Kerning (or ‘kerned’) refers to an ancientSomerset term for ‘thickening’ predominantly used in relation to dairy products. The word has historically been used to refer to the processes around curdling.,[1] churning,[2] coagulating[3] or thickening milk, and its origins have been thought to be linked to the verb, ‘to churn’ - which translates to ‘kernen’ in German, ‘karnen’ in Dutch and ‘kirna’ in Old Icelandic[4]
The word has since been adopted as a synonym to the straining/filtering processes involved in thickening yogurt – the phrase ‘kerned yogurt’ being used to identify products which have been subject to these processes. In correlation with the word’s links to Somerset, ‘kerning’ as a process is used throughout Somersetshire, as a means of producing yogurts with a distinctively thicker consistency.
Traditionally, the kerning process involved placing the yogurt in a muslin cloth and leaving this to drain for a period of time, until the desired consistency had been reached;[5] however, modern-day practises useultrafiltration to achievethis result . In addition to increasing the consistency, the process serves to boost the protein and also remove some of the lactose (the sugar found naturally in milk).