The Difference Between Active and Fast Yeast

One of my favorite bakes to make at home is artisan loaves of bread. While the ingredients can be as simple as flour, water, salt, and active yeast, creating bread from scratch can be a time-consuming process. The best reward of making bread at home is not only the satisfaction of cutting into a loaf you shaped by hand, but the aroma created. Once baking, the smell of warm bread begins to fill a home, which is something candles could never replicate fully.  With so few ingredients, why does bread smell so good baking? The aroma and air bubbles inside wouldn’t be possible without yeast.

What is Yeast?

While bread is believed to have been first baked 14,000 years ago at Shubayqa, bread fermentation with beer foam began in the first century AD. While yeast was first observed in 1680 under a microscope by Antoine Van Leeuwenhoek, it wasn’t until 1857 for Louis Pasteur to understand the fermentation process. Today, we know yeast is a living single-cell fungus used in beer and bread production. There are over 1,500 species of yeast. In food production, Saccharomyces Cerevisiae is the particular species used. When combined with water and sugar, yeast ferments, converting sugar into carbon dioxide and alcohol. The production of carbon dioxide creates bubbles and rises in artisan loaves. I will focus on the yeast used for food production for this article. 

Fast-Rise and Active Yeast

If you’ve ever made fresh artisan bread, pretzels, or pizza dough, yeast was more than likely an ingredient in your shopping cart. While fresh yeast is an option, it’s hard to find and incredibly perishable. Most chefs and bakers use dried yeast, commonly sold in two forms: active and fast rise. More often than not, grocers stock yeast in the baking aisle next to the flour and sugar. If a recipe does not specify whether to use active or fast-rise yeast, you may have had a slight panic attack over which to choose. There’s minimal difference in terms of the flavor or how it will affect the bake of a recipe.

Fast and Active Yeast Vary in Size

Compared side-by-side, fast-rise yeast is noticeably more refined, has a different shape, and is lighter in color than active yeast. In addition, active yeast tends to be round, whereas fast rise yeast looks more rectangular, resembling tiny sprinkles. Beyond the variance in size and shape, there’s no difference between active and rapid rise yeast and can be interchanged in most recipes. The only difference is that fast-rise yeast is dried sooner and milled to a finer consistency than active yeast. 

Manufacturers created fast-rise yeast to eliminate activation in water before adding dry ingredients. Reducing the size of fast-rise yeast increases the total surface area, allowing for quicker activation. It’s the same idea as ice melting. If you have a pound of large ice cubes and a pound of crushed ice, the crushed ice will melt faster thanks to the increased surface area. When choosing yeast, it’s a matter of preference.  

Yeast comparison
Active yeast (left) grains are rounder. Fast rise (right) grains are smaller, and are more rectangular in shape

How to Choose Yeast

When choosing yeast, I base the decision on the recipe I’m making. If I am making pretzels, pizza dough, or a loaf of bread that will only rise for no more than a couple of hours, I use fast-rise yeast. For artisan bread that will proof overnight, I suggest using active yeast. For bread rising overnight, I find active yeast helps create consistent rise times, which can aid in timing when a bread needs to be in the oven. Honestly, if I’m making a loaf of bread that takes 12, if not 24 hours to rise, 15 minutes to activate yeast isn’t breaking my budget on time. 

While yeast activates, I’m either working on prepping another recipe step or a quick chore around the house. If you have a similar multi-task style while cooking, active yeast is likely a choice that will work for you. On the other hand, if you prefer cutting corners where possible for time efficiency, fast-rise yeast will probably be the best choice for you. 

Yeast Storage and Shelf Life

Yeast is commonly sold in two forms at grocery stores: packets and jars. Jars are a great way to save money if you bake with yeast often. If you buy a jar and need to measure out one packet for a recipe, a pack of yeast is 1/4 ounce (7 grams) or 2 1/4 teaspoons. When unopened, yeast can be stored at room temperature in a cool location away from sunlight. Once opened, jarred yeast can last in a fridge for four months, and six months if frozen. To help keep track of the use-by date, record the date opened using a permanent marker on the lid or label. 

