34% moisture, 25% fat (see, Table 6.1).
Romano, along with its many hard Italian cousins, is made from low fat milk. A PF ratio of 1.50 will ensure compliance with Canadian composition standards (see, Table 6.1). Most hard Italian cheeses must be made from raw milk to comply with Italian PDO (Protected Designation of Origin) standards. Most Canadians don’t realize that they routinely consume raw milk cheese.
- Pasteurize (72°C, 16 s or 62°C, 30 min).
- Add sufficient DVS thermophilic cultures to produce pH of 6.1 – 6.2 ready for draining after about 3 h. Normally Streptococcus thermophiles and Lactobacillus bulgaricus cultures are used in equal proportions. Alternatively, Lactobacillus helveticus can be used instead of bulgaricus.
- Ripen at 30 – 31°C for about 15 min.
- While the milk is ripening: (1) add 20 mL of a solution of 30% CaCl2 per 100 Kg of milk; and (2) if desired, add 0.1 – 0.5 g of lipase per 100 Kg milk.
- Measure 5,000 IMCU of coagulant per 100 Kg milk. Dilute the coagulant in at least 200 mL of water per 100 L of milk. Ensure the milk temperature in the vat is stabilized at 30 – 31°C; then add the diluted rennet into the vat with the agitators running. Agitate for about two minutes and then remove the agitators. Setting should occur in 30 – 40 min.
- Cut when the curd breaks cleanly; cut quite vigorously until the curd is the size of rice grains.
- Slowly increase the temperature to 46°C during 50 min and hold at 46°C until the pH is 6.1 – 6.2.
- When the pH is 6.1 – 6.2, allow the curd to settle. Then push the curd away from the gate and level it beneath the surface of the whey. Drain the whey. Cut portions of the curd to fit dressed hoops. In the Guelph lab, use a 25 Kg cylindrical hoop.
- Allow 20 min without pressing; then stack the hoops double for 20 min. Reverse the hoops and hold for another 20 min. Then, press for 60 min at 100 kP (14 psi); then, hold overnight at room temperature (20°C) without pressure.
- Place cheese in 20 – 23% salt brine for periods estimated from the cheese weight and thickness as 1 h per 0.9 Kg per cm OR 1 h per pound per inch. The larger blocks will require up to 96 h.
- Dry cheese for 48 h at 10°C and 85% RH.
- Cure at 10 – 15°C for at least 5 months and regularly rub the surface with mineral oil. Alternatively, the cheese may be sealed and ripened in plastic film..
2. Swiss type
Swiss (Emmentaler) cheese was first made in the fifteenth century in the Emmental Valley. Swiss varieties made in other areas are known by local names: Gruyere (Switzerland), Allfauer Rundkase (Bavaria), Battlematt (Switzerland), Fontina (Italy), Traanon (Switzerland), and Samso (Denmark). Swiss is traditionally made in copper kettles, drained using a cloth and formed into large wheels of up to 130 Kg. The procedure described here is for a rindless Swiss type that is formed in a press table in approximately 20 Kg blocks, brine salted, and then film wrapped for curing.
The distinctive feature of Swiss cheese is the formation of eyes by the gas forming bacteria Propioni bacterium shermanii. The manufacturing procedure is designed to provide the right chemical composition for the growth of shermanii and the right texture (sufficient elasticity) for eye formation. Important manufacturing parameters are: (1) high draining pH (about 6.3), which promotes retention of minerals; (2) high cooking temperature (52°C) which promotes mineral retention and the loss of both moisture and lactose by syneresis; (3) high final pH (5.3 – 5.4) and mineral content which promote elasticity.
40% moisture, 27% fat (see, Table 6.1).
A PF ratio of 1.1 will ensure compliance with Canadian composition standards for Emmentaler (see, Table 6.1). Most European Swiss type varieties (Emmentaler, Gruyere, Comté) must be made from raw milk to comply with local or international standards such as the AOC and DPO standards.
- Pasteurize (72°C, 16 s or 62°C, 30 min).
- Add sufficient DVS Thermophilic cultures to produce pH of 6.3 – 6.4, ready for draining, after about 2 h, and pH 5.1 in the cheese 15 – 18 h after inoculation. Normally, Streptococcus thermophilus and Lactobacillus bulgaricus cultures are used in equal proportions. Alternatively, lactobacillus helveticus can be used instead of bulgaricus. For eye formation, cultures containing Propionibacterium freudenreichii subsp freudenreichii or subsp shermanii are used.
- Ripen at 37°C for about 15 min.
- While the milk is ripening add 20 mL of a solution of 30% CaCl2 per 100 Kg of milk.
