Handy hack: Just blow on a bottle of Baileys Liqueur to see how much is left

Rather than peering inside or estimating by the weight, drinkers can now measure the contents by blowing across the top of the bottle to make a note.

The liqueur brand has designed an online tool for smartphones, which will listen to the pitch and calculate the volume of liquid left.

You might think it would be easier to simply change the colour of the glass – but the bottle’s shade actually helps to protect the drink from excess light.

The Sound Scales technology works on the principle that the deeper the pitch of the bottleneck note, the more air there is and the less liquid there is.

Baileys was created in 1971 by mixing whiskey from the Gilbeys of Ireland distillery and surplus cream from Express Dairies – both were owned by the same company.

The thick, creamy consistency can wreak havoc on the pipes by clogging up the U-bend and stopping other liquid from passing through.