Cheese Making Process

The Cheesemaking Process — Overview

All cheese, from Cheddar to Parmesan to mozzarella, follows the same fundamental seven-step process:

Cheesemaking Equipment

A commercial cheesemaking line requires the following equipment, sized to the planned cheese type and output:

• Milk reception silos and whey tanks — for raw milk holding and whey storage prior to drying or further processing
• Cheese milk pasteuriser — a plate heat exchanger designed to bring milk to cheesemaking temperature (typically 30–34°C for most cheeses) after pasteurisation
• Centrifugal separator — to remove cream and standardise fat content
• Standardisation system — to blend cream and skim to the target fat:casein ratio (see our Pearson's Square calculator or milk standardisation by cream removal)
• Cheese vat — an enclosed jacketed vessel for inoculation, coagulation and curd cutting. Capacities range from 1,000 L to 20,000+ L
• Continuous coagulator — an alternative to batch vats for very high-volume operations (Cheddar, mozzarella)
• Curd draining belt or matting/cheddaring table — to separate curds from whey, allow further drainage and (for Cheddar) matting
• Cheese moulds or moulding system — either traditional fixed moulds or continuous block formers for industrial Cheddar
• Brine tank or dry salting system — for surface or whole-curd salting
• Ripening rooms — temperature and humidity controlled; for some cheeses, separate maturation rooms at different temperatures
• Packing line — vacuum bagging, waxing or paper wrapping depending on cheese type

Step 1: Treatment of Milk for Cheesemaking

Standardisation

The first step is to bring the milk's fat-to-casein ratio to the target value for the cheese being made. Cheddar typically targets a fat:casein ratio of around 0.7–0.75 for half-fat varieties and 0.96 for full-fat. Mozzarella runs lower (around 0.8–0.9). Feta and other Mediterranean cheeses are different again.

Standardisation is normally done with a centrifugal separator (removes cream) plus blend-back of cream to hit the target. See the milk separator page for separator operation details and the Pearson's Square calculator for the standardisation math.

Heat treatment — thermisation, pasteurisation and beyond

The milk may first be thermised (64.5°C for 16 seconds) on receipt to reduce bacterial count before storage. Thermisation is not a substitute for pasteurisation but extends the safe holding window.

For final processing, HTST pasteurisation at 72°C for 15 seconds is the standard. Some specialty cheeses (e.g. traditional raw-milk cheeses in EU PDO categories) skip pasteurisation, relying on long ripening to control pathogens. See our pasteurisation F-value calculator for time-temperature equivalence.

Higher temperatures (e.g. 85–90°C for soft cheeses) may be used to denature whey proteins and increase cheese yield via inclusion in the curd. The trade-off is potentially weaker curd structure.

Homogenisation

Homogenisation breaks up fat globules and increases the surface area where casein particles attach. This may give a weaker / softer curd, so is normally not used for hard cheeses but is common for cream cheese and some soft cheese types.

Additives

The following may be added to cheese milk (check your country regulations):

Step 2: Inoculation and Milk Ripening

The milk is inoculated with starter culture — usually a defined-strain mesophilic or thermophilic culture from a commercial supplier (Chr Hansen, DSM-Firmenich, etc.). The culture's job is to convert lactose to lactic acid, lowering pH and creating the conditions for coagulation and flavour development.

The milk is then held at the cheesemaking temperature (typically 30–32°C for mesophilic cheese, 38–42°C for thermophilic Italian cheeses) for a ripening period of typically 30–60 minutes until the titratable acidity reaches the target rise.

Step 3: Coagulation

Coagulation is the conversion of liquid milk into a gel. There are two main mechanisms:

Rennet coagulation (most cheeses)

Rennet contains the enzyme chymosin, which specifically cleaves k-casein on the casein micelle surface. This destabilises the casein structure and allows the micelles to aggregate, trapping fat globules and water in a gel network. Rennet is dosed at typically 20–40 mL per 100 L of milk; coagulation takes 30–45 minutes.

Acid coagulation

Lactic acid produced by the starter culture (or direct acidification) lowers the pH to around 4.6 (casein isoelectric point) and causes the casein to precipitate directly. This is used for cottage cheese, cream cheese and quark.

The "cut" — cutting the coagulum

Once the gel has reached the right firmness, the cheesemaker uses cheese knives or wire cutters to cut the gel into curd pieces. Cut size determines moisture content: small cuts (pea-sized for Cheddar) give drier, harder cheeses; large cuts give moister, softer cheeses. Cut timing is judged by feel, modern in-line measurement (e.g. CoaguLite optical sensors) or experience.

Step 4: Whey Removal (Syneresis)

After cutting, the curd is stirred and gradually heated. This drives whey out of the curd pieces (syneresis). The process is controlled by:

• Cut size — smaller cuts release more whey faster
• Stirring intensity — more stirring increases whey release
• Cooking temperature — higher temperature releases more whey but firms the curd more
• Cooking time — longer time releases more whey
• pH — lower pH increases syneresis rate

Whey is drained off when the curd has reached the target moisture. For Cheddar this happens at around pH 6.1; for Parmesan, much lower.

