Fermenting Whey? Yes, Whey!
You’ve made some cheese (following the instructions in this story I wrote), and left behind is the whey. While many cheesemakers use the whey in place of broth in a bread dough, or as a treat for a lucky cat, I look for another fermentation from this byproduct. Such projects have included wine, mead, and even liquor (which is then used to make liqueur). Let me explain.
For any of these projects, my first step is to transform the whey into a wine. A wine made from whey, from milk? No way. Yes, whey.
Whey wines have a very long indigenous history in the Highlands and islands of Scotland, as well as Scandinavia, in Mongolia, and in Kyrgyz. In Scotland, a very low-alcohol wine called blaand (as in blond/e, not bland) was made from buttermilk. This was fermented in wooden kegs, by lactose-
consuming yeast, Kluyveromyces lactis. YouTube videos offer lessons on making blaand at around 12% ABV, but the original drink was perhaps closer to kvass, a drink made from rye bread at 1–2% ABV.
In Mongolia, a low-alcohol wine, koumiss, was made from mare’s milk. In the Kyrgyz Republic, koumiss is fermented in barrels, but in Mongolia this wine is fermented in goatskin bags.
Rather than search for Kluyveromyces lactis yeast, I ferment “on” the whey and not the whey itself. As I make cheese beginning with one gallon (3.8 L) of milk, I usually finish a pint short of that of whey. I heat the whey to about 200 °F (93 °C) to pasteurize it and eliminate the bacteria with which I inoculated the milk to make the cheese. At that temperature and at the acidity of the whey (a pH of around 5.0 or lower) a second run of cheese, akin to ricotta, may begin to form on the top of the liquid. If it does, remove the foam with a slotted spoon. Then add 2–2.5 lbs. (0.9–1.1 kg) of sugar and mix well to dissolve (this brings the volume back up to about one gallon (3.8 L). Cover the kettle and let the sweetened whey cool overnight.
If you like the idea of making a lactomel — a mead made from whey — add about 2.5 lbs. (1.1 kg) of honey, orange blossom is a good choice, in place of the sugar.
If you add 5 or 6 lactase tablets to transform the (unfermentable) lactose sugars into glucose and galactose you will increase the amount of fermentable sugar, bringing the specific gravity from about 1.090 to about 1.100. While lactose is relatively sweet, it has been determined to be only about 20% as sweet as sucrose, so definitely not as sweet as sugar.
Measure the gravity. If it is significantly above 1.100, add spring water to bring the gravity down for a more balanced wine or mead. Pour the whey into a sanitized fermenting bucket and pitch the yeast. If you intend to drink whey wine as a table wine, pitch Lalvin 71B or QA23 wine yeast at this point.
As a table wine or mead, add tannin as if this was a fruit wine (about ½ tsp. per gallon/3.8 L) and loosely cover the fermenter with a cloth. After a few days of active fermentation, rack the wine into a carboy. Now seal with a bung and airlock. The wine will need to age about nine months or more before you can really taste its fruity nature, which is very similar to the French sweet wine Sauternes.
If, however, you are interested in making liquor or liqueurs from your whey, pitch 1 Tbsp. of baker’s yeast. This will take off like gangbusters within a few hours. No need to add tannin or acid. Rack to a carboy after a few days and seal with a bung and airlock. Fermentation will be complete in 3 weeks.
From there, you can distill the wine. The result, for all intents and purposes, is vodka. As such, I’ve used it as a base to make liqueurs.
