Basically, these are small tablets which are made from the powdering and packing of rennet. These are considerably easier to handle than the more traditional forms of rennet as they were developed for more convenient usage and are used in a wide array of cooking endeavors. One of the most popular brands on the market today is Junket rennet which was named after a pudding made from using rennet. There are numerous recipes which refer to using these particular rennet tablets.
A word about rennet
It usually helps to know a little bit about rennet and how it functions before learning about rennet tablets and using them. Rennet is an enzyme extract which is produced by the linings of mammal stomachs such as cows, goats, and sheep. It aids in the digestion of milk that is produced by the mother and breaks it down so that the nutritional value can be absorbed by the intestinal tract as well as the stomach. Additionally, rennet is used to curdle and/or thicken milk in order to use this in the production of a variety of foods.
The use of rennet dates back centuries and has served as the basic foundation of traditional cheese making. People were oftentimes forced into producing their own rennet in the past but it was quite a messy process that was very unpleasant to perform. The stomachs of certain mammals (see those mentioned above) were removed and then scraped, cleaned, and eventually dried. When rennet is used in this form, a portion of the dried stomach lining must be cut and then soaked in water so it dissolves and can be used in the recipe that is being prepared.
The birth of rennet tablets
As time passed, butchers began offering their customers rennet since it was a beneficial byproduct of their business as well as being an additional source of revenue. Eventually, a number of companies came up with the idea of making the rennet more convenient to use by producing it in either liquid or tablet form. Rennet tablets are about the size of an adult thumbnail, white in color, and scored so that it can be cut into 4 pieces if needed.
Some recipes require using an entire tablet while others only require a portion of the tablet. However, before it is used, it must first be dissolved in water which is critical if rennet is going to function properly. Whenever you are working with rennet tablets, it is important to remember that the enzyme can be deactivated by using high heat, hence the reasoning behind using cool water to dissolve the rennet tablets.
It is also why controlling the temperature of the milk that you are using to make cheese with is so important. Finally, investing in an accurate thermometer is a wise idea if you are making cheese at home along with other equipment such as pans and stirrers. Remember too, that you want to purchase items which can be sterilized after every use.