What Is Active Dry Yeast?

If you are a rookie baker or a baking enthusiast, this is probably the yeast you’re most familiar with and use regularly. Active dry yeast is made up of coarse, oblong granules. It is ideal for long-term storage — if frozen, it can last to up to 10 years — but it is incredibly sensitive to thermal shock if there is a rapid change in temperature. To activate the yeast, you need to first dissolve it in lukewarm water before adding it to your baking ingredients.
What Is Instant Yeast?

Also known as quick-rise or fast-rising yeast, instant yeasts look like their active dry counterpart. The only visible difference is that the granules are smaller here. Since it has more live cells, instant yeasts are ideal for quick baking recipes as they activate much faster. Another major difference of active dry yeast is that the instant one doesn’t need to be dissolved in water before it is added to the other ingredients.
Can They Be Substituted for One Another?

Absolutely yes. They can be used interchangeably as long as you follow the specific method for use with each yeast variety. So, if you want to substitute active dry for instant yeast, you need to have a bit more time on your hands as this will mean a slower rise time (a.k.a. +15 more minutes). And, if you’re doing the opposite and replacing instant for active dry yeast, you need to reduce your rise time by 15 minutes.