How to prolong the shelf life of opened dry yeast?

Question

I bought a 500 gram pack of instant dry yeast to make pizza and I now have a slight problem. The recipe only called for 7 grams. I read in the internet that dry yeast will only remain active for 3 weeks after the packet has been opened. Is there any way to prolong this? I'm not keen on making 50 pizzas in the space of 3 weeks. The only dry yeast available was the 500 gram pack so I didn't have a choice.

Also, I live in a tropical country. Will the temperature have any effect on the dry yeast?

Answer 1

Put it in a sealed container in the back or your fridge, thats what I do. The cold will slow your yeast down about going bad, and putting it in the back will make it less subject to temperature changes. When you get somthing cold, it keeps the protiens in the cells from denaturing (in a biological sense).

Answer 2

My grandma puts it in an airtight container and puts it in the freezer. Works fine, and you can use it straight away because it doesn't actually freeze, just preserves it and keeps it fresh.

Answer 3

Yes, temperature will definitely affect the yeast, and so will moisture.  The best bet for keeping your yeast useable is to seal it in a dry, cool, dark environment.  Barring special equipment to vacumn pack it, you're best bet is a zip-lock bag with the air squeezed out, in a drawer in your fridge.