Buttermilk is commonly used in everyday products we find at the store. Buttermilk pancakes, buttermilk biscuits – even buttermilk ranch dressing!
However, if you ask most people what buttermilk is, they’ll call it “bad milk”, or “milk and butter”… Which, aren’t exactly right, but the answer is so much more complicated than that!
What is Buttermilk?
Buttermilk is not a combination of milk and butter.
The original buttermilk that was used centuries ago was made from the leftover liquid from butter’s production from cultured cream. Today, with modern refrigeration, the cream is no longer cultured in butter making, so buttermilk is fermented afterwards to give it its patented sour taste.
Naturally occurring bacteria called Lactobacillus is what ferments the milk. The bacteria consumes the lactose sugar in the milk, creating lactic acid as its waste. Lactic acid is the compound that produces the sour taste.
As the milk’s lactose is consumed, its pH drops, which precipitates and curdles proteins that give buttermilk a sort of chunky appearance. These protein clusters are not harmful even though bad regular milk certainly has them too.
The acidity creates the tartness of the buttermilk while the precipitated protein thickens the milk, essentially curdling it.
In fact, Lactobacillus is the same bacteria used when making sourdough!
Does Buttermilk Smell Sour?
In general, today’s modern buttermilk has a sour and tangy taste, but doesn’t have a super strong sour smell. The traditional buttermilk made centuries ago, back when milk would sour quickly in warm temperatures, had a much stronger smell to it.
During the process of separating cream from milk, the traditional buttermilk was fermented naturally by lactic acid which is a form of self-producing bacteria in milk. There was little to no way of slowing the fermenting process.
How Long Does Buttermilk Last?
Luckily, the acidic environment the bacteria creates helps to prevent potentially harmful microorganisms from growing. This acid, and the low pH actually increases the shelf life of the buttermilk as well.
Because the bacteria in buttermilk creates lactic acid, as the carton sits in your fridge, it simply continues to ferment the milk, which makes the milk more sour. It can last for one to two weeks beyond the date printed on the carton.
The best way to preserve the sour smell and prolong the shelf life is to put it in a fridge immediately after used. If you try to freeze buttermilk, it can destabilize the structure and cause the separation of the milk during the thawing process.
A favorite tip of mine is that you can actually create a never-ending supply of buttermilk if you buy the right one to begin with. If you find a non-pasturized naturally created buttermilk (meaning, it is truly fermented with bacteria), you can top off the carton with regular old milk to create more buttermilk. The bacteria inside the carton of buttermilk will then ferment the new milk.
How to Make Homemade Buttermilk?
Buttermilk is really easy to make at home. However, the buttermilk we make here is NOT the same as what you’d buy at the store. We essentially use vinegar or lemon juice – both highly acidic – to curdle and “sour” the milk. We are not introducing bacteria to do the souring for us. This is essentially a shortcut to create buttermilk in a pinch.
I frequently use this method when a recipe calls for buttermilk.
- 2 cups of milk
- 1 tablespoon of Lemon Juice or White Vinegar
Combine the milk and vinegar or lemon juice in a bowl. Let this mixture stand at room temperature for 5 to 10 minutes. When you begin to see the milk curdling, the process is done.
In reality, when I need buttermilk, I usually don’t measure the ingredients out. I just pour what looks like a couple of tablespoons into however much milk I need.
This buttermilk replacement will not be as sour or as thick as regular buttermilk, but it will work for just about any recipe that needs it.