Here's What Happens If You Don't Activate Yeast Before Baking With It

We may receive a commission on purchases made from links.

If you're a bread-making beginner, you might not be aware of just how many types of yeast there are to choose from. To become a baking pro, however, yeast knowledge is important. Because if you're used to the instant yeast packets that are commonly found in grocery store baking aisles, you'll miss a key step with other varieties. Most yeasts need to be activated before you use them, or your baking will fall flat. Literally — nothing will rise, and your time and dough will be wasted. 

Tasting Table spoke to Chef Billy Parisi, owner of Parisi's Italian Kitchen in Crown Point, Indiana, about what happens if you don't activate yeast, because we want your baking to be at its best. Firstly, Parisi notes that there's one yeast you never have to activate, saying, "Instant yeast [...] is bullet-proof and will rise on anything." Instant yeast is one of the two most common types of yeast for home baking. You'll find it in most grocery stores, along with active dry yeast. 

These two yeasts look very similar — they're both dried and milled, but instant yeast granules are finer. That's why instant yeast (along with the similar bread machine yeast and rapid rise yeast) doesn't need to be activated. Despite its name, however, active dry yeast must be rehydrated and begin blooming before it can be used to bake. Parisi tells us, "The three yeasts that need activation are active, baker's, and starters." He adds that, "If they are not properly activated, then they won't rise properly."

Activating yeast basically means you're waking it up. Yes, yeasts are living single-celled organisms. Your dried mixture needs to be processed and stored well to make sure the little guys that make your dough rise stay alive and healthy. So, as well as activating yeast, the rehydration and feeding process was designed as an easy trick to test yeast before baking. This is why activation is sometimes referred to as proving. It was more important in the past, when manufacturing, packaging, and refrigeration practices weren't as advanced as they are today, but it's certainly still relevant if you're using an older packet of active yeast you're not sure about. The most important ingredient for activating and proving yeast (apart from the yeast, of course) is water. 

Depending on the instructions or recipe you're using, the correct temperature for activating yeast might be described as warm, tepid, or room temperature, but the general rule is that it can't be cold and it can't be hot. If you have a thermometer to test, aim for 110 degrees Fahrenheit (38 degrees Celsius). Dissolve one packet of active dry yeast in ¼ cup of water, and whisk the ingredients to combine. To speed things up and truly prove that your yeast will work, add a teaspoon of sugar to encourage blooming. Blooming basically just means bubbling, and with the addition of sugar, it should happen pretty much instantly once everything is properly combined. Blooming indicates that the yeast is alive and actively fermenting sugars, which produces the bubbles that will cause your bread to rise.

All yeasts sold for baking are technically baker's yeasts. The name simply refers to the variety of yeast, and baker's yeasts are cultivated specifically for baking. However, many professional bakers prefer fresh yeast to dried yeast, so fresh yeast may also be referred to as "baker's yeast." As it causes a fast rise but only lasts a couple of weeks and must be kept in the fridge, fresh baker's yeast works great in high-volume bakeries. While it doesn't technically need to be activated, many bakers choose to dissolve baker's yeast in warm water to make it easier to incorporate it into other ingredients. 

As it has a short shelf life, this is also an opportunity to check that it's still viable and will make your dough rise. Starters are also fresh yeasts, but, unlike the blocks of baker's yeast most professionals use, they're made up of wild, local yeasts. You're probably familiar with tangy sourdough bread, one of the most popular things to bake using a starter. Well, wild yeasts are what give your homemade sourdough loaf its unique flavor. 

Sourdough's nuanced and seemingly endless flavor combinations come from the fermentation that occurs as a knock-on effect of those wild yeasts feeding on sugars (sourdough starters can even get too funky if they ferment excessively). Starters have to be activated and fed regularly to stay healthy. At room temperature, twice daily feedings are needed. Starters that are kept in the fridge must be fed once a week. When you feed a starter, a large part of it first has to be removed. This is called a discard, and can be used to bake or given to a friend who wants their own starter.