Does baking soda go bad when exposed to air?

Quick Answer

Baking soda does not go bad per se when exposed to air, but it can lose potency over time. The shelf life of baking soda is around 2-4 years when stored properly in an airtight container in a cool, dry place. When exposed to air, baking soda may absorb moisture and odors that can affect its freshness and performance in recipes. However, it does not spoil or become unsafe to use.

Does Baking Soda Expire?

Baking soda, also known as sodium bicarbonate, has an indefinite shelf life in its dry form. So technically baking soda does not expire and go bad in the way that food products do. However, baking soda can degrade in quality and lose effectiveness over time when exposed to moisture, heat, contaminants or other environmental factors.

Some signs that baking soda may be past its prime and no longer fresh include:

  • Hardened clumps or solid blocks
  • Visible moisture clumping inside the box
  • Yellowish or brownish discoloration
  • Bitter, chemical-like smell instead of no odor

If your baking soda exhibits any of these characteristics, it is a good idea to replace it with a fresh box.

How Long Does Baking Soda Last?

An unopened box of baking soda has a shelf life of roughly 2-4 years from the manufactured date if stored properly.

Once opened, baking soda will slowly interact with carbon dioxide and humidity in the air, causing it to degrade. An opened box of baking soda has a shelf life of 6 months up to 2 years, depending on storage conditions.

Proper Storage of Baking Soda

To get the longest shelf life out of baking soda:

  • Keep it sealed tightly in its original box or container.
  • Store in a cool, dry location away from direct sunlight and heat.
  • Keep it away from strong odors and moisture.
  • Only use clean, dry utensils to scoop out the amount needed.
  • Close the box immediately after each use.

Improperly stored baking soda exposed to humidity may harden, clump and be less effective.

Why Does Baking Soda Degrade Over Time?

There are a few reasons why baking soda breaks down when exposed to air and humidity:

1. Reaction with Carbon Dioxide

Baking soda is sodium bicarbonate (NaHCO3). When exposed to carbon dioxide (CO2) in the air, baking soda undergoes a chemical reaction to form sodium carbonate (Na2CO3), water (H2O), and carbon dioxide:

2NaHCO3 + CO2 → Na2CO3 + H2O + CO2

Sodium carbonate does not have the same properties as baking soda when it comes to leavening baked goods. So this reaction reduces the effectiveness of baking soda as a leavening agent.

2. Absorption of Moisture

Baking soda is hygroscopic, meaning it absorbs water molecules from the surrounding environment. When stored in humid conditions, it will progressively absorb more moisture from the air and become hardened clumps or blocks. This reduces the leavening power, and the moisture provides the ideal environment for contaminants.

3. Absorption of Odors and Flavors

In addition to moisture, baking soda will readily absorb other odors and compounds from the air, including volatile organic compounds released from food, packaging materials and the environment. This can give baking soda an unpleasant chemical-like smell and taste.

4. Caking/Hardening

Exposed to humidity and carbon dioxide over time, baking soda particles undergo a chemical change that causes them to stick together and harden into clumps, blocks or a solid cake. Once it hardens, baking soda loses its powdery texture needed for incorporating into doughs and batters.

How to Test Old Baking Soda

To test if baking soda is still effective for baking, you can use one of these simple methods:

Vinegar Test

Add 1 teaspoon of old baking soda to 2 tablespoons distilled white vinegar. Fresh baking soda will immediately fizz and bubble when exposed to an acid like vinegar. If it has a delayed or weak reaction, then it has lost potency.

Cooking Test

Use the old baking soda to make cookies, muffins or quick breads. If baked goods don’t rise properly and have a dense, hard texture, the baking soda is no longer effectively neutralizing acid and releasing carbon dioxide bubbles.

pH Test

Test the pH of a teaspoon of baking soda dissolved in some distilled water. Fresh baking soda is alkaline with a pH between 8-9. Baking soda that has degraded will have a lower pH value.

What Happens If You Use Expired Baking Soda?

Using expired or ineffective baking soda can result in baked goods that don’t rise properly and have a dense, hard texture. However, it is not dangerous.

