Today we associate pasteurisation mainly with milk, but the technique was originally developed to stop wine and beer from spoiling.
While the principle of boiling liquids to kill microbes was nothing new – even if people didn’t fully understand why it worked – it was in 1864 that French biologist and chemist Louis Pasteur realised the same effect could be achieved just by heating the wine to a high temperature. Unlike boiling, pasteurisation didn’t result in a loss of flavour.
Since refrigeration techniques have come a long way since the 1860s, pasteurisation is not always necessary for some products such as beer, but since an Act of Parliament in 1922, most milk in the UK has been pasteurised. Generally this means either heating the milk to 71.7°C for 15 seconds, or just a second at a sweltering 135°C for UHT milk. This applies to both dairy and plant-based milks, but there are some purists out there who can’t stand the heat and insist on drinking “raw” milk.