IMCU stands for International Milk Clotting Units. It measures how strong rennet is and gives you a guideline how much to use. The higher the number, the stronger the rennet and the less you need to use to clot the milk. Strong rennets are hard to measure for small batches of milk. You need about 40 IMCU per litre of milk.
The 65 IMCU Rennet available in 100ml bottles is perfect for the home cheesemaker making batches of cheese with 1-10 litres of milk. It is great for junket, soft cheeses, mozzarella, string cheeses and cream cheeses as well as camembert.
The 250 IMCU Rennet is available in 100ml and 1 litre bottles. The 100ml bottles are for the more serious home cheesemaker with their own dairy animals, making batches of cheese with 10-50 litres of milk, whereas the 1 litre bottles are great for artisan producers. It is excellent to make wheels of cheddar, blues, Raclette, Tomme, Alpine cheeses, camembert and brie. It is also great for soft cheeses, mozzarella, string cheeses and cream cheeses.
The 1370 IMCU powder is highly concentrated and needs dissolving before adding it into milk. One 100g bag coagulates 3400 litres of milk. It is ideal for large producers within NZ and especially overseas (Australia and further) as the shipping is much less than the liquids. If you need larger quantities of 500g or more, please send us an email ([email protected]).
Rennet is exceptionally stable however storage under refrigeration of both the liquid and the powder is recommended.
Dilute rennet (both liquid and powdered) with 15-20 times its own volume of clean, cold water prior to adding it to the milk at 35 C (typically) to get a more even distribution of the enzyme. Dilution water must be free of all residual chlorine.
Store rennet in a cool (3-7 °C) and dark place.
Casein is a very nourishing and complex protein. It is bundled up in micelles, which makes milk free-flowing.
Chymosin enzyme in rennet dissolves envelope (micelle) on the outside of the casein protein, it basically gives it a haircut. It breaks the envelope of curled up casein micelles, so it is no more dissolved in milk. They link up and trap fat in this new network and the milk transforms. Only casein protein turns to curd.
Once the curd is cut, the curd slowly gives off whey due to continued activity of chymosin. The curd is sensitive to heat, agitation and acidity, which changes it, making it more solid and change faster.
We use this rennet for a wide range of cheeses, from soft Mozzarella, Halloumi, cream cheese, Faiselle, Camembert, Valencay to Alpine cheeses, Raclette, Tomme, Cheddar, Stilton and Roquefort.
