What is Bean Juice Made Of? The Science of Aquafaba

November 24, 2025 •

4 min read

The liquid drained from a can of chickpeas, often discarded as waste, is actually a remarkably versatile ingredient known as aquafaba, or bean juice. Scientifically, this liquid is a mixture of water, proteins, and carbohydrates that leaches from the legumes during cooking, giving it unique functional properties like foaming and emulsifying.

Quick Summary

Bean juice, commonly called aquafaba, is the starchy, protein-rich liquid remaining after cooking legumes. Its unique composition of water, proteins, and carbohydrates allows it to act as a potent vegan substitute for eggs, offering emulsifying, foaming, and binding capabilities in both sweet and savory dishes.

Key Points

Composition: Bean juice, or aquafaba, is made primarily of water, proteins, and starches that leach from legumes like chickpeas during cooking.
Functionality: Its unique molecular properties allow it to act as an emulsifying, foaming, and binding agent, making it a powerful vegan egg substitute.
Applications: Aquafaba can be whipped into meringues, used to make vegan mayonnaise, and serves as a thickener in soups and stews.
Source: It can be sourced from the liquid in canned beans or made at home by boiling dried legumes.
Usage: Three tablespoons of aquafaba can generally replace one whole egg in a recipe, with slight variations depending on the application.
Variation: Different beans and preparation methods affect the concentration and reliability of the liquid, with chickpeas and white beans generally providing the most stable results.
Sustainability: Repurposing bean juice as an ingredient reduces food waste and offers a valuable culinary tool for plant-based and conventional cooking.

The Core Components of Bean Juice

At its most basic, bean juice—specifically aquafaba—is a byproduct of the cooking process for legumes, typically chickpeas or other white beans. When beans are simmered in water, their starches, proteins, and soluble plant solids migrate from the legumes into the surrounding liquid. This creates a viscous solution with a unique molecular structure that mimics the properties of egg whites. The primary constituents of this liquid are water, a small amount of leached proteins (around 1%) and carbohydrates, which include both sugars and soluble fibers. Commercially canned aquafaba also contains added salt, which acts as a preservative and adds flavor.

The Viscosity Factor

During cooking, the starch molecules released from the beans swell and ultimately form a gel-like network that contributes to the liquid's viscosity. This thickened consistency is crucial for its functionality in many recipes. The more viscous the liquid, the more stable and effective it tends to be when whipped into a foam. This is why reducing thinner, homemade aquafaba is a common practice to achieve better results for tasks like making meringues.

The Foaming and Emulsifying Properties

The ability of bean juice to foam and emulsify is what makes it a revolutionary vegan ingredient. The soluble proteins and saponins (a class of plant chemicals) act as natural surfactants, reducing the surface tension of the liquid and allowing it to trap air bubbles. When whisked, this trapped air creates a stable foam that can be used in place of egg whites for items like meringues, marshmallows, and mousses. The emulsifying properties, on the other hand, allow aquafaba to bind oil and water together, creating creamy textures perfect for vegan mayonnaise, aioli, and cheese substitutes.

Culinary Applications for Bean Juice

Bean juice is a highly versatile ingredient in both sweet and savory cooking. Its uses extend far beyond simple broth.

Whipped Topping & Meringues: The most famous use for aquafaba is to whip it into stiff peaks to create a fluffy meringue or whipped cream topping. Sweeten with powdered sugar and flavor with vanilla for a perfect dessert topping.
Vegan Mayonnaise: Aquafaba's emulsifying power is ideal for creating a creamy, stable vegan mayonnaise by blending it with oil, lemon juice, and other seasonings.
Binding Agent: Un-whipped aquafaba can be used as a binder in many baked goods, such as cookies, brownies, and muffins, where it replaces a whole egg.
Thickener for Soups and Sauces: The starchy liquid adds body and creaminess to soups, stews, and sauces, providing a richer mouthfeel without adding dairy.
Cocktails: For a foamy head on classic cocktails like a whiskey sour, aquafaba is an excellent vegan alternative to egg whites.

A Comparison of Canned vs. Homemade Aquafaba

While both canned and homemade versions of bean juice can be used, there are key differences in their properties due to preparation and processing methods.


Feature	Canned Aquafaba	Homemade Aquafaba
Consistency	Highly consistent and viscous due to industrial processing methods and sometimes added preservatives like calcium chloride.	Viscosity can vary significantly depending on the bean type, cooking time, and water ratio.
Flavor	Can have a saltier or more distinct flavor due to added salt and processing. Taste may also vary by brand.	Generally has a more neutral flavor, especially if cooked without salt and aromatics.
Convenience	Immediately available and requires no cooking, making it very convenient.	Requires soaking and cooking dried beans, which takes more time and effort.
Reliability	More reliable for whipping into foams due to standardized viscosity and processing.	Can be less reliable and may require reduction by simmering to achieve the desired consistency.
Control	Less control over sodium levels. Opt for low-sodium or no-salt-added varieties if preferred.	Full control over sodium levels and flavor profile by choosing whether to add salt or other aromatics.

Conclusion: Making Use of the 'Liquid Gold'

What is bean juice made of? It's a simple, yet elegant combination of water, starches, and proteins extracted during the cooking of legumes. More commonly known as aquafaba, this versatile liquid has revolutionized vegan baking and cooking, offering a simple and cost-effective substitute for eggs. Instead of pouring this 'liquid gold' down the drain, you can save it for making light meringues, creamy mayonnaise, or thickening your next batch of chili or soup. Its functionality is a testament to the fact that valuable ingredients can sometimes be found in the most unexpected places. For more information on how to use aquafaba in your cooking, the vegan cooking community offers a wealth of resources and recipes, including those on the official Aquafaba website.

Note: While aquafaba from chickpeas is the most popular, liquid from other legumes like white beans can also work, though results may vary.

Frequently Asked Questions

Aquafaba is the specific term for the viscous, starchy liquid from cooked legumes like chickpeas, used primarily as an egg substitute. Regular bean broth refers more broadly to the liquid left after cooking any beans, used for flavoring soups and stews.

Yes, the liquid from canned beans is perfectly safe to consume. It is a mixture of water, salt, and starches from the beans, and can be used in cooking to add flavor and body to dishes.

To make aquafaba from dried beans, first soak the beans, then simmer them in fresh water until tender. Drain the cooking liquid and reduce it by simmering until it achieves a desired, more viscous consistency. Let it cool completely before using.

Leftover aquafaba can be stored in an airtight container in the refrigerator for up to a week. For longer storage, you can freeze it in ice cube trays and then transfer the frozen cubes to a freezer bag.

While liquid from most legumes will work, aquafaba from canned chickpeas and white beans is generally preferred, as it has a more neutral flavor and provides the most stable results when whipped.

A general guideline is to use three tablespoons of aquafaba to replace one whole egg, or two tablespoons to replace one egg white. However, amounts may need to be adjusted based on the recipe and desired consistency.

Compared to eggs, aquafaba has very little nutritional value, containing only a few calories and a negligible amount of protein and fat per tablespoon. Its primary value lies in its functional properties rather than its nutritional content.