I found fresh cake yeast (called Levure Boulangère Fraîche in French) difficult to find in stores whereas in France you can get it at any big stores. It is usually the yeast I use mostly for raised dough like brioche or croissant dough.
Due to the limited availability of the cake yeast, like many bakers before me, I had to adapt to US and use dry yeast in place of cake yeast. Once rehydrated, dry yeast is as performant and efficient as cake yeast. Surpringly here is no difference at all in the result.
Here are few tips to store your dry yeast (directions from the manufacturer):
- Unopened Dry yeast package
Stored it in a cool, dry place. Can be also stored in the refrigerator or freezer
- Opened Dry yeast package
The yeast must be refrigerated (4 months) or frozen (6 months) in an airtight container
Also I made this conversion chart for you that I hope will come handy to determine yeast equivalence between Cake yeast and Dry yeast.
Finally my last advice is to use Dry Yeast at room temperature before using (let it sit at room temperature for 30-45 minutes before using).