If you have seen this video, you already know that I am one of those perverts who — much like a child — drinks whole milk just for the taste of it. I love it, and years of doing my body good has helped me develop a refined “dairy palate.” If my milk is even the slightest bit sour, I can taste it.
One of my hobbies is buying too many herbs and then watching watching them wilt, dehydrate or mush out in the fridge, depending on how I’ve (incorrectly) stored them. Would placing my cilantro in a jar of water extend its life? Yes. Am I going to do that? You know...Read more
This slight off-taste, or even a stronger soured flavour, does not necessarily mean the milk is useless, though. According to a 2015 NPR interview with Dana Gunders of the Natural Resources Defence Council, pasteurised milk that’s gone sour is unlikely to make one ill:
Gunders writes, because as milk ages, it becomes more acidic, creating an environment “unfriendly to microbes that might cause illness.”
This is not the case with raw (unpasteurised) milk. Do not drink sour raw milk (fresh raw milk is dicey as it is).
But a little tartness isn’t going to hurt you. As long as your milk isn’t growing mould — or gag-inducingly rancid — acidic milk that’s a bit past its prime can be used to make many treats.
Baking is the most obvious choice, and the option best if you want to obscure the tartness — use it like you would “regular” milk, cup for cup. (Gunders is a big fan of using it in pancakes.) Just last night, I made a lemon olive oil cake with some milk that was two weeks past its “best by” date and I’d do it again. (“Best by” dates are the manufacturer’s best guess as to when the milk will taste its “freshest” — it’s an almost useless date).
The milk in question isn’t one I would want to guzzle — it had taken on a slightly yellow hue and smelled a bit sour, but it blended beautifully into the rich, already slightly tart batter. (Tasting Table asserts that soured milk is actually better than the fresher stuff, and that the extra acid helps with leavening, but the effects are kind of hard to quantify definitively.)
If you have a lot of it, sour milk can be used to marinate poultry and pork with excellent results — just add a little salt and let your meat sit in the seasoned, acidic milk overnight, then cook as usual. You can also take the whole “soured” thing to its logical conclusion and make cheese. Ricotta (precision cooking or otherwise) is never a bad choice.