Can Gelatin Go Bad?

Since I can;t find powdered gelatin here, I buy it in the states, and since I rarely use it, I think mine is at least 6 or 7 years old and still works fine. Unfortunately there is no expiration date on it. Isn't that strange? Doesn't all food require expiration dates in the states? Anyway, it never failed me so far.

 

From what I gather there are different strengths of gran jell its given by what they call bloom count. I notice when I buy generic powder the bloom cound is listed lower the knox. I am talking 1 lb. canisters of gel powder. I have always found the danish sheet gel better then powder at least for aspics and chaudfroids.. I know here in Florida the humidity affects my sheet jell.

 

I have a jar of whole nutmeg in the cabinet that "expires" in 2015. I bought it in 1997.

 

hmmm. Well if gelatin gets exposed to moisture, that can make it less effective, but I'm more inclined to wonder if there is an ingredient in the coffee-flavored layer, or even the other layers, that is breaking down the gelatin. The enzymes in fresh pineapple and ginger root (among other fruits), for example, negatively interact with the proteins in gelatin, causing it to break down.

As I mentioned in another post regarding gels, the heating of the gelatin is the most finicky part of the process and if it's mishandled at that point, then it won't set, but you sound experienced enough to not have let that happen.

Could you share the rest of the ingredients in that recipe?

 

Are you using a different espresso bean than before for the brewed portion? I ask because a higher acidity in the bean, and therefore the final brew, could be keeping the gelatin from setting.

 

you're right, papaya is not a good choice- the protein-digesting enzymes are quite aggresive- and it would never gelate with gelatin.

First a bit of info:

As Ed mentioned, gelatine comes with very different bloom strengths, therefore your gelatin is very likely different to the gelatin in the recipe.

There is approximately 18mg/g of tannin in roasted coffee beans. The more roasted coffee beans are, the more the tannins decline.

And; powdered gelatin often has alot of other things in it, including hydrocolloids such as carageenan.

What that means: as SheChef rightly questioned; gelatin isn't too happy with tannins, they cause precipitation of the liquid, and therefore prevent gelling. The higher the gel strength the more tolerant it can be.

OR perhaps your simply not adding enough; To make a gel with gelatin self-supporting it needs to be AT LEAST 1% gelatin- however this can range up 3.3% depending bloom strength.

Lastly carrageenan although is tolerant to tannins- is a pain in the a**! And from my experience, its very difficult to work with!

Proposed solution; the most ideal solution would be to remove the tannin from the coffee- the industrial method of doing this is to form a sodium salt and pass through chloroform (!!) ... however a simple solution is to bind the tannins with something such as milk, and ensure that your coffee powder is made from FULL-ROAST beans; this will add depth and reduce tannin content.

If you've made this recipe before with IDENTICAL ingredients and amounts (measuring by weight, not volume) then it is likely that your gelatin powder has deteriorated.
If there was anything different it is likely to be your gelatin mix/bloom strength/amount and coffee roast and tannin content.

Hope that (not too scientific answer) shines some light on things.

 

I love it when people can explain some of the chemistry going on.

I like science and have some college credits in chemistry (as well as other sciences). On the other hand, when I was going to attempt to make pasta dough using lemon juice as the liquid, thinking it was a good idea, I had a couple culinary pros tell me it might not work because acids might get in the way of the protein structure.

It didn't work and they were right. You don't need to be a chemistry wiz to be a chef, of course, but I thought it was kewl that the flop was predicted.

 

Funny you brought this up. Many years ago I had to make dough for potato knishes(50 pound batches) The female chef told me to add a bit of vinegar or lemon juice to the dough to stop it from getting tough, she told me it broke down the proteins and kept dough more tender. She was right.

 

And Ed, I just looked back on my old posts, and you were the first to say "hmmm, not so sure about that" when I asked about my lemon juice-pasta idea. :thumb:

Phatch suggested lemon pepper pasta, which I definitely have to make some time. Ok sorry, back on topic eh