Short answer: In German, “Lab” refers to rennet, an enzyme used to coagulate milk in cheese making. The term covers both animal-derived rennet and microbial (microbiell) or vegetable alternatives, depending on the source. Details

• What Lab is
• Lab is a mixture of enzymes, mainly chymosin (also called rennin) and pepsin, that causes milk proteins (casein) to coagulate, turning milk into curds for cheese production. It can come from the stomachs of young ruminants (animal/vegetal origin) or be produced by microbes as a substitute.

• Types of Lab
• Animal lab (tierisches Lab): Traditionally sourced from the fourth stomach of calves and other young ruminants; used to coagulate milk without acidifying it.

• Microbial lab (mikrobielles Lab): Produced by microbial fermentation and used as a vegetarian/vegan-friendly alternative; does not involve animal slaughter in its production.

• Uses in cheese
• Rennet enzymes cause milk to thicken and separate into curds and whey, enabling cheese formation. Different cheeses may use animal or microbial lab depending on the recipe and regulatory standards.

Notes

• Lab has ancient recognition for its ability to curdle milk, with historical references to its coagulating power in early cheese making.

• If you need to know whether a specific cheese uses animal or microbial lab, check the product label or the producer’s information, as practices vary by cheese and region.