Discard the batch. Likely causes: Culture inactive or too little of it; Room too cold or too hot for a mesophilic culture, which works at 20–30 °C. What to do: Discard the batch, as you would a yogurt that failed to set; Check the room temperature and use the culture dose on the pack.

Likely causes: Left to sour long past the set; industrial quark is taken at about 16 hours; A warm room speeds souring. What to do: Start draining as soon as the curd has set; Use the cooler end of the range next time.

Likely causes: Drained too briefly; Curd cut or ladled before it set. What to do: Drain longer, covered in the fridge; A trace of rennet gives a firmer curd.

Likely causes: Drained too long or pressed; Skim milk gives a leaner, drier curd. What to do: Drain for less time, or stir a little cream or whey back in; Try part whole milk in the next batch.

Discard the batch. Likely causes: Contamination; fresh cheese is moist and spoils easily. What to do: Discard the whole cheese; Eat fresh cheese within 5–7 days.

Troubleshooting · New on 9 October 2026

Tvorog and fresh cheese problems and fixes

Milk that will not set, a curd too sour, too wet or too dry: likely causes and fixes for home tvorog and quark, and when to discard.

The method Record the batch

Fresh cheese depends on a mesophilic culture working at room temperature and on how long you drain. Primary sources give the industrial parameters, not a home troubleshooting table, so the advice below reasons from those parameters and stays conservative. ⁵⁴

The milk did not set

Discard the batch. Do not try to rescue it.

Likely causes

Culture inactive or too little of it ³
Room too cold or too hot for a mesophilic culture, which works at 20–30 °C ⁴

What to do

Discard the batch, as you would a yogurt that failed to set ²
Check the room temperature and use the culture dose on the pack ⁴³

Too sour

Likely causes

Left to sour long past the set; industrial quark is taken at about 16 hours ⁵
A warm room speeds souring ⁴

What to do

Start draining as soon as the curd has set
Use the cooler end of the range next time ⁴

Too wet or runny

Likely causes

Drained too briefly ⁶
Curd cut or ladled before it set

What to do

Drain longer, covered in the fridge ⁶
A trace of rennet gives a firmer curd ⁵

Too dry or crumbly

Likely causes

Drained too long or pressed
Skim milk gives a leaner, drier curd ⁵

What to do

Drain for less time, or stir a little cream or whey back in
Try part whole milk in the next batch

Mould on the curd

Discard the batch. Do not try to rescue it.

Likely causes

Contamination; fresh cheese is moist and spoils easily ⁷

What to do

Discard the whole cheese ¹
Eat fresh cheese within 5–7 days ⁷

Change one thing at a time

When a batch disappoints, compare it with the method, change one variable, and note the result in a Batch Card. Two changes at once hide which one helped.

Sources

UConn Extension: Handling food with mould (citing USDA FSIS)Yogurt, sour cream and soft cheeses such as cottage and cream cheese are discarded entirely if any part is mouldy. Accessed 2026-10-09.
University of Alaska Fairbanks Cooperative Extension: Making yogurt at home (FNH-00062)Heat to 85–93 °C (185–200 °F) for 10–20 minutes, do not boil; culture is killed above 54 °C (130 °F) and grows poorly below 37 °C (98 °F); adding culture to milk over 46 °C (115 °F) can kill it; incubate 4–7 hours at 43 °C (110 °F); sets at pH 4.6; one 5 g freeze-dried packet or ¼ cup yogurt per quart; discard batches that fail to set or show microbial growth or odd odours; keeps about 10–21 days at 4 °C. Accessed 2026-10-09.
Danisco CHOOZIT MA 4001 product descriptionA mesophilic culture maker gives 2.5–5 DCU per 100 litres of milk for quark: culture doses are set by the maker per volume of milk. Accessed 2026-10-09.
Tetra Pak Dairy Processing Handbook: Cultures and starter manufactureMesophilic cultures grow at 20–30 °C; thermophilic yogurt cultures at 42–45 °C. Accessed 2026-10-09.
Tetra Pak Dairy Processing Handbook: CheeseQuark: heat-treated skim milk fermented at 20–30 °C with mesophilic cultures to a coagulum at pH 4.5–4.7 after about 16 hours, with about one-tenth of a normal rennet dose; tvorog coagulates by bacterial acidification in about 12 hours. Accessed 2026-10-09.
University of Illinois Extension: Making yogurt at homeHeat milk to 82–85 °C (180–185 °F); cool to 42–46 °C (108–115 °F); 2 tablespoons of yogurt per quart of milk; incubate 6–10 hours; ready when lightly gelled like thin pudding; refrigerate at or below 4 °C (40 °F) and eat within 14 days; use homemade yogurt as starter within 5–7 days; strain 2–4 hours for Greek-style and 8–24 hours for yogurt cheese, covered in the refrigerator; troubleshooting table. Accessed 2026-10-09.
New Mexico State University: Making homemade cheese (Guide E-216)Soft cheese holds over 45% water, is highly perishable and keeps only 5–7 days refrigerated; buttermilk or yogurt can serve as the culture. Accessed 2026-10-09.

Numbers on this page come from these sources. Where sources give a range, we quote the range rather than a single figure.

All troubleshooting guides Keep a note about this problem