Discovering Queijo de Manteiga cheese from Brazil
Originating from the verdant landscape of Alagoas, a northeastern state of Brazil, Queijo de Manteiga, also known as Butter Cheese, […]
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Rennet
Definition and Scope
Rennet is a complex enzyme mixture traditionally sourced from the stomach lining of young ruminants. It contains chymosin and pepsin enzymes that coagulate milk by cleaving casein proteins. This coagulation separates milk into solid curds and liquid whey, forming the foundation for most cheese varieties.
Modern rennet includes microbial alternatives from molds and plant-based coagulants from thistle or nettle. These substitutes allow for vegetarian cheese production while maintaining similar enzymatic functions. The choice of rennet type significantly influences cheese texture, aging potential, and final flavor development.
Production Process
Rennet production begins with extracting the fourth stomach of unweaned calves, lambs, or kids. The stomachs are cleaned, dried, and sliced before being brined to activate the enzymes. This traditional method yields liquid rennet that can be standardized for consistent coagulation strength.
Modern fermentation methods produce microbial rennet through controlled growth of specific mold strains. These microbial enzymes are purified and concentrated to match animal rennet’s clotting properties. Both production methods require precise temperature control and quality testing to ensure reliable milk coagulation performance.
Sensory Profile
Rennet itself contributes minimal direct flavor to finished cheeses but enables flavor development through proper curd formation. The quality of rennet affects cheese texture by determining curd firmness and moisture retention. Poor quality rennet can cause bitterness in aged cheeses due to improper protein breakdown.
Animal rennet typically produces cleaner flavors in long-aged cheeses compared to some vegetable alternatives. Microbial rennets may create slightly different texture profiles in fresh cheeses. The rennet type influences proteolysis rates during aging, affecting both flavor complexity and mouthfeel characteristics.
Practical Applications
Cheesemakers add rennet to warmed milk after starter cultures have acidified it slightly. The standard dosage ranges from 1-5 milliliters per 100 liters of milk, depending on coagulation requirements. Temperature control during renneting is critical, with optimal activity between 30-40°C.
Rennet sets cheese production timelines by determining coagulation speed and curd strength. It enables whey expulsion through syneresis and influences final moisture content. Different cheese styles require specific rennet concentrations and setting times to achieve characteristic textures.
Regional Examples
Traditional European PDO cheeses like Parmigiano-Reggiano and Grana Padano legally require animal rennet. French Roquefort and Spanish Manchego also mandate specific rennet types in their protected designations. These regulations preserve historical production methods and ensure authentic product characteristics.
Many American artisanal cheesemakers offer both animal and microbial rennet versions of classic styles. British territorial cheeses often specify rennet sources on labels for consumer transparency. Regional preferences influence rennet selection, with Mediterranean areas favoring animal rennet and some northern European producers adopting microbial alternatives.