Lactic Acid: Fermented Whey, Lime, Oxalic Acid and Alcohol (Louradour, US Dispensatory 1907)

Whey left warm turns sour with lactic acid. Louradour's way to get the acid out: boil the whey down, take the acid up as calcium lactate with lime, then free it again with oxalic acid, which carries the lime away as an insoluble salt. A last wash in alcohol leaves the milk sugar and salts behind. Source: The Dispensatory of the United States of America (1907), Acidum Lacticum. This is pharmacopoeial lactic acid; we use it as food-grade, as ruled. The Dispensatory gives the temperature and the order of work but no amounts or times; those are stated as not given. Vessels, filter and still are ours. Picture drawn by Youblob.