Cookbook authors sometimes tell you to add a packet of yeast to your dough mix. But how much yeast is that, exactly?
So the recipe’s calling for a packet of yeast, and you’ve got no idea exactly how much that is.
I’ve been there. And I know how frustrating it can be when an otherwise good cookbook turns out to be not as helpful as you expected it to be when you get cooking.
So let’s solve this one for ya.
In this post, we’re going to take a look at the three types of yeast that you need to know about, how much yeast is in a single packet of each, as well as how to substitute one type for another (in case you don’t happen to have the correct one in your pantry).
By the time you’re done reading, you will never, ever have to wonder about how much yeast to use again. A bold promise, I know. But stick with me, and I’ll deliver on my word as usual.
There are three types of yeast that you need to know about when it comes to baking: 1) active dry yeast, 2) instant yeast, and 3) fresh yeast, also known as “cake yeast” in the United States.
Generally speaking, active dry yeast and instant yeast can be used interchangeably. Just don’t forget that 1¼ teaspoons of active dry yeast are equal to 1 teaspoon of instant yeast.
Also, to use active dry yeast, you must first “activate” it by dissolving it in lukewarm water. In comparison, instant yeast doesn’t need to be activated, and can be added straight to the flour mix instead.
(Clearly, instant yeast, which was introduced in the 1970s, is the more convenient choice of the two. Perhaps that’s why most home bakers, me included, usually prefer it over active dry yeast.)
These two types of yeast are sold in packets, but you can also get them in 4-ounce jars. When a recipe calls for a packet—and yet you bought your active dry or instant yeast jarred—here’s what you need to know:
A packet of active dry yeast or instant yeast weighs 0.25 ounces (7 grams). That’s roughly 2½ teaspoons of active dry yeast and 2 teaspoons of instant yeast, as the latter is more compact.
In case you’re wondering, this applies to Fleischmann’s Rapid Rise and Active Dry Yeast as well as to Red Star All-Natural Active Dry Yeast and Platinum Yeast, the two brands and four varieties that grocery stores in the states tend to carry the most.
Here’s how to measure yeast when the cookbook author has done so in packets, yet you only have jars:
When a recipe calls for a packet of active dry yeast, but you happen to have jarred yeast instead, dissolve 2½ teaspoons in lukewarm water to activate the yeast, then add the solution to your flour mix.
When a recipe calls for a packet of instant yeast, but you only have jarred yeast and meet a more precise measurement than that, add 2 teaspoons of instant yeast directly to your flour mix.
But what if we’re talking about fresh yeast cakes?
Here’s how much the cookbook author probably means—depending on what side of the Atlantic ocean they live on—when they tell you to add a cake of yeast to your dough mix:
Fresh yeast cakes typically weigh 2 ounces (57 grams) in the U.S., and 1.48 ounces (42 grams) in Europe.
The good news is that you can use cake yeast instead of active dry or instant yeast. However, a few ground rules for substitution apply.
To substitute fresh yeast for active dry yeast or instant yeast, use three times more than the recipe requires. For example, if the recipe calls for 0.25 ounces (7 grams) of dry or instant yeast, add 0.75 ounces (21 grams) of fresh yeast.
To substitute active dry or instant yeast for fresh yeast, use three times less than the recipe asks for. For example, if the recipe calls for 1.8 ounces of fresh yeast, add 0.6 ounces of dry or instant yeast.
How Yeast Works
Yeast is a living, breathing creature that consists of a single cell. (In comparison, biologists estimate that the human body consists of some 37 trilling cells.)
Add yeast to flour, add water—and it starts to feed on the sugars and starches in the dough, farting out alcohol and gas bubbles as a byproduct of its feast. Trapped in the dough, those gas bubbles build up and make it rise. The alcohol, on the other hand, enriches its flavor.
This natural, biological process is called “fermentation” or, more specifically, “yeast fermentation.” As a general rule of thumb, the longer the fermentation time, the airier and more flavorsome the dough.
And, yet, you can have too much of a good thing. A dough can only hold on to so many gas bubbles before the structure that holds it together, its proteins called “gluten,” give in and start to collapse. An overfermented dough will tear apart as you shape it, and won’t rise in your oven.
The trick, then, is to let the yeast work its magic for enough time to make your homemade dough fluffy and delicious. You do this by pulling three levers:
- The amount of yeast you add to the dough;
- The humidity and temperature;
- The fermentation time.
Yeast cells thrive in the warmth and humidity of your kitchen, slow their activity down in the coolness of your fridge, and perish in the high heat of your oven.
That’s the main reason why a dough will rise for 2-3 hours in a bowl covered with a wet towel when left out on the counter and for 2-3 days when kept in your fridge. Since a dough can rise slow or fast—but flavor always takes time to develop—a longer fermentation time is better.
I’ve written extensively on the topic in an article titled “How to Make Pizza Dough More Airy.” So, if you want to up your pizza, bread, and baking game as a whole, I encourage you to go and check it out.
How Are Fresh Yeast, Active Dry Yeast, and Instant Yeast Different?
Fresh yeast has been around for a long, long time. Active dry yeast and instant yeasts are more recent inventions—and they nothing short of revolutionized home and commercial baking in the previous century.
Active dry yeast was invented by Fleischmann Laboratories in the 1940s, whose scientists were researching ways to extend yeast’s short shelf life. Instant yeast came 30 years later, when French yeast company Lesaffre launched it on the market.
Fresh yeast, also called “cake yeast” or “wet yeast,” consists of living yeast cells in a cake with 30% dry mass and 70% moisture content. Soft, crumbly, but workable, fresh yeast has a short shelf life mainly because of its high moisture content.
Active dry yeast has 92% dry mass and 8% moisture content. It’s made of dehydrated granules with dead cells on the exterior and living cells on the interior. Dissolving the granules frees the living cells from the protective coating, activating them for use.
With 95% dry mass and only 5% moisture content, instant yeast has the lowest moisture content of all types of yeast. It consists of 100% living yeast that’s been dried and dehydrated.
And that’s that, folks!
Now that you know all of this, my hopes are that you know the right amount of yeast to use for your recipe.
And that, even if you don’t have the same kind of yeast as the cookbook author, you can substitute accordingly with whatever packet or jar is in lying around there in your pantry.
As usual, don’t forget to tell me whether you found this post useful or not in the poll below. Also, share any tips, tricks, or substitution ratios of your own in the comments box as you scroll down.
All I need to know how many teaspoons in 15gramms I believe I have active yeast as it say add sugar and 150 mls of water why can’t I find the answer the nearest I got to was 5grams to a teaspoon is this correct.
Per Michigan State University’s website, 1 teaspoon = 4.2 grams. This would mean that 15 grams of yeast are roughly equal to 3½ teaspoons.
Hope this helps!