What is alum used for in cooking? The secret ingredient you didn’t know!

What is alum used for in cooking? This is a common question that most people often ask themselves, but few know the answer. Alum is a chemical compound that has been used for centuries in different industries, including cooking. It is a versatile substance that comes in many forms and has various uses.

In this article, we will take an in-depth look at alum, its uses in cooking, and the benefits of using it in food preparation.

What is Alum?

Alum, also known as potassium alum or hydrated potassium aluminum sulfate, is a chemical compound that is commonly used as a pickling agent, preservative, and emulsifier in cooking. It has astringent and antiseptic properties that make it an ideal ingredient for a range of uses.

Alum is most commonly available in crystal form, which is why it is also known as ‘alum crystals.’ It is a naturally occurring mineral that is found in volcanic rocks and soil, and can also be produced synthetically.

The Different Types of Alum

There are different types of alum, including:

  • Potassium Alum – This is the most common type of alum used in cooking.
  • Sodium Alum – This type of alum is commonly used as a preservative in foods like pickles and meats.
  • Ammonium Alum – This is a less common type of alum that is used in baking powder and some pickling recipes.

The Properties of Alum

Alum has various properties that make it useful in cooking. Some of its properties include:

  • Astringent – Alum has astringent properties that make it useful as a preservative and in pickling.
  • Antiseptic – Alum is also antiseptic, making it useful for treating minor cuts and wounds.
  • Emulsifying – Alum is an excellent emulsifier that helps to blend oil and water-based ingredients together in recipes.

The Uses of Alum in Cooking

Alum is used in various ways in cooking, including:

As a Pickling Agent

Alum is commonly used as a pickling agent in the preservation of a range of foods, including cucumbers, beets, and olives. Its astringent properties help to keep pickled foods crispy and extend their shelf life.

As a Leavening Agent

Alum is also used as a leavening agent in baking recipes. It reacts with baking soda or baking powder to produce carbon dioxide, which helps to make baked goods rise.

For Crispy Fried Foods

Alum can be used to make fried foods crispier by soaking vegetables in a solution of water and alum crystals before frying.

As a Food Stabilizer

Alum is an excellent food stabilizer that helps to prevent ice crystals from forming in ice cream and other frozen desserts. It is also used to stabilize whipped cream, egg whites, and other foams.

To Clarify Water

Alum can also be used to clarify water. Adding a small amount of alum to water helps to remove impurities like dirt and sediment, making the water clearer and safer to drink.

The Benefits of Using Alum in Cooking

There are various benefits of using alum in cooking, including:

Extended Shelf Life

One of the significant benefits of using alum as a pickling agent is that it extends the shelf life of pickled foods. This is because the astringent properties of alum help to keep the food crispy and prevent spoilage.

Crispier Fried Foods

Another benefit is that alum helps to make fried foods crispier. Soaking vegetables in a solution of water and alum crystals before frying helps to remove excess moisture from the vegetables, resulting in crispier and less greasy fried foods.

Clarified Water

By using alum to clarify water, you can remove impurities like dirt and sediment, making the water clearer and safer to drink. This is particularly useful in areas where the water supply is not adequately treated.

Precautions When Using Alum in Cooking

While alum is generally considered safe for use in cooking, it is important to take some precautions to avoid any adverse effects. Here are some of the precautions to take when using alum in cooking:

Avoid Overuse

Using too much alum in recipes can make the food too sour or bitter. Therefore, it’s important to use it sparingly and follow recipes that use the correct amount for specific recipes.

Avoid Ingestion

Although safe for use in pickling and baking, it is best to avoid ingesting large amounts of alum. Doing so can cause stomach upsets, constipation, and even kidney damage.

Avoid Alum on Open Wounds

Alum is a mild irritant and should not be applied to open wounds or cuts. Doing so can cause further irritation or inflammation.

FAQs About Alum in Cooking

Below are some frequently asked questions about alum and its uses in cooking:

  • Q: What is alum used for in cooking?
    A: Alum is used as a pickling agent, leavening agent, food stabilizer, and also to clarify water.
  • Q: Is alum safe for use in food?
    A: Yes, alum is generally safe when used in small amounts in cooking. However, ingestion of large amounts of alum can have adverse effects on health.
  • Q: Can alum be used in baking recipes?
    A: Yes, alum can be used in baking recipes as a leavening agent when mixed with baking soda or baking powder.
  • Q: What are the different types of alum?
    A: The different types of alum include potassium alum, sodium alum, and ammonium alum.
  • Q: Can alum be used to remove impurities from water?
    A: Yes, alum can be used to clarify water by removing impurities like dirt and sediment.


Alum is a versatile ingredient that has been used in cooking for centuries. Its various properties, including its astringent, antiseptic, and emulsifying properties, make it an ideal ingredient for a range of uses in food preparation. Whether it’s as a pickling agent, leavening agent, or food stabilizer, alum has numerous benefits that make it a useful and essential ingredient in every kitchen.


1. Murali, M., Sohail Akhtar, M., & Jamaluddin, N. (2012). Potassium alum: A review. Journal of pharmacy and bioallied sciences, 4(Suppl 2), S335–S338. https://doi.org/10.4103/0975-7406.100230

2. Sathisha, U. V., & Jayaramudu, T. (2018). Insights on the use of alum for food preservation—A review. Journal of food processing and preservation, 42(5), e13673. https://doi.org/10.1111/jfpp.13673

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