rennet

noun

ren·​net ˈre-nət 

1

a

: the contents of the stomach of an unweaned animal and especially a calf

b

: the lining membrane of a stomach or one of its compartments (such as the fourth of a ruminant) used for curdling milk

also : a preparation of the stomach of animals used for this purpose

2

a

: rennin

b

: a substitute for rennin

Examples of rennet in a Sentence

Recent Examples on the Web

Traditional Parmigiano-Reggiano hinges on animal rennet. —Ali Francis, Bon Appétit, 8 Oct. 2023

Vegetable rennet or plant rennet: Typically, this will be referring to the variety that’s derived from plants like thistle and nettle. —Ali Francis, Bon Appétit, 8 Oct. 2023

Parmesan makers also use rennet, however unlike Parmigiano Reggiano, the rennet used can be vegetarian. —Michelle Manetti, Good Housekeeping, 14 Nov. 2022

Do vegetarian enzymes taste different from animal rennet? —Ali Francis, Bon Appétit, 8 Oct. 2023

Videos posted on TikTok and posts on Twitter this year kicked off waves of people surprised to learn that parmesan cheese is usually not vegetarian — because it is made using calf rennet, an enzyme derived from the stomach lining of animals. —Emily Heil, Washington Post, 3 Aug. 2023

Animal rennet is an enzyme that’s extracted from the stomach lining of cows.1 The reason it’s added to parmesan cheese (and many other cheese products like gorgonzola, pecorino romano, gruyere, and manchego) is because the enzyme helps separate milk into curds, which creates the actual product. —Brittany Leitner, Better Homes & Gardens, 9 May 2023

To solidify milk into cheese, rennet is commonly added to curdle the protein in milk: this complex of enzymes is produced in the stomachs of ruminant mammals. —Ashton Yoon, Discover Magazine, 26 Sep. 2017

In the 1980s, cheesemakers recreated rennet, an enzyme found in the lining of calves’ stomachs, through fermentation and stopped harvesting it from cows. —Claire Bugos, Verywell Health, 4 Apr. 2023

Word History

Etymology

Middle English, from Middle English *rennen to cause to coagulate, from Old English gerennan, from ge- together + *rennan to cause to run; akin to Old High German rennen to cause to run, Old English rinnan to run — more at co-, run

First Known Use

15th century, in the meaning defined at sense 1a

Kids Definition

rennet

noun

ren·​net ˈren-ət 

1

a

: the contents of the stomach of a young animal and especially a calf

b

: a part of the lining of the stomach that is used to curdle milk

2

: something used to curdle milk

especially : rennin

Medical Definition

rennet

noun

ren·​net ˈren-ət 

1

a

: the contents of the stomach of an unweaned animal and especially a calf

b

: the lining membrane of a stomach or one of its compartments (as the fourth of a ruminant) used for curdling milk

also : a preparation of the stomach of animals used for this purpose

2

a

: rennin

b

: a substitute for rennin