I got this e-mail question in my inbox...
I just have a quick question about using dried milk for drinking. I want to try mixing store milk with the powdered stuff, but how long does it stay good? If I mix up a batch does it last a week or closer to 48 hours. Everyone I have ask says I should use it with in 24 hours! If you occasionally mix it with regular milk for drinking it must last longer then that. Thanks for any help.
I scoured the internet because I wanted to know the answer too! And the sum of what I found is this...
Dry milk is just like liquid milk. When it's dry and sealed in an airtight container in a dark cupboard it can last months. But when it's reconstituted and turned back into its liquid form it reactivates and lasts just as long as store bought gallons do.
Store bought liquid milk usually has a sell date on it and can last up to 7 days past the sell date. If it passes the smell test it's still good.
It takes approximately 6 days to get from the cow to the store and then the sell by date is usually 4 to 6 days after that. Then if your milk can last up to 7 days past the sell date, we are looking at 17-19 days from cow to human before it goes sour, as long as it's been properly refrigerated.
And even if it does go sour you don't necessarily have to throw it out. Just google "sour milk" and you'll see that lots of people use it to bake with or let it curdle to make cottage cheese.
But the question of price comes up so I did a little figurin'.
An average gallon of liquid milk is between $3.50 and $4.50. (Does that sound right for your area?) It costs me $2.50 to buy enough powdered milk in the bulk section(12.8 ozs) to make a gallon. To me, that's worth it