10 Mistakes Beginners Make
in Cheesemaking —
and why they're completely normal

Pasteurisation is an essential step — it makes milk safe and stabilises its microflora. But overheating is one of the most fundamental mistakes a beginner can make. It affects every stage that follows: coagulation, cutting, curd grain formation, whey separation, and ageing.

What happens to milk proteins when overheated?

Above 65°C, whey proteins begin to unfold and clump together. Above 75°C, denaturation is complete — they form a "cooked" mass that can no longer participate in coagulation. They coat the casein micelles, block the enzyme, and produce a weak, watery, unstable curd.

What happens to calcium?

In normal milk, calcium is balanced between colloidal and dissolved forms. Overheating shifts this balance — some calcium becomes unavailable. The enzyme can no longer bind the casein micelles. The curd forms slowly, or not at all. The grain won't hold its shape, and whey separation becomes erratic.

In cheesemaking, there are no insignificant details. The quality of the water you use to dissolve your rennet or calcium chloride directly affects coagulation stability and enzyme activity. In professional dairies, this is strictly regulated. At home, it's often ignored.

• Chlorine is a powerful oxidiser — it can partially or fully deactivate the coagulating enzyme. The result: a weak, watery, fragile curd.
• Chlorine + CaCl₂ — calcium ions enter side reactions and become unavailable to casein micelles. The curd can't set properly.
• Hard water alters pH and disrupts the mineral balance that coagulation depends on.
• Untreated water may carry E. coli, pseudomonads, yeasts, or moulds that colonise the cheese at the earliest stages.

How you add rennet to milk determines not just the speed of coagulation, but the firmness of the grain, the cleanness of the cut, whey separation, and the final result. The rennet must contact casein micelles evenly and simultaneously — so coagulation begins uniformly throughout the entire volume.

If you pour rennet quickly or in a single spot without mixing, it concentrates locally and begins working in patches. Local clumping forms while the rest of the milk is still unready.

The moment the knife first touches the set curd is the moment that shapes the cheese's entire character. Too early, and the curd is weak — the grain doesn't form, protein leaks into the whey, yield drops, and the final cheese is dry or crumbly. Too late, and the curd is overdense — the grain is too large, retains too much moisture, and the cheese ends up wet and unstable.

• Cut too early: small, unstable grain → rapid moisture loss → dry, brittle cheese
• Cut too late: oversized grain → moisture trapped inside → wet, sour, structurally flawed cheese

Temperature is the greatest conductor in cheesemaking. It controls how quickly cultures work, how acidity develops, how the grain structure forms, and how properly whey drains. A single degree in the wrong direction changes everything.

• Too cold: bacteria work slowly → pH drops slowly or not at all → weak, watery curd → slimy, unstable cheese
• Too warm: bacteria overproduce acid → brittle curd → dry grain → sour, crumbly cheese

During whey drainage, temperature determines how quickly the grain "closes" and how evenly moisture leaves. Too cold — moisture is trapped inside. Too warm — the structure becomes coarse and rigid, with internal cracking during ageing.

Stirring is how you keep the grain from clumping and help it release whey evenly. But when it's done too forcefully, the grain breaks into dust — and protein leaves with the whey instead of staying in the cheese.

• Broken grain → excessive and uneven moisture loss → dry, lifeless cheese
• Fat leaves with the whey → lower yield, poorer flavour
• Rough grain surface → uneven whey drainage → dry and wet spots inside the cheese

Heating the grain too quickly causes thermal shock — the outside sets before the inside has drained. Moisture becomes trapped, uneven density forms, and the interior develops "wet pockets" — ideal conditions for unwanted bacteria.

Salt is not just flavour. In cheesemaking, it is a regulator, a stabiliser, and a protector — affecting moisture, texture, microbial balance, acidity, and shelf life.

• Insufficient salt → proteins retain excess moisture → the cheese stays wet, soft, and unstable
• Salt imbalance → lactic bacteria overwork → cheese becomes too sour; unwanted bacteria thrive
• Without salt, uncontrolled proteolysis → soapy texture, runny surface, sharp or empty flavour

Under-salted cheeses most vulnerable: Camembert, Brie → surface slime, bitterness. Dutch-style → bloating, acid defects. Aged hard cheeses → unstable breakdown, crumbling.

The desire to make the cheese "firm" often leads to excess weight during pressing — and that breaks the internal grain structure. The result is a cheese that's hard, dry, acidic, or cracked. Pressing is not about force. It's about gradually forming a firm, breathable structure.

• Grain compresses too fast → protein-fat bonds don't form evenly → rigid body with closed "pockets"
• Grains are forced together instead of flowing → cracks and delamination during ageing
• Structure becomes too dense → the cheese can't breathe → uneven maturation, flat flavour

Drying is the transitional stage between making and ageing. This is where the surface prepares to welcome the right microflora, salt distributes evenly, and the rind forms without defects.

Too fast (low humidity, draft, cold air):

• Rind forms too quickly → moisture can't escape from the centre → internal wet zones
• Unwanted microflora develops where moisture is trapped
• Surface cracks as it can't keep up with internal changes

Too slow (high humidity, poor ventilation):

• Surface stays wet too long → ideal for slime microflora
• Mould growth goes out of control before the rind even forms
• Uneven maturation, spongy or doughy texture

Mould is the word that frightens most beginners. Any fuzzy patch or coloured spot is seen as a sign of spoilage or danger. But mould is a natural part of the cheesemaking world — and in many traditions, it is not a problem. It is a technology.

Fear of mould causes a chain of errors: excessive washing, over-drying, under-salting, and panicked interventions in the ageing process.

Moulds that are often normal:

• Mucor ("cat fur") — early surface flora, common in the first weeks of ageing
• Light grey or blue — early Penicillium from the environment
• Pale green — also typically Penicillium, usually harmless

What mould tells you:

• Appears very early → too much moisture, weak drying
• Grows in a ring → cheeses placed too close together
• Only on top → poor ventilation
• Aggressive colony → too little salt or too much humidity
• Spots in different places → inconsistent hygiene