https://cen.acs.org/articles/95/i6/Acid ... apped.htmlNonetheless, patent applications and company statements provide details about efforts to handle acid whey. A quick search of global patent applications related to the use of yogurt acid whey was conducted by CAS, a division of the American Chemical Society, which also publishes C&EN. The search revealed more than 3,500 patents, 75% of which were published in the past five years. Much of the work has focused on extracting valuable ingredients, such as proteins and lactose, from acid whey using nanofiltration and other membrane-based filtration processes.
Cow milk whey seems to have a small percentage of lactose they say about 5% and that would produce half that as alcohol and what would the efficiency be of alcohol left seems that the whey needs to have water removed to get a workable level of lactose to make viable..
Reverse osmosis or putting the whey through distillation to remove water is needed.