IT’S been a long-held myth that Scotland’s beloved Irn-Bru tastes better from a glass bottle compared to plastic and cans.
And some reckon the nation’s ‘other national drink’ from McDonald’s is even better – despite coming from paper cups.
There’s a scientific reason behind why fizzy beverages taste better depending on how you drink them[/caption]
Dr Robert Barker explains the difference between plastic bottles, cans and glass[/caption]
And it turns out there’s a very scientific reason behind the difference – despite bosses at AG Barr using the same recipe whether it’s from a bottle or can.
We’ve spoke to food and packaging chemist from the University of Kent, Dr Robert Barker, who has finally sought to explain what REALLY causes fizzy drinks like Irn-Bru or Coke to taste differently depending on the vessel in which you drink them.
The immediate difference between glass, plastic, and a can is how strong they are at keeping those bubbles that make Irn-Bru taste so good locked in for longer.
Dr Barker said: “The carbonation of it will absorb over time into the inside of the plastic bottle which will reduce the carbonation over a period of time.
“Aluminium cans have an internal liner to them, so they usually have a resin which is put on the inside which is also essentially gas impermeable, so it means shelf life and loss of the carbonation is relatively low from a can as well.
“That means you get that tingling and that fizz when you open it and it feels kind of slightly fresher and lighter … the plastic bottle will lose [that] over time and naturally absorbs it.”
Another factor which can influence the taste from a plastic bottle is tiny amounts of material that can seep into the liquid over time.
These are not a cause for concern and are well below the levels allowed by the Food Standards Agency, Dr Barker explains.
He said: “It’s not dangerous but that could, particularly aldehydes, take a slight change in the flavour over time particularly if you’re talking about a bottle that’s right at the end of its shelf life and that certainly compares to glass which is again inert, so that flavour transfer is relatively low.”
A third important difference is how each material is able to keep cold – and once again, glass comes out on top.
Dr Barker added: “That means when we’re touching it to our lips and drinking from it, you get that extra cold taste from it that passes through. It touches our lips and probably improves our perception of it.
“Now cans are also quite good at doing that but not doing that for as long a period of time so they have quite a good transfer of coldness.”
Even the shape of the mouth at the top of an Irn-Bru bottle makes all the difference.
Plastic bottles usually have wider mouths on them compared to a glass bottle.
When taking a sip, we’re drinking “with our nose as much as our mouth” Dr Barker explained, so we’re getting all the sensations of the fizz, the smell and everything else from a much smaller space, alongside the enhanced chill factor mentioned previously.
Why does it taste even better from McDonald’s?
Some Irn-Bru lovers believe McDonald’s serves up the best drink despite the fact it comes from a basic paper cup.
And there may be a very simple reason for that.
Dr Baker suspects the perception of what you’re eating and drinking may be the main reason why Irn-Bru from McDonald’s tastes good.
Some fans believe the fizzy drink tastes better at McDonald’s[/caption]
But he says the way fountain drinks work may have an influence too.
“The drink is pressurised and delivered more immediately,” he explained.
“So it’s delivering a taste that’s more imminent as opposed to something that’s sat on the shelf, gone through a supply chain in a different way.
“They’re essentially able to deliver a product which is closer to their original design without having to rely on shelf life.”
Dr Robert Barker is a food and packaging expert[/caption]
