Wiki: Rennet

USA Old Kirk & Kirk Rennet Storage Bottle - CheeseForum.org

The roots of the term rennet come from rennet derived from animal parts, but in cheesemaking, with modern manufacturing the term is now used broadly to describe a range of chymosin and pepsin based coagulants. This general rennet article discusses formats, storage, amount, and preparation; specific rennet types, their formats and concentrations are in the Rennet Types, A To Z article.

USA Old Kirk & Kirk Rennet Storage Bottle - CheeseForum.org
USA Old Kirk & Kirk Rennet Storage Bottle - CheeseForum.org

Rennet through the ages has been made from the abomasum or fourth stomach, in young un-weaned milk fed calves and contains the rennet enzymes chymosin and pepsin. Due to high cost of manufacture and as calf based rennet does not qualify for some diets and may concern some for animal welfare reasons, starting in the 1990’s other forms of coagulants were manufactured.

Formats

Rennet normally is manufactured and available in a liquid, paste, and powder formats with liquid being the most common by far.

Storage

Most calf based based rennet manufactures recommend:

  1. For liquid calves rennet, store at temperature below 3-7C / 38-45F, i.e. in household fridge, not in normally warmer cheese cave. Store away from direct sunlight to preserve maximum activity (ultra-violet rays in sunlight destroy the rennet activity). Product’s strength will decline at 0.5% per month if ideal storage is followed for all times between manufacture and use.
  2. For powdered calves rennet, store at 38 to 45°F in closed container away from sunlight. This can give high, greater than 1 year shelf life.

Amount

Malaka Brand Vegetarian Liquid Rennet Drop Bottle - CheeseForum.org
Malaka Brand Vegetarian Liquid Rennet Drop Bottle - CheeseForum.org

As rennet can come in different strengths, any specified amount of rennet in a cheese making procedure should be ignored and the amount of rennet used per volume of milk based initially on the manufacturer’s directions. These directions can be found either on the product’s container or from their website (many of these files are posted in CheeseForum.org’s Library in the Forum). This amount should be increased or decreased with the users experience and results with the type of milk they are using.

Note:

  • Rennet degrades based on age and storage best practices, adjust as appropriate.
  • In general, store bought manufactured pasteurized and homogenized milk is requires more rennet than raw milk.

Preparation

  1. For single strength liquid calves rennet, dilute in cool un-chlorinated water at ratio of 15-20 parts water to 1 part rennet by volume.
  2. For powdered calves rennet, dissolve in 400 times it’s weight of non-chlorinated cool water, let sit for 30 minutes with occasional agitation for complete dissolution.
CHR Hansen Brand 75 liter Packages Of Powdered Microbial Fermented Fungus
CHR Hansen Brand 75 liter Packages Of Powdered Microbial Fermented Fungus

Wiki: Rennet Types

CHR Hansen Brand 75 liter Packages Of Powdered Microbial Fermented Fungus

The roots of the term rennet come from rennet derived from animal parts, but in cheesemaking, with modern manufacturing the term is now used broadly to describe a range of chymosin based coagulant. This specific rennet article reviews the different types chymosin based milk coagulants, general information on is in the Wiki: Rennet.

Animal Based

USA Old Kirk & Kirk Rennet Storage Bottle - CheeseForum.org
USA Old Kirk & Kirk Rennet Storage Bottle - CheeseForum.org

Animal based rennet is made from the abomasum of un-weaned milk fed calves. The abomasum is also known as the fourth stomach, and in young animals, the “rennet-bag” or “vell”. The tissue secretes acids and the rennet enzymes chymosin and pepsin. New-born calves have 95% chymosin (sometimes referred to as rennin) and 5% pepsin, as the animal ages and its diet changes from milk to grass, the ratio changes such that at about nine months of age, the ratio has reversed to 10% chymosin and 90% pepsin.

Animal based rennet typically contains 90% chymosin and 10% pepsin in purified form and is considered by many cheese makers to be the preferred rennet. Different ratios are available such as 92-85% chymosin and 8-15% pepsin.

Note, calf based rennet does not qualify for some diets and may concern some for animal welfare reasons.

Formats

Animal derived rennet is normally available in a liquid, paste, or powder formats with liquid easily being the most common.

Liquid format animal rennet contains, in addition to the enzymes chymosin and pepsin, trace proteins, sodium chloride brine, acetate, propylene glycol, caramel color, and flavour preservatives sodium benzoate, and potassium sorbate.

