About the Yeast Conversion Calculator
Bread recipes are written for whichever yeast the author had to hand, and it is rarely the one in your cupboard. An American recipe might call for a packet of active dry yeast, a European one for a cube of fresh yeast, and a modern one for instant yeast by the gram. The three types are all the same organism, but they are prepared differently and contain different amounts of live yeast by weight, so they cannot simply be swapped one for one.
This yeast conversion calculator converts between instant, active dry and fresh yeast. Enter the amount the recipe calls for in grams, teaspoons or packets, choose the type the recipe uses and the type you have, and it gives the amount to use in grams, teaspoons and 7 gram packets — or, for fresh yeast, as a share of a standard 42 gram cube.
How to Use the Yeast Conversion Calculator
Enter the amount of yeast in the recipe.
Choose the unit: grams, teaspoons or packets. Fresh yeast is always entered in grams.
Choose the type the recipe uses and the type you have.
How Yeast Is Converted
1 g instant yeast = 1.25 g active dry yeast = 3 g fresh yeast
1 US packet = 7 g = 2¼ teaspoons of dry yeast
1 teaspoon ≈ 3.1 g of dry yeast
1 fresh yeast cube = 42 g (common in Europe)Step-by-Step Example
A recipe calls for one 7 g packet of active dry yeast; you have instant.
Instant: 7 g ÷ 1.25 = 5.6 g
Teaspoons: 5.6 g ÷ 3.1 g = 1.8 tspA recipe calls for 21 g of fresh yeast; you have instant.
Instant: 21 g ÷ 3 = 7 g = 1 packet = 2¼ tspThe Three Types of Yeast
Fresh yeast, also called cake or compressed yeast, is moist and crumbly. It works quickly and is prized by many bakers for flavour, but it is perishable and must be kept in the fridge, where it lasts about two weeks. It is usually crumbled into lukewarm liquid.
Active dry yeast is dried into granules with a protective coating of dead cells. It is traditionally "proofed": dissolved in warm water, often with a pinch of sugar, until it foams, before being added to the flour. It keeps for months in a sealed packet.
Instant yeast, sometimes sold as rapid-rise or fast-action yeast, is milled more finely and dried in a way that keeps more cells alive. It can be mixed straight into the dry ingredients and is a little stronger by weight than active dry yeast. It keeps well too, especially in the freezer once opened.
Proofing Yeast to Check It Is Alive
If you are not sure yeast is still active, test it before committing a whole batch of flour. Stir a teaspoon of dry yeast and a pinch of sugar into a quarter cup of warm water, around 38 °C or 100 °F. Within ten minutes it should be foamy and smell yeasty. If nothing happens, the yeast is dead and should be replaced.
Water that is too hot kills yeast. Above about 50 °C or 120 °F, yeast starts to die, and at 60 °C or 140 °F it is killed quickly. Lukewarm water — comfortably warm on the inside of your wrist — is ideal.
Adjusting Yeast for Time and Temperature
The amount of yeast in a recipe is chosen for a particular rising time at a particular temperature. You can change it deliberately. Using less yeast and letting the dough rise slowly, perhaps overnight in the fridge, develops more flavour. Using a little more speeds things up on a cold day. As a rough guide, halving the yeast roughly doubles the rising time. Salt and sugar both slow yeast down, and enriched doughs with lots of butter and sugar often need a little extra yeast to rise well.
Storing Yeast
Keep dry yeast sealed in a cool, dry place, and in the fridge or freezer once the packet has been opened; it will keep for several months. Always check the use-by date, because yeast gradually loses strength. Fresh yeast should be wrapped and refrigerated and used within about two weeks; it can be frozen, but it may lose some activity when thawed.
Yeast and Sourdough
A sourdough starter is a wild yeast culture, and it cannot be converted directly into a weight of commercial yeast. Sourdough recipes use far longer rising times and are built around the starter's activity.
Using Yeast in Cold Weather
In a cool kitchen, doughs rise slowly. Place them somewhere draught-free and slightly warm, such as an oven with only the light switched on.
Understanding Your Result
Yeast to use is the amount of your yeast that replaces the recipe's.
To measure gives teaspoons and packets for dry yeast, or a share of a fresh yeast cube.
Converted from confirms the amount and type in the recipe.
Worth knowing explains how to use the type of yeast you have.
When Should You Use This Calculator?
Following a recipe written for a different type of yeast.
Converting a European recipe that uses fresh yeast.
Using bulk instant yeast in place of packets.
Scaling a bread recipe and working out the yeast in grams.
Checking how many packets to buy.
Common Mistakes
Swapping yeast types one for one.
Using water that is too hot, which kills the yeast.
Measuring fresh yeast by the spoon.
Using old yeast without testing it.
Adding salt directly onto the yeast, which can slow it down.