- Measure 5,000 IMCU of coagulant per 100 Kg milk. Dilute the coagulant in at least 200 mL of water per 100 L of milk. Ensure the milk temperature in the vat is stabilized at 37°C; then add the diluted rennet into the vat with the agitators running. Agitate for about two minutes and then remove the agitators. Setting should occur in 20 – 25 min.
- Cut when the curd breaks cleanly but is still a little soft. The curd firms quickly due to the relatively high setting temperature, so it is important not to start cutting too late. Cut quite vigorously until the curd is the size of rice grains.
- Stir out the curd with vigorous agitation until the curd is firm and resilient when gently pressed (30 – 60 min) in the hand. There should be little acid development at this point (pH 6.55 – 6.50).
- Cook the curd from 37°C to 52°C in 30 min. Heat slowly at first (1 – 1.5°C in 5 min). Rapid heating causes “case hardening” which traps moisture and acid inside the curd particles. Curd cooked too slowly may also be too acid. Continue vigorous agitation to prevent matting until the pH is 6.3 – 6.4. Experienced cheese makers look for the proper “grip” before removing the whey. Curd pH should not be less than 6.3 at whey separation.
- Draining can be accomplished by pumping or dipping curd and whey into a curd table. The curd may then be transferred to rectangular or round forms. In the Guelph pilot plant, place one large round hoop (20 Kg capacity) in the curd table and transfer sufficient whey to cover it. Then dip curd and whey into the hoop, gradually displacing the whey until all the all the curd is in the hoop. Lower the level of whey as required and save some warm whey to help dress the cheese later. When the cheese in the hoop is sufficiently consolidated, remove the hoop, dress the cheese with cheese cloth, and put the wheel back in the form. Cover the hoop with cloth lined cover, add weights and let stand for one hour. Then open the hoop, redress the cheese, put it back in the hoop, and then put the hoop back in the warm whey. Put the weights back in place and press under the whey for another hour. Then drain the whey and press overnight (12 – 18 h).
- Remove the press plates and cloths. Cheese pH at this time should be 5.2 – 5.4.
- Place cheese in 20 – 23% salt brine for periods estimated from the cheese weight and thickness as 1 h per 0.9 Kg per cm OR 1 h per pound per inch. After brining, immerse the cheese in the brine to remove salt particles from the surface and then store at 10°C to dry the surface.
- Gas flush the blocks in pouches sufficiently large to permit expansion (15 – 20%) during eye formation.
- Store at 10°C for 8 – 10 days for cooling and pre-ripening. Then, transfer to the warm room (23°C) for curing and eye formation.
- When eye development is complete (2 – 3 weeks), place the cheese in the finishing cooler (2 – 5°C) to stop eye development and to firm the cheese in preparation for cutting. Flavor development continues in the finishing cooler.
Acid Development and Ripening
Drainage in the press is affected by the rate of acid development which in turn is affected by the curd temperature and the activity of the organisms. At draining, the temperature is too high for any of the organisms to grow but as soon as the curd cools to about 49°C, S. thermophilus (cocci) begins to grow. The rods (L. helveticus) begin to grow about 5 h after draining when the temperature in the cheese is about 45°C and growth factors have been provided by the metabolism of the cocci. The following morning the temperature of the curd should be about 36°C. Too rapid cooling does not allow enough acid development. The pH changes during curing are:
|21 hr||5.00 – 5.15|
|15 days||5.20 – 5.25|
|30 days (eye formation)||5.30 – 5.35|
|75 days||5.45 – 5.55|
|6 months||5.50 – 5.60|
|9 months||5.60 – 5.90|
The numbers of both rods and cocci decrease rapidly during the first 15 – 30 days of curing. Propioni bacteria multiply rapidly to about 100 million/g during 6 – 8 weeks. Propioni bacteria ferment lactic acid and produce propionic acid, acetic acid, water, and carbon dioxide. Eyes formed by carbon dioxide production should be 1.9 – 2.5 cm in diameter and should be spaced 2.5 – 7.6 cm apart. The number of eyes depends on the rate of gas production. If gas is produced too rapidly, the cheese will be overset with many small eyes. Little or no gas production causes a “blind” cheese. Any factor causing weakness or brittleness of the curd will result in defective eyes.
Glasler: brittle curd resulting in defective or too few eyes.
Pressler: pin holes due to contamination with Aerobacter aerogenes or Bacillus polymyxa.
Nissler: clusters or nests of holes possible due to lactose fermenting Clostridia sp. or an accumulation of fat in the area.
Late gas formation: due to Clostridium butyricum or Clostridium lentoputrescens, which produce stinker cheese with excessive gas, are inhibited at pH < 5.3.