MANUFACTURING OF COW’S MILK MOZZARELLA WITH CITRIC ACID

Instructions to make some mozzarella at home in a simple way.

1. Pasteurization of milk for the manufacturing of mozzarella

Pasteurization is a heating treatment to eliminate 100% of pathogen bacteria, and overall approx. 90 % of bacteria in the milk. It is an essential phase that increases and guarantees the healthiness of the product and at the same time it gives a standardization level of the raw material. Pasteurization is obtained by heating the milk up to 72 ° C/15 “(with the pasteurizer) or to 60 ° C for 30 min (slow pasteurization in the boiler).
For the manufacturing of the mozzarella it is convenient a more gentle heating (high temperature can have a negative impact on the stretching characteristics of the curd), without any risk for the safety of the product because the temperatures reached during subsequent stretching phase have a pasteurization effect too.
To manufacture a small quantity of homemade mozzarella, there is no specific contraindications if you use raw milk with the condition that it is a very fresh and good quality milk. On the contrary in case of an industrial production the pasteurization of the milk is mandatory by law, and at the same time it guarantees to the producer a good control of the manufacturing process.
Heating the milk in a pot up to 60 – 65 ° C, with a holding time of 3 – 5 minutes, is already enough for microbial recovery (for cheese manufacture, which does not require the step of stretching, the parameters of pasteurization must be respected).
The following step is the cooling, for example by placing the pot in a bowl of running water (during these operations the milk must be maintained in a constant stirring).
During the cooling phase the milk must quickly reach a temperature below 20° C and then moved to a refrigerator until the cooling is completed at 6 – 12° C within 24 hours. In case of storing for two or three days the milk must be maintained at a lower temperature (4-6° C).

2. The addition of citric acid

The addition of citric acid in the milk is a critical step for the manufacturing of mozzarella, because it is only during this phase that it’s possible to reach the right acidity of the curd, and the consequent optimal characteristics for the stretching. Remember that after the coagulation of the milk you won’t be able anymore to intervene in this regard.
The citric acid is dissolved in some water and added very slowly to cold milk kept in vigorous agitation to disperse quickly the solution in the mass, and avoid the formation of acid lumps that affect negatively the processing. This reaction is much more evident in warm or hot milk, so it is recommended to do this operation with milk below 15° C.
The dose of citric acid varies according to the characteristics of the milk and to the season of the year. It may be around 100 -120 or slightly more per 100 liters of milk, however it must be determined through progressive stretching tests (see paragraph 3) and accurately measured.

INSTRUCTIONS FOR THE PROCESSING OF 50 LT OF MILK (equivalent to approx. 6 kg of mozzarella):
Prepare a solution with 75 g of citric acid dissolved in water for a total volume of 1.5 liters (or a total weight of 1.5 kg). First add 1 liter of this solution to the milk, corresponding to an amount of 50 g of citric acid, theoretically insufficient but an appropriate measure to start to appreciate the stretching characteristics of the curd. Then you proceed with a first stretching test and, in case of need, you can add more solution (for example 50 or 100 ml at a time) and do other stretching tests, until you identify the optimal dose that will be fixed as the processing parameter.

3. Stretching test of the mozzarella
After mixing a portion of citric acid, it is important to perform the stretching test of the mozzarella preparing a small sample of curd from the processing milk to test it with hot water, and make the appropriate corrections before the coagulation phase.
Take a quantity of 250-300 ml of milk mixed with citric acid (milk temperature below 15 ° C) and put it in a pan to heat it around 35 and 40 ° C. Then add approx. 1 ml of liquid rennet, stir it well and stop every inertial movement with the help of a spoon.
The milk coagulates in a very short time (the acidity makes it coagulate much faster than a not acid milk,) and after 2 or 3 minutes the curd is ready to break and you can separate it from the whey.
The addition of very little hot water to warm the mixture gives a better texture to the lumps and facilitates the separation of the curd, with the help of a strainer (better if a plastic one) or a pierced plastic mould.
The sample obtained is squeezed gently with the hands to remove the whey in excess, then smashed into a strainer placed in a bowl with hot water at 80 – 85° C covering the curd for a couple of inches.
With the help of a stick, you handle the curd for a few seconds to heat it well, then you take it and stretch it with the hands to appreciate the stretching characteristics of the mozzarella. The optimal point is reached when it is possible to stretch the curd, spreading the arms without breaking the structure, but a proper evaluation requires some experience acquired with practice.

4. Preparation of the curd

After fixing the right amount of citric acid, heat the milk to 36-37 ° C and add the rennet, preferably diluted in some cold water, then stir it well and stop any inertial movement of the mass. With a rennet of title 1:10.000, it is normally used a dose of 25 – 35 ml/100 lt of milk, but the optimal dose may vary depending on the characteristics of the milk.
The milk begins to coagulate in a few minutes and usually after 15-20 min the curd is sufficiently consistent for cutting. If you don’t have a cutter you can make some cross cuts 2 -3 cm away from one another with a knife, then mix and cut gently the curd with a ladle to get lumps of hazelnut size and keep stirring it for a few minutes.
The curd must rest from twenty to thirty minutes to settle on the bottom of the pot in order to consolidate, then the whey is removed, and finally the curd is placed on a table to drain off the excess whey, ready for the next phase of stretching.

5 – Mozzarella Stretching

Since this is a very critical phase, which should be performed also with a certain speed, it is recommended to divide the curd obtained into two or three parts so you can stretch a couple of pounds at a time, using a basin, even in plastic material, with a diameter of 30 – 35 cm.
The water used must reach a temperature of 82-85 ° C and it can be salted at the rate of 250-350 gr per 10 liters of water (the dose could vary depending on the flavor required), to obtain the salting of the product directly during the stretching phase.
The curd is shredded or cut into thin slices and handled with a stick and with plenty of hot water. At the beginning the volume of the water used should be approx. the double of the volume of the curd, but during the manipulation some extra water may be gradually added to obtain a softer and juicier product. The consistency of the final product depends in large part on the amount of water used during the stretching phase and on the manual skill of the producer to perform the operations.
The excess of water must be removed when the curd is well stretched and homogeneous, to proceed to the molding of the mozzarella in the size required. It is important that the molded mozzarella is immediately placed in fresh water (room temperature) to cool down and stir it frequently until completely consolidated (firming).
The mozzarella obtained is kept immersed in normal water until consumption.