I bought a pack of yeast and stored it for weeks. I didn’t open it, yet. I bought it long before using it because I was active doing trial and error while making bread for daily breakfast.
The just few days ago, I opened the pack and used the yeast. I was confused. My flour was high quality one, other ingredients were also as usual, and the humidity was ok but why didn’t the proofing go well?
After using the yeast 3 times, I decided to test it. The composition when testing was 1tbs yeast + 1 tbs sugar + luke-warm water.
First test: the proofing was very very slooooooooow. I compared it with yeast that I previously opened long before this pack. Even the older instant yeast showed bubble faster than the later yeast. Both took time to show bubble, which I can understand it’s normal with older instant yeast…It’s ‘older’…you know…but as for the newly opened package, the speed almost matched the ‘older’ one is kind of weird.
I’m trying to think positive. May be it’s the weather. I really don’t want to throw away the newly opened instant yeast.
Then, I bought NEW instant yeast. Yes, I bought a new pack. I tested the new instant yeast along with the died-suspected yeast.
Second test: I set timer for 14 minutes. Same composition was used. When I checked the result, this was what happened!
The left one is the NEW instant yeast I just bought that day. The right one is the ‘died-suspected’ instant yeast. The brands are different but both are my regular yeast. I used it interchangeably. In fact, I use the right instant yeast brand more frequently. So, I know both have quite same quality and good for the recipe I have. My bread was usually ok using the right one. It was even ok when I used older-age instant yeast.
I had a problem with proofing long time ago but I managed to solve it by ‘pre-activating’ it (even it’s instant, I give activating booster, too) before using. How to do it? It’s pretty same as testing the proofing. It was really helpful. Yet, you might find different composition in google about pre-activating yeast. You can check out in google using searching words: activating yeast. When I first learning about it, I actually not using dry-yeast activating technique; I used ‘testing’ the yeast technique instead. That’s why, there is sugar. That was the technique I found.
But to the died-supected instant yeast, I don’t think, the pre-activating method can help. It’s sad but I think, I have to throw away the whole package.
Conclusion:
Just don’t buy and store the instant yeast at home. Just buy it, right before you are using it.
Even if we use it later and not opening the package, seems the instant yeast quality can deteriorate somehow. The stores have inventory management, so, they shouldn’t store too long. The problem is when we are as user store it. We might store it too long and even if it was intact in the packaging, still, the damaged/early expired risk is real.