid begins to freeze, it will expand and crack glass bottles. Therefore, any colder than this, it will just freeze and pop the bottle. So we can safely assume that the beer is not exactly that cold!

Over the past few years, breweries have been on the competitive edge to come out with something new, great and wonderful ways to promote their products. Not too long ago, Castle Lite introduced a two-stage indicator on their bottle labels which changes to a dark blue when the “optimum” temperature is reached. Of course, other breweries caught on to this and followed this idea too.

Because we have been accustomed to associating cold temperatures with the best beer drinking experience, marketing departments figured out new ways to sell this perception even further by enhancing our senses. This is why beer fridges have large temperature displays, added to this, ever noticed that beer kegs are deliberately frozen or dripping with water? It just plays with our senses to enhance the craving for an ice-cold beer.

Although it’s not very efficient to freeze the beer taps this way because extra energy is needed to keep the taps cool, the trade-off is to just sell more products!

Now back to why the fridge shows -4°C.

On average, beers should remain at around 3-4°C, Castle light, however, is the only beer lagered at 2.5 °C and the clean crisp taste is best when served at sub-zero temperatures. (This is starting to sound like an advert), nevertheless, to give you the perception that you are drinking a cold brew is to fiddle about with the temperature display.

Although they are not lying to you by showing -4°C, what they are not telling you is that this is the temperature reading on the evaporator, not the fridge cabin, and certainly not the product. Added to this, we have to also wonder why the marketing team decided to make the display so large and obvious because it sells the product!

But why specifically -4°C?

To keep a fridge cool requires energy which is used to draw heat out of a refrigerator. To keep a happy medium between efficiency and marketing, the evaporator used for these specific refrigerators generally freezes off at around -4°C (instead of est. -9°C as most other fridges), which is also why beer fridges generally take longer to chill. Also if they did peak the fridge off at -9°C and show it on their display, it would be too obvious.