Powdered format animal rennet contains, in addition to the enzymes chymosin and pepsin, sodium benzoate and sodium chloride.

Manufactured liquid calf based rennet is often shipped in large i.e. 5 US gallon containers, and thus hobby Cheese Making Supply Stores often repackage into smaller containers.

Note, rennet paste is normally animal based and made of ground stomachs and brine. As it uses the whole stomach it is also rich in lipase which results in a piquant cheese such as Feta, Provolone, and Romano. Another choice to achieve this effect is to use liquid refined rennet and dried lipase powder.

Concentration

Liquid calf rennet is normally produced in a very concentrated form because when diluted, the enzymes become unstable and lose strength.

Liquid calf based rennet is normally available in single, double strength, and triple strength. To complicate matters, single strength in Europe is different from that in USA.

In the mid 1990’s a new standardization measurement (IDF Standard 157:1992) for rennet was adopted based on IMCU/mL or International Milk Clotting Units per ml of milk.

Fermentation

Malaka Brand Vegetarian Liquid Rennet Retail Box - CheeseForum.org
Malaka Brand Vegetarian Liquid Rennet Retail Box - CheeseForum.org

Until 1990, the only source of chymosin was calves. Around 1990, scientists created a system to make chymosin that doesn’t require calves. Using genetic engineering, the gene for chymosin was cut from a calf cell and inserted into the genomes of bacteria and yeasts such as Kluyveromyces lactis. The microbes replicate and grow rapidly, can be grown continuously, and make an exact copy of calf chymosin.

It can be argued that these rennets are not genetically engineered as nothing was changed in the gene.

This product is often certified Halal or Kosher and suitable for vegetarians.

Approximately 70% of the cheese made in the U.S. are coagulated using fermentation produced chymosin.

Formats

Fermentation produced rennet is normally available in concentrated liquid and powder formats.

Concentration

Fermentation produced rennet is 100% pure chymosin however it can be combined with pepsin to make a more natural animal based type product.

Microbial

Several forms of milk coagulating enzymes are based on microbial fungal sources, the most popular being Rhizomucor miehei, others being Cryphonectria parasitica or Endothea parasitica. Here the mold is grown in large vats and the enzyme extracted and purified and stored with salt.

While microbial rennets are effective at coagulating milk, they are not as good at making aged cheeses as their pathway after coagulation develops poorer flavor and texture than animal based rennet.

In general, microbial based rennets are cheaper than animal based rennets.

Formats

Microbial rennet is normally available in concentrated liquid, powder and tablet formats.

Tablet microbial rennet normally also contains microcristaline cellulose and sodium chloride (table salt).

Concentration

Liquid microbial based rennet is normally available in single or double strength.

Animal Based

CHR Hansen Brand 75 liter Packages Of Powdered Microbial Fermented Fungus
CHR Hansen Brand 75 liter Packages Of Powdered Microbial Fermented Fungus

Examples include thistle or fig leaf.

Formats

Concentrations

Wiki: Calcium Chloride

USA Wisconsin Dairy Connection's Food Grade CaCl2 Aqueous Solution - CheeseForum.org

Calcium Chloride (CaCl2) is frequently added to milk at the start of cheese making as a coagulation aid. This article discusses calcium’s role in mik and coagulation, and properties, availability, and storage of Calcium Chloride.

USA Wisconsin Dairy Connection's Food Grade CaCl2 Aqueous Solution - CheeseForum.org
USA Wisconsin Dairy Connection's Food Grade CaCl2 Aqueous Solution - CheeseForum.org

Calcium & Milk

Milk can have different rennet coagulation abilities and this can be caused mainly by different particle sizes of casein, the main protein in milk. The higher the milk’s content of calcium, the bigger the casein particles will be. The bigger the particles are, the better the coagulation ability of the milk. Secondarily, casein particle size also influences the ease by which cheese curds shrink and releases whey. If the casein particle size is big, the network is open and coarse, and whey drains more readily.

Different factors influence the calcium content of milk:

  • Milk that is stored at low temperatures releases calcium. Thus the pasteurization process of heating and then rapidly cooling milk reduces calcium.
  • Late lactation season milk has low calcium.
  • Milk from diseased animals has low calcium.

To compensate for precipitation of calcium, calcium chloride is frequently added to milk as it is effective, low cost, and has long shelf life.

