Cheese Making and Kashrut

For those of use who have a love of cheese making and a concern for Kashrut (keeping kosher), cheese making presents some unique challenges.  Rennet which is used to separate milk solids, lipase which adds flavoring to (mostly) Italian hard cheeses, and basic cultures which gives cheese its unique flavor all have a variety of Kashrut issues.


The first issue is rennet; rennet is the key ingredient which allows milk to separate into solid and whey.  Rennet as a chemical is harvested from the stomachs of animals and is therefore not kosher.  Three forms of rennet that are not produced from animal sources have been created over time, they are:

  1. Vegetarian Rennet – or vegetable rennet, sources include nettles, thistles, mallow, ground ivy, and unfermented soybeans.  Vegetable rennet has a poor reputation as having a ‘off’ taste as the cheese matures or ages.  Gianaclis Caldwell (Pholia Farm) who taught us that vegetarian rennet is great if used in MODERATION and that most new cheese makers    over rennet their cheese.
  2. Microbial Rennet – Produced from some molds such as Rhizomucor miehei are able to produce proteolytic enzymes (the active ingredient in animal rennet), these are both vegetarian and kosher.  These rennets also have a reputation for adding bitterness to the cheese after long periods of maturation (the worst kind of rennet behavior :-))
  3. Genetically Engineered Rennet – Starting in the early 1990’s, engineers created a genetically engineered form of rennet.  These have become so popular that by 2008 over 80% of all cheese made in the US used this type of rennet.  These are often a combination of genetically engineered chymosin and natural pepsin to create this rennet.  Until recently, this rennet was unavailable in small quantities, now it’s both available and has an OU heksher.  The Cheesemaker has hobby quantities available for purchase.


Lipase powder is generally used in the production of all (or most) of the italian cheese (Feta, Romano, Parmesan, Mozzarella etc.)  Lipase is also an animal byproduct and therefore is not kosher.  A recent Genetically engineered version has become available including one that is kosher.  When I inquired last year, the minimum shipment size was a container truck. 🙂  What I’ve concluded is the quality of milk is more important than the addition of Lipase; I’ve made lots of successful feta, mozzarella and even a parmesan without lipase.  Maybe in a few years we can get kosher hobby sizes.


Cheese cultures are bacteria specimens that are needed along with time to ripen which produce a cheese’s taste and texture.  Cheese cultures are not from animal sources and you can get hekshered cultures from the cheesemaker.

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