I'd toss it and make my own. It's so easy to do it:

Ingredients:
â¢Milk (just under one cup)OR, even better, cream
â¢1 Tablespoon white vinegar or lemon juice

Preparation:
1. Place a Tablespoon of white vinegar or lemon juice in a liquid measuring cup.
2. Add enough milk to bring the liquid up to the one-cup line.
3. Let stand for five minute. Then, use as much as your recipe calls for.

I use buttermilk that is months old ! All you have to do is pour it out into a cup and taste/smell it. It lasts WAY over the date in my experience...spanning decades. The thickness and richness of the cultured buttermilk that you purchase is very different than the product you make with vinegar and milk so beware of adding it to a recipe as it will not be the same consistency.

Yogurt is another product that keeps well past any date on the package . Hope this helps c

Shake it up before you open it. It will un-separate and be fine to use.

I would shake it, smell it and taste it, if it smells okay. I'd use it with no hesitation if it didn't smell/taste bad.

I agree, I'd shake it and smell it. I'm betting it's still fine, it lasts a LONG time past the "best by" date.

I've used yogurt instead of buttermilk, when I didn't have buttermilk and it works well too.

Annie

I'm so glad to see I'm not the only one who uses expired buttermilk. I use it in fits and spurts so sometimes a carton will sit for sometime. I have an expired carton in the fridge now that I will use in pancake batter this weekend. I agree that a commercial carton is better than the milk/lemon juice (or vinegar) concoction. I'm loving Ci_lantro's suggestion on extending store- bought to make your own.

Like the others mentioned, buttermilk can be used well past the date. Yogurt, and sour cream, I use as well after expired, if necessary.

I use 2/3 cup yogurt and 1/3 cup milk successfully in my bran muffins as I seldom have buttermilk on hand.

Ci_lantro, I've never heard of growing your own buttermilk! Sounds very cool, and worth a try!

The milk and vinegar or lemon juice mixture makes sour milk.
While it can be used in place of Buttermilk,
in my experience,
there is a pretty big difference,

Rusty

I bought buttermilk during the thanksgiving holiday for biscuits. Not sure why since DH has always used yogurt for his biscuits. A whim i suppose. When i cleaned out the fridge from odd
things gone wrong...elder bits of things gone off, like a lost slimy cucumber, (ick), i dealt with the buttermilk...it had separated, liquid poured out into the sink. The solids were thick on the bottom...not for me, me-no-shake-n-use. Maybe fine but did not smell 'fresh'.
I'll stick to yogurt and make a milk from it with a bit of water in a container and shake. We always have non-fat greek yogurt and find i can use it for everything needing milk or cream...
Makes the shopping list easier since we never use or buy regular milk or cream.

It depends for what you're using it to see a "difference". Like Annie, you could use yogurt, or sour cream, or this substitute. In baking, it's not enough difference to buy a different ingredient. I wouldn't consider pouring it and drinking it (as many are wont to do here in the South), calling it the same thing, but it works well enough.

I know this is an old thread but as a buttermilk lover I wanted to offer some comments.

I pay little attention to expiration dates on buttermilk. I usually keep a culture going but do restart with purchased buttermilk after a few months. Right now I am using a purchased gallon with a date of May 30 and it is still fine. It sat
unused for a while while my wife was in the hospital and we weren't home to use it.

Some argue for a difference in cultured and churned buttermilk and there may be a difference in the bacteria culture but taste is essentially the same. Home churned buttermilk was made from the natural culture of bacteria present in the raw milk. Pasteurization kills these bacteria thus supermarket milk on its own will not make good buttermilk. I purchase whole milk by the gallon and if not used by a reasonable time after the expiration date has passed I add a cupful or more of purchased buttermilk or my culture. I often push milk well past the expiration date by shaking the jug at every use.

I was raised on raw milk. My mother always kept a Jersey cow and had a crock of milk clabbering in a warm corner at least once per milk. I was used to butter extracted from clabbered milk and it took me a long time to develop a taste for sweet cream butter, though I know some farm women had crank butter churns to make butter from cream. Mother churned with a dasher in the crock, usually flipping pages in the Sears or Wards catalog as she churned. When the butter came she centrifuged it by twirling the dasher handle (probably fashioned from a broomstick) between her palms. The whey was squeezed from the butter and it was washed several several times with water before being chilled enough for molding.

The buttermilk was refrigerated, fairly thin to begin with and getting thicker with age. When it was deemed too thick it went out to a trough for the chickens. This is where the cultures may differ, purchased buttermilk doesn't thicken so quickly and the whey doesn't separate as much.

Ci_Lantro, would 1% milk work in the growing of buttermilk, or would it have to be at least 2% in order to work?

Eddie you are so lucky to have those memories! Milk is a whole different animal now days from what it was back then. I know milk borne illness is a terrible thing, but we threw out some of the baby with the bathwater!

I haven't tried 1% but think it has palm oil or something added to keep it from feeling like water in tour mouth. I have used powdered milk to make buttermilk, in fact the recipe was on the box. Then powdered milk prices went higher than fresh milk so I stopped.

BTW milk borne illness was never heard of when I was a kid. Our cow had to be checked for TB once per year and wore an ear tag. My allowance was earned by delivering milk to a couple of homes up our street. Fifteen cents a quart for (sweet) milk and 10 cents for buttermilk. I think the dairy lobby caused raw milk to be banned.

This post was edited by Eddie_T on Thu, Aug 21, 14 at 13:43