What you need 500 ml of cream 2 tbsp of live yoghurt or buttermilk A cheesecloth
Have you been using time stuck indoors to master homemade bread? The next step is to make your own butter. Or if you havent got into bread, maybe start with butter its actually much easier and the result is much tastier than the shop-bought variety.
A century ago, butter was made by leaving milk out in big vats until cream formed on top. This took a few days and the cream would ferment, thanks to bacteria that metabolise lactose to produce lactic acid. The same types of microbes are involved in making kimchi and sourdough bread. Apart from acid, the bacteria produce a range of aroma compounds that make for a more richly flavoured butter.
The key molecules include buttery diacetyl, cheesy butanoic acid and peachy delta-decalactone. Diacetyl is added to many foods to add butter flavour. It is also present in some alcoholic drinks, and may help to create the buttery flavour of wines like chardonnay.
In milk and cream, the fat is contained within globules coated with a membrane, which allows the fat to remain suspended in water as an emulsion. To make butter, cream is churned, which ruptures the fat globules, allowing the fat inside them to stick together and form a solid mass.
Most butter is now made from pasteurised cream using machines that separate the cream quickly, without live bacteria having a chance to add to the flavour. Some restaurants make their own cultured butter, and its easy to do at home, using a source of lactic acid bacteria, such as from buttermilk or live yoghurt.
Mix 500 millilitres of cream with 2 tablespoons of yoghurt or buttermilk and leave in a covered container at room temperature for at least a day. It will thicken and smell tangy at first, then more pungent, but dont worry most of the smell will be in the liquid that gets separated out. Leaving the cream for up to a week gives the butter a slightly cheesy flavour.
Before churning, chill the cream to 14 °C so that the butter will be solid, but not so firm that it sticks to the sides of the mixer. Process in a food processor until the butter separates from the buttermilk this should take up to 3 minutes.
Line a sieve with cheesecloth over a bowl and pour in the butter mixture. Wrap the cloth around the butter, squeeze and twist to press out liquid, stopping when butter starts to come through. Dunk the cloth-wrapped butter in a bowl of ice water to chill it for a few minutes, then tip the butter into a large bowl and knead with a wooden spoon to press out any remaining buttermilk and pour away. If desired, add salt, then put in a clean container.
The tangy buttermilk can be used to make pancakes, salad dressings or buttermilk-marinated roast chicken.
newscientist.com, 7 May 2020