Types of Yeast

Discover the key differences between biological and chemical leavening agents, and how to choose the right one for your baking needs.

Yeasts can be divided in two broad categories:

✅ Biological Leavening Agents

These are living organisms (yeasts) that ferment sugars to produce carbon dioxide,making them ideal for bread and other dough-based recipes. You can check differences in the Comparison Table and use the Biological Agents Proofing Test to verify if alive and active.

The main types include:

• Fresh Yeast (also called cake or compressed yeast)
• Instant Yeast (requires proofing in warm water)
• Active Dry Yeast (can be mixed directly into flour)

These are all forms of Saccharomyces cerevisiae, a species of yeast used in baking.

✅ Chemical Leavening Agents

These are non-living compounds that release gases through chemical reactions, usually when exposed to moisture and/or heat. Typically used in are commonly used in cakes, muffins, and cookies but not excluded to be used for salthy recipes. Common examples:

• Baking Powder
• Baking Soda (Sodium Bicarbonate)
• Cream of Tartar

Understanding leavening agents in baking helps you choose the right ingredient for the texture, flavor, and rise your recipe needs.

Not sure about a term? Visit the Glossary of the terms for clear explanations.

Types of Biological Leavening Agents

Fresh Yeast

Fresh yeast, also known as cake yeast or compressed yeast, is a moist, beige-colored block with a crumbly texture and approximately 70% moisture content. Due to its high perishability, it must be stored in the refrigerator and used within a couple of weeks, though it can be frozen for extended shelf life. Professional bakers often prefer fresh yeast for its fast, reliable fermentation and its ability to produce a mild, consistent flavor in baked goods. Before use, it is typically dissolved in lukewarm water or milk, similar to the preparation of active dry yeast. This type of yeast is ideal for making artisan breads, brioche, and other traditional yeast-leavened recipes.

Usually sold in 25 gram cubes, it has a short expiration period, must be stored in the fridge, some people store it in the freezer to use it also after expiration. I recommend not to exceed too much storage in the freezer as it may not work as well as fresh.

If a recipe has Dry yeast, you can replace it with Fresh yeast using the Dry/fresh yeast converter.

Instant Dry Yeast

It is fresh dehydrated yeast. It is usually sold in 7 gram sachets.

Instant Dry Yeast (IDY), also known as Rapid-rise or Quick-rise yeast, can be mixed directly into dry ingredients without needing to be dissolved in water first. It is ideal for bread, pizza dough, and other yeast-leavened baked goods. Note that it’s still a biological leavening agent (not chemical), meaning it ferments sugars to produce carbon dioxide, which makes dough rise.

If a recipe has Fresh yeast, you can replace it with Dry yeast using the Dry/fresh yeast converter.

Active Dry Yeast

To activate Active Dry Yeast (ADY), dissolve its granules in lukewarm water (around 38–43°C / 100–110°F) and let it sit for 5–10 minutes until it turns frothy. This ensures the yeast is alive and ready to ferment sugars in the dough. It is ideal for traditional bread recipes, especially when a longer rise time is acceptable.

Note: Despite its name, Active Dry Yeast must be activated by dissolving it in lukewarm water before use.

If a recipe has Fresh yeast, you can replace it with Dry yeast using the Dry/fresh yeast converter.

Biological Leavening Agents Comparison Table

🧪 Biological Leavening Agents Proofing Test

🧂 Ingredients:

• 60 ml lukewarm water or milk (38–43°C)
• 4 grams sugar (optional, but helps feed the yeast)
• Appropriate amount of yeast (fresh, active dry, or instant)

🧾 Steps:

1. Warm the liquid: Ensure it’s comfortably warm to the touch, not hot.
2. Add sugar: Stir in the sugar to dissolve.
3. Add yeast (types of yeast):
   • Fresh yeast: Crumble it into the liquid.
   • Active dry yeast: Sprinkle it over the surface.
   • Instant yeast: Optional — can be tested the same way, but usually added directly to flour.
4. Wait 5–10 minutes: Let the mixture sit undisturbed.

🔍 What to Look For

Understanding Chemical Leaveners

Baking Powder

Baking powder is a common leavening agent used in baking. It is a mixture of a carbonate or bicarbonate and a weak acid. When moisture activates it, the acid reacts with the bicarbonate and releases carbon dioxide gas, which makes the dough or batter rise.

Baking Soda (Sodium Bicarbonate)

Baking soda, or sodium bicarbonate, is a chemical leavening agent that reacts with acidic ingredients to produce carbon dioxide gas. This reaction helps baked goods rise quickly, making it ideal for recipes like cookies and quick breads.

Cream of Tartar

Cream of tartar, also known as potassium bitartrate, is a dry, acidic byproduct of winemaking. When moisture activates it, the acid reacts with the bicarbonate and releases carbon dioxide gas, which makes the dough or batter rise.

Read in the packaging if ready to use or if needs to add Baking Soda to it. Usually the poportion is 2:1, two part of Cream of Tartar and 1 of Baking Soda.

Homemade Baking Powder Substitute

To make 10 grams of baking powder, combine:

• 2 grams baking soda
• 5 grams cream of tartar
• (Optional: 3 grams cornstarch to prevent clumping if storing)

Why Use This?

This homemade mixture mimics the leavening action of commercial baking powder by combining an acid (cream of tartar) with a base (baking soda), which reacts when moistened. It is great for people avoiding aluminum-based baking powders and useful when you run out of baking powder but have baking soda and cream of tartar on hand. It also delivers a cleaner taste, avoiding the metallic or iron-like aftertaste that some commercial powders leave behind. Many people choose it because it contains natural, recognizable ingredients.