How did they make buttermilk in the 18th century?

In the 18th century, buttermilk was typically a byproduct of churning cream into butter. After the cream was whipped, the remaining liquid was strained off, resulting in buttermilk. This tangy, slightly sour liquid was often used in baking, cooking, or as a drink. Additionally, some households might have soured fresh milk intentionally by adding vinegar or lemon juice to achieve a similar product.