I have a jar containing yeast but I'm not sure whether it is instant or active dry. Is there any way to tell the difference?
Thanks.
Baking – How to tell the difference between instant yeast and active dry yeast
bakingbreadflourfood-identificationyeast
Best Answer
You can't really tell by looking, at least not without a known sample of the same brand.
The good news is that they are usually interchangeable 1:1. Make a recipe you know well. Does it rise as you expect? Or does it take more or less time? That will most likely give you your answer.
If the dough behaves as usual, it's a good bet that you have what you usually have to make that bread. If it rises fast, it's instant yeast. If it's slower, it's active dry. For the majority of loaves, the only difference you're likely to notice is the time it takes to rise and proof.
Joe says his answer, "When it doubt, treat it as active dry yeast, and proof it first", he's absolutely right if your recipe calls for proofing active dry yeast (not all do). If the proofing seems more vigorous than usual, that's a hint that it is instant. Get it into the dough right away, don't dilly dally while your yeast expending its life force.
King Arthur Flour gets into potential substitutions more detail. One thing they noted is worth mentioning here:
So if you do both bread machine and traditional bread making, you might want to do a traditional loaf first using your unknown yeast.