Question:
How long is the protein in a protein shake good after it is mixed?

I have heard that once you mix protein with water, juice, etc. that you have to drink it within a certain amount of time or the protein will disintergrate or something. Is this true? And if so, how fast do I have to drink the protein?    — mdjacobs (posted on September 24, 2003)

September 23, 2003
I know that for whey protein shakes the protein starts to dissipate after 30 minutes or if it is heated to the boiling point.
   — Carol S.

September 23, 2003
There is a protein that allows you to stir it into soups, tea, etc. I'm sure someone will let you know which one it is...it's escaping me at the moment. Also, someone else on this q and a said she emailed a protein company regarding this issue and they said that the protein does not break down. If it did, how could they make ready to drink protein drinks?
   — kathy B.

September 23, 2003
Ready-made (canned) protein drinks are different that the powdered ones you mix up yourself. Basic rule of thumb is, protein will start to break down 30 minutes after you mix it up (if it's a protein powder). That might be extended a bit if you freeze it, but still, it's best to stick with the 30-minute rule.<P>ProCel is one brand of tasteless protein powder you can mix into hot liquids (or even bake with it -- obviously the 30-minute rule doesn't hold for baking with ProCel), *but* you can't bring it to a boil or it, too, breaks down.
   — Suzy C.

September 25, 2003
hiya~ this is a myth that has floated around wls sites for quite awhile. i emailed real meals and they said that protein does not "break down" after sitting for awhile anymore than any other food would 'break down" after sitting. when you make a batch of lemonade...does it "break down" while sitting in your fridge? i also talked with the owner of a local supplement store who has a masters degree in biology and he said the same thing. the only concern you should have is if you sip off the drink and put it back in the fridge it could certainly grow bacteria and you could get sick from it (think about kids taking a swig of milk and putting the container back in the fridge --ewwww!) whey protein does "denature" if heated past boiling temperature...you can see it if you put a spoonful into boiling water -- it will not dissolve but get lumpy and you cannot stir it in. there are some soy proteins that can be mixed with boiling liquids (you need to look for one that says it on the container, generally these are "soy protein powders" NOT "soy protein shakes"). most whey protein powders can be baked with since the temperature stays lower, you can also mix them into pudding, cottage cheese and yogurt. i hope this helps some, {{hugs}} kate
   — jkb

September 25, 2003
I called the company of a protein product that I used to use (Designer Whey) and was told, it's not that the protein "breaks down" it's an issue of bacteria. She told me it didn't matter if you took a drink out of it or not that the bacteria can form even if you keep it in the fridge and don't touch it. She said their rule of thumb is 3-4 hours is all that's safe even if it's refrigerated. Since then I always try to drink it within a reasonable amount of time. Perhaps if you cannot finish a shake at one sitting you should cut the portion to something you can handle so there's little to no waste. Hope this helps.
   — Robin V.