Cheese making leaves whey, the liquid drained from the curd, which is most of the milk’s volume: a 5-gallon batch of hard cheese leaves about 4.4 gallons of it. Feed it fresh to pigs as a supplement, re-heat it to 200°F with a splash of vinegar to make ricotta, use it in bread, soup and porridge, use it as a lacto-fermentation starter, or dilute it as a garden fertilizer, but never pour it into a stream.
Part of Dairy Production at Scale
Whey utilization is the practice of putting the liquid by-product of cheese making to use as feed, food, ferment starter and soil amendment, instead of discarding it.
Whey Is Most Of The Milk, So Wasting It Wastes Most Of The Volume
The parent article says cheese making produces enormous quantities of whey, roughly 9 gallons of whey per gallon of cheese. The following check uses a stated batch and shows the claim is of the right size.
Worked Example: How Much Whey
Use the rule of thumb of about 1 pound of hard cheese per gallon of milk, which is general dairy knowledge and not a wiki figure.
- 5 gallons of milk = 5 × 3.785 = 18.9 L, about 19.5 kg at 1.03 kg per liter.
- Hard cheese: about 5 lb = 2.3 kg.
- Whey by mass: 19.5 − 2.3 = 17.2 kg, which is about 16.7 L, or 4.4 US gallons. Roughly 85-90% of the milk’s volume leaves as whey.
- One gallon of cheese weighs about 4 kg at a density near 1.07 kg per liter (an assumption), and that much cheese leaves 17.2 × (4 ÷ 2.3) = 30 kg of whey, about 7.7 gallons. The parent’s 9 gallons is the same order; softer cheeses yield more cheese per milk and so less whey.
A community making 5.5 gallons of cheese milk a day (see Scaling & Scheduling) therefore has about 4.8 gallons of whey a day to handle.
Uses
Pigs. The parent article says pigs thrive on whey supplementation. Pig Husbandry lists whey among the wastes pigs turn into meat. Whey is mostly water, so it supplements a ration rather than replaces one.
Ricotta. Reheat the whey to 200°F with a splash of vinegar to capture the remaining protein, as the parent article says. Cheese Basics gives 80-90°C (176-194°F) for the same job, so a temperature in that range works; the fine curds rise and are skimmed.
Cooking. Use in bread dough, soups and porridge in place of water.
Lacto-fermentation starter. Whey is rich in lactic acid bacteria, as the parent article says, and can start a vegetable ferment; see Lacto-Fermentation. Use whey from pasteurized milk only.
Garden. The parent article says diluted whey provides nutrients and soil acidification. It is unsalted when drained before salting (salting follows the draining in the parent’s process), but whey from brined cheese is salty and can burn plants. Test on a few plants first and apply diluted, not neat.
What You Need
- Containers with lids for fresh whey, kept cool
- A heat source and a thermometer for ricotta
- Pigs, bread dough or a fermentation jar ready on the day, because whey sours within a day or two in warm weather (general knowledge)
Common Mistakes
- Letting whey sit in a warm room. It sours and spoils.
- Pouring whey into a stream or pond. Whey is rich in sugar and protein that microbes consume rapidly, using up the water’s oxygen and killing fish. This is general knowledge and not a wiki figure.
- Feeding whey as the pigs’ only food.
- Using brine whey on the garden neat.
Safety
Raw-milk whey carries raw-milk hazards, and hot whey scalds
Whey from unpasteurized milk can carry the tuberculosis, brucellosis and listeria of the milk; do not use it as a ferment starter, and treat its buckets as raw-milk equipment: wash hands and scald them after handling. Ricotta whey at 200°F scalds. Keep whey buckets covered and out of reach of children.
What’s Next
- Learn next: Pig Husbandry — turning whey into pork
- Combine with: Cheese Making — where the whey comes from