Calcium Chloride Properties

Calcium Chloride (chemical formula CaCl2) is a salt compound of one calcium and two chloride atoms. It is highly soluble in water and is a deliquescent meaning that in dry form it has a strong affinity for moisture and if left unsealed, will absorb large amounts from the atmosphere and will in time form a liquid solution. CaCl2 is a common additive in the food making industry. Common uses are for salty taste in sports drinks, as a preservative and to maintain firmness in canned vegetables, especially pickles, and in cheese making primarily when using processed – pasteurized milk.

Calcium Chloride Availability

Oil Business Non-Food Grade Calcium Chloride For Making Well Killing Brines - CheeseForum.org
Oil Business Non-Food Grade Calcium Chloride For Making Well Killing Brines - CheeseForum.org

Food grade Calcium Chloride is available from Cheese Making Supply Stores in solution format. It is also available in highly refined form for use in salt water aquariums, but it is not known if those products are human food grade quality.

Note, if the salt (NaCl) content in the milk is too high, ion exchange occurs, so that the calcium is displaced from casein by sodium, which to some extent decreases the milks’ coagulation ability. This is normally not a problem as salt is not normally added to cheese until after rennet coagulation.

Calcium Chloride Storage

In it’s crystaline dry form it should be stored in a dry location where as highly inert it can be kept indefinitely.

In it’s aqueous form it is still enert and requires no special storage.

Wiki: Acids

Table Vinegars For Direct Acidification & Coagulation - CheeseForum.org

In general, three forms of coagulation are popular in making cheese, rennet coagulation, starter culture lactic acid coagulation, and direct acid coagulation. This article discuses different popular food grade acids used in direct acidification of milk, their availability, and the cheese type they are commonly used in making.

Citric Acid

Store Bought Juices For Direct Acidification & Coagulation - CheeseForum.org
Store Bought Juices For Direct Acidification & Coagulation - CheeseForum.org

Citric acid (sometimes called Sour Salt) is a weak organic acid that are in a variety of fruits and vegetables, most notably citrus fruits, with lemons and lime having the highest concentration. Citric acid is commonly used as a natural food preservative, to add an acidic, or sour taste to foods and soft drinks. Most commercially used citric acid come a bacteria and sugar process and is sold as a white crystalline powder or in solution with water.

Availability

  • Canning or ethnic or spice sections sections of large grocery stores.
  • Large bakeries.
  • Wine, beer, and cheese making supply stores.
  • Candy making section of cake supply stores.

Uses

  • Ricotta Cheese
  • Paneer/Panir Cheese

Citrus Fruit Juices

Key Limes For Direct Acidification & Coagulation - CheeseForum.org
Key Limes For Direct Acidification & Coagulation - CheeseForum.org

Citrus fruit juices are used in cheese making due to their high natural citric acid content and as they impart their flavour on the cheese. Commonly used citric fruit juices are from lemons, limes, grapefruit, and oranges.

Availability

  • Made by hand by squeezing fruit.
  • Buying from grocery stores.

Uses

  • Lemon Cheese
  • Paneer/Panir Cheese

Tartaric Acid

Tartaric acid is colorless, odorless, and transparent white crystalline organic acid that occurs naturally in many plants such as grapes, bananas, and tamarinds and is a product of fermentation in wine. It’s primary uses are in the food, pharmaceutical, and chemical industries. In food it is used as an additive to give a sour taste and as an antioxidant. Cream of tartar, often used in cooking, is a derivative of tartaric acid and thus not the same as tartaric acid.

Availability

  • Wine, beer, and cheese making supply stores.

Uses

  • Marscapone Cheese

Acetic Acid (Vinegar)

Table Vinegars For Direct Acidification & Coagulation - CheeseForum.org
Table Vinegars For Direct Acidification & Coagulation - CheeseForum.org

Pure vinegar is a combination of acetic acid and water and is made by the fermentation of ethanol. Common grocery store table vinegar is 5% by volume Acetic Acid, pickling vinegar can be significantly higher. Commercially there are many flavoured vinegar available such as apple cider, balsamic, fruit, malt, rice, white, and wine vinegar. Different cheese making recipes may call for different ones, and normally refer to table type acetic acid concentration vinegars. The word vinegar is derived from French “vin aigre”, or “sour wine”.

Availability

  • Almost every grocery store.

Uses

  • Queso Blanco
  • Ricotta