Both Fast and Active Yeast Should be Tested Regularly

Before adding water to yeast, there is no way to tell if the yeast is dormant or dead. Yeast is alive, and many factors can influence the lifespan. The use-by date and the four and six-month rule after opening aren’t definitive. When opening yeast in August that expires in October, the yeast may not be active four months later in December. Because of this, I always recommend testing yeast before baking a recipe with or discarding yeast. 

Dead yeast will not activate once mixed. Instead of foaming, the yeast will remain i this stage.

That rule of thumb applies to both active and fast-rise yeast. The best way to test yeast is to see if the yeast activates in warm water. The good news is that testing yeast is as simple as using the recipe ingredients you already have.

Activating Yeast

When activating the yeast, the temperature is the most crucial factor. Whether in water, milk, or even beer, the temperature should be between 105 and 110 degrees Fahrenheit. If too cold, the yeast will remain dormant, and if too hot, it could die. To activate one yeast packet, at least a half cup of liquid and a teaspoon of sugar are needed. If a recipe calls for more liquid or sugar than those amounts, you can add the total quantity during activation. 

I prefer to heat the liquids in a small saucepan when activating the yeast. Once in the range of 110 to 115 degrees, I transfer it to a bowl. That way, the pan won’t continue to heat the liquid, creating pockets too hot. You can alternatively fill a bowl with warm tap water. Whichever method you choose, the water should not burn when submerging a finger. A probe thermometer is the best way to make sure the temperature is in the correct range. Once the water is within the right range, dissolve the sugar into the water. Then, lightly sprinkle the yeast over the water’s surface. Do not stir yet!  

Once Active Yeast Will Foam

If using active yeast, activation will occur within 15 minutes. For fast-rise yeast, activation can occur within five minutes. Depending on your kitchen’s temperature and humidity, clouds of yeast will develop on the bottom of the bowl and rise. Soon after, a layer of foam will appear and gather on the water’s surface. Because every kitchen differs in temperature and humidity, and the amount of water used varies, the foam produced may vary.

 

Foam formed during yeast activation
Foam formed during yeast activation

When comparing photos online, some bowls of yeast have thick foam on top, resembling a freshly poured mug of beer. Others look more like light foam on the surface. Both of those examples are of yeast that activated properly. When using less water, a thicker layer of foam will develop. With more water, the foam level will decrease. The amount of foam isn’t essential, so long as you notice bubbles rising and popping on the surface. If nothing happens after 20 minutes and the liquid temperature is correct, the yeast is no longer active. 

Is Yeast Interchangeable?

For single-rise recipes, active and fast-rise yeast is interchangeable. The two differences are whether or not activation is required and the rise time. If a recipe calls for active yeast, but you wish to use fast-rise, add the yeast into the dry ingredients without activation. If using active yeast in place of fast-rise, be sure to activate the yeast in warm liquid before adding dry ingredients. When substituting yeast in recipes, the wording of the instructions is helpful. For example, the yeast used will influence the rise time when a recipe allows the dough to rise for an hour or double in size. Rise time will increase if using active yeast and reduce if using fast rise yeast. A rough estimate is to add or reduce the rising time by 25 percent.

Try Both Yeasts Before Purchasing a Jar

Yeast is an inexpensive ingredient, with the cost of one packet averaging about 75 cents each. That cost reflects both self-rise and active varieties. Most bakers will choose to use fast-rise yeast to save time when baking. The downside of skipping the activation step is that the yeast may no longer be active. If the yeast is within the expiration date has been stored properly, the chances are it will activate. If you purchase a jar and haven’t used the yeast in a few weeks, activating your yeast before adding dry ingredients wouldn’t hurt. If you use yeast regularly, which do you prefer? We’d love to hear reasons why or your favorite yeasted recipes! 

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