Thistle rennet is a natural coagulant derived from the flowers of certain thistle plants, particularly the Cardoon thistle. It is used in cheese-making to curdle milk, helping to separate the solid curds from the liquid whey. This process is essential for producing various types of cheese. Unlike animal rennet, which comes from the stomachs of young ruminants, thistle rennet is a vegetarian alternative. It is often favored by those seeking plant-based options in cheese production. Thistle rennet can impart unique flavors to cheese, making it a popular choice among artisanal cheese makers.