Step 5: Curd Handling & Salting

Pressing and forming

The curd is transferred to moulds (or a continuous block former for Cheddar) and pressed to remove additional whey, knit the curd grains together, and form the final shape. Pressure ranges from light (a few kg for soft cheeses) to heavy (100+ kg/cm² for hard cheeses).

Salting

Salt is added by one of three methods, depending on cheese type:

• Dry salting of curd — salt is mixed with the cut curd before pressing (Cheddar, Cheshire, some Italian cheeses). Typical addition: 1.5–2.5% by weight of curd.
• Surface dry salting — salt rubbed on the cheese surface daily for several days (some farmhouse cheeses)
• Brine immersion — cheese immersed in 18–22% brine for hours to days (Edam, Gouda, Mozzarella, Feta, Parmesan). Brine concentration, temperature and time control salt uptake.

Salt does several jobs: controls microbial growth, accelerates whey expulsion, contributes to flavour and texture, and acts as a preservative.

Step 6: Cheese Ripening (Maturation)

Cheese ripening is the slow biochemical transformation that develops flavour, aroma and texture. It takes minutes (fresh cheese) to years (extra-mature Parmesan, vintage Cheddar). Three sets of reactions drive it:

• Glycolysis — residual lactose converted to lactic acid
• Lipolysis — fats broken down by lipases into free fatty acids (significant in blue cheeses, Italian cheeses, Roquefort)
• Proteolysis — proteins broken down by residual rennet and microbial enzymes into peptides and amino acids (most important for flavour development in aged cheeses)

Temperature and humidity in the ripening room are tightly controlled. Cheddar typically ripens at 8–12°C, 85% relative humidity. Italian hard cheeses run warmer (15°C). Blue cheeses need specific Penicillium roqueforti or P. glaucum environments. See our cheese racking guide for ripening room design considerations.

Cheese Yield — The Commercial Reality

Cheese yield is normally expressed as kg of cheese per 100 kg of milk. Typical yields:

The classic Van Slyke formula predicts cheese yield from milk fat, protein and target moisture:

Frequently Asked Questions

What is the basic cheesemaking process?

The seven steps are: milk standardisation and heat treatment, addition of cultures and additives, ripening, coagulation by rennet or acid, whey removal, curd handling and salting, and ripening/maturation. Every cheese type follows this framework with variations in time, temperature, pH and cut size that produce the final character.

How is cheese yield calculated?

The standard formula is Van Slyke: Y = ((F × RF) + (C × RC)) × 1.09 / (1 - M), where F is milk fat %, C is casein %, RF and RC are retention factors, M is moisture %. See our Van Slyke calculator for worked examples.

What temperature is milk heated to for cheese making?

The milk is pasteurised at HTST 72°C/15s for safety, then cooled to the cheesemaking temperature: 30–32°C for mesophilic cheeses like Cheddar, 38–42°C for thermophilic cheeses like mozzarella and Parmesan. Higher pasteurisation temperatures (85–90°C) are sometimes used for soft cheeses to denature whey proteins and improve yield.

How long does it take to make cheese?

The make process (from milk to formed cheese) takes 4–8 hours for most cheeses. Ripening then takes anywhere from days (fresh cheese, cream cheese) to years (extra-mature Cheddar, Parmesan, vintage Gouda). Soft cheeses are typically ready in 4–6 weeks; semi-hard like Edam in 2–3 months; hard cheeses like Cheddar in 6 months to 3+ years.

Why is calcium chloride added to cheese milk?

Pasteurisation precipitates some of the calcium phosphate naturally present in milk. Adding CaCl₂ back at 10–30 g per 100 L restores the calcium balance, improves coagulation speed and firmness, reduces rennet requirement and improves cheese yield. It is permitted in most jurisdictions including the UK and EU.

What's the difference between rennet and acid coagulation?

Rennet (chymosin enzyme) specifically cleaves the k-casein surface protein, allowing casein micelles to aggregate while still trapping fat and water — producing the firm gel needed for most hard, semi-hard and soft rind cheeses. Acid coagulation precipitates casein directly at its isoelectric point (pH 4.6) and produces a softer, more granular curd suited to cottage cheese, cream cheese and quark.

Can you make cheese from UHT milk?

Not satisfactorily. UHT treatment denatures the whey proteins and damages the casein micelles to the point that rennet cannot coagulate the milk properly. The resulting curd is weak and the yield very poor. Cheese making requires raw or HTST-pasteurised milk.

Further reading: John Watson publishes articles on cheese making and dairy industry topics on LinkedIn. Browse all articles by John Watson on LinkedIn →

See related cheese pages: Cheese Yield (Van Slyke) calculator, Mozzarella cheese, Blue cheese, Feta cheese, Cheese racking & ripening, Soft cheese & EMC, Pearson's Square (milk standardisation), Pasteurisation F-value calculator, all dairy science information, or browse all consultancy services.