Milk or whey

Milk or whey, the liquid left after milk curdles during cheese making.

Characteristics

Whey is about 93 % water, 5 % lactose and a little protein.
It may carry native lactic acid bacteria that acidify the medium by producing lactic acid.
Whey is approved in the EU as a basic substance (Implementing Regulation (EU) 2016/560).
Cow milk is approved too (Implementing Regulation (EU) 2020/1004).

Role in the preparation: Supplies lactose, proteins and lactic acid bacteria as a fermentation base in biol and lactic serums.

Caution: Do not pour surplus whey into waterways because of its high organic load, use it fresh and check local regulations before any use.

Sources: Wikipedia - Whey · EUR-Lex - Commission Implementing Regulation (EU) 2016/560 approving the basic substance whey · Commission Implementing Regulation (EU) 2020/1004 approving the basic substance cow milk

Documentary information: this is neither a recommendation for use nor a plant-protection or veterinary claim. Check your country's regulations before any use.