Since baking soda is alkaline, it can leave behind a soapy, bitter metallic taste if it has lost potency. Using large amounts of out of date baking soda can also give baked goods a more brownish discoloration.

The good news is that you can increase the quantity of baking soda to compensate if it is not fully effective. Recipes can often tolerate a higher baking soda amount up to triple the original amount.

Can Expired Baking Soda Make You Sick?

Consuming expired baking soda is generally not hazardous or toxic. Baking soda is an inherently safe food product that is added to many foods.

Its worst effects with prolonged storage include:

  • Reduced leavening ability leading to denser baked goods
  • Bitter, unpleasant metallic taste
  • Soapy flavor

These sensory issues make baked goods unpalatable but not unsafe. As an alkaline substance, baking soda can sometimes cause digestive upset if large amounts are consumed. But this would only occur with extremely excessive consumption.

One exception is for people on sodium-restricted diets, since baking soda contains sodium. Consuming large amounts could potentially increase sodium intake. Overall, however, expired baking soda does not harbor harmful bacteria or pose major health risks.

Does Baking Soda Need to Be Refrigerated?

Refrigeration is not required to extend the shelf life of baking soda. In fact, the fridge introduces more moisture which can make it degrade quicker. The optimal storage place is a cool, dry pantry or cabinet away from heat and steam.

Some people refrigerate baking soda to use as a deodorizer for things like the fridge interior. While this can help absorb odors, it will reduce the baking effectiveness more rapidly.

Signs Baking Soda Has Spoiled

Here are some signs that baking soda has gone bad and may not work as effectively:

Appearance

  • Clumped into hard blocks
  • Visible moisture clumping inside the box
  • Dull, greyish or yellow tinge rather than bright white

Texture

  • Hard and solid vs soft and powdery
  • Caked into a solid mass
  • Crystal formation on surface

Smell

  • Pungent bitter, chemical odor
  • Musty smell
  • No smell at all

Taste

  • Bitter, unpleasant metallic flavor
  • Soapy taste

Cooking/Baking Results

  • Batters and doughs don’t rise
  • Dense, hard texture
  • Dry, crumbly baked goods

What to Do With Old Baking Soda

Instead of tossing degraded baking soda, you can:

Use as a Deodorizer and Cleaner

While less effective for baking, baking soda can still neutralize odors as a fridge deodorizer, soak up carpet smells and clean countertops.

Freshen Drains

Pour some down the kitchen sink drain and garbage disposal to deodorize and prevent buildup.

Make DIY Scouring Powder

Mix with water to scrub away stains.

Clean Teeth

Make a paste with water to brush away stains from teeth.

Deodorize Pet Areas

Sprinkle in litter boxes, pet beds, carpets and other odor hot spots. The baking soda will help absorb smells without any harm to pets.

Does Baking Soda Absorb Fridge Odors When Left Open?

Yes, leaving an open box of baking soda in the fridge can help absorb unpleasant odors. As the baking soda interacts with the air, it undergoes a chemical reaction that helps trap and neutralize odor molecules.

However, an open box will lose its freshness and absorb moisture faster. For optimal odor absorption, you’ll need to change the box about every 3 months.

To extend the shelf life, keep baking soda in a covered container or mason jar with air holes poked in the lid. This allows air circulation while limiting moisture and contaminants.

Can You Use Baking Soda After the Expiration Date?

Baking soda can still be used for purposes like freshening the fridge, cleaning and deodorizing even after the expiration date has passed. Over time, baking soda absorbs odors from the fridge environment and becomes less effective at neutralizing smells.

For baking purposes, the baking soda may no longer effectively produce adequate rise and light texture. However, it’s not unsafe to use old baking soda in recipes. You may just need to increase the quantity to get the proper reaction. Test old baking soda before relying on it for baking.

As a cleaner, any bitterness or foul odors won’t affect the cleaning power. Baking soda can be used as a DIY scrubbing powder and stainless steel cleaner past the expiration date marked on the box.

How to Extend Baking Soda’s Shelf Life

To get the longest lasting freshness once opened, transfer baking soda to an airtight container like a mason jar or opaque plastic bin. Minimize air exposure by taking out only what you need then immediately sealing the container again.

Store it in a cool, dry spot in the pantry to prevent humidity and high temperatures from shortening its shelf life. Keep it far away from the stove, dishwashers and other heat sources. Letting it contact moisture is one of the quickest ways for baking soda to degrade.

When handling baking soda, only use clean, dry utensils and containers. Avoid introducing water, grease or other contaminants that can cause it to harden and clump.

Can I Use Baking Soda After the Expiration Date on the Box?

You can still use baking soda past the printed expiration date, but be aware that it may lose potency and effectiveness in recipes. The expiration date is an estimate for peak freshness and leavening power.

Expired baking soda does not pose any health or safety risks. To test old baking soda, dissolve 1 teaspoon in some vinegar. It should immediately fizz and bubble. Or use it in baked goods and check for adequate rising.

If it fails these freshness tests, you can increase the baking soda amount in recipes. Use up to 3 times the baking soda to potentially compensate for some loss in strength.

For purposes like deodorizing and cleaning, expired baking soda works just fine. The slightly diminished effectiveness when old may require you to use larger quantities.

Is Baking Soda Still Good After 2 Years?

After 2 years from the manufacturing date, baking soda held in an air-tight container in ideal storage conditions can still be effective for baking purposes. However, an opened box that is 2 years old may be past its prime.

Check for signs of degradation like moisture clumping, solid clumps, grayish discoloration and a pungent bitter odor. Perform a quick vinegar test to check potency.

If it still bubbles vigorously, the 2-year-old baking soda should still be fairly effective for baking. You may want to slightly increase the amount for insurance. If it fails the test, your best bet is to replace it with a fresh supply. But you can still find uses for it as a deodorizer and cleaner.

Can Old Baking Soda Make You Sick?

Consuming expired baking soda generally does not cause illness or toxicity. As an inherently safe food additive, it does not support microbial growth.

At worst, out of date baking soda may cause:

  • Unpleasant metallic or soapy taste
  • Dense texture in baked goods
  • Upset stomach if large amounts consumed

These effects are mainly sensory issues, not dangers from spoiled food poisoning or chemical changes.

One exception is people with kidney issues or on a sodium-restricted diet should moderate intake of old baking soda since the sodium content does not degrade over time. Overall, however, baking soda does not truly expire in a dangerous way like perishable foods.

Does Baking Soda Go Bad If It Gets Wet?

Moisture is one of the quickest ways for baking soda to degrade and lose effectiveness. If left in contact with moisture, baking soda undergoes chemical changes that diminish its leavening abilities.

Baking soda absorbs water and becomes hard, clumpy and develops a foul odor. This makes it useless for baking light and fluffy baked goods.

For this reason, baking soda should always be stored in an airtight container in a dry location away from humidity. Take care to only use dry utensils when scooping it out of the box or jar. Never return wet utensils back into the baking soda.

If the box does get some moisture in it, try to dry it out completely before resealing it. But excessive exposure to moisture will accelerate the deterioration.

Does Microwaving Baking Soda Dry it Out?

Yes, briefly microwaving baking soda can help dry it out if it has gotten moisture in it from being exposed to humidity.

To dry wet baking soda in the microwave:

  • Spread baking soda on microwave-safe plate
  • Microwave in 30 second intervals, stirring between cycles
  • Repeat until the soda appears clump-free and powdery again
  • Allow to cool fully before storing in airtight container

This can revive hardened baking soda and extend the shelf life. But it will not restore the soda to full freshness and potency. Baking soda that was left wet for a prolonged period will still deteriorate faster than fresh.

Conclusion

Baking soda remains chemically stable and safe to use after the printed expiration date. But its leavening abilities slowly decline over time when exposed to air, heat and humidity. Store baking soda properly sealed in a cool pantry to maximize freshness and shelf life.

Test old baking soda before relying on it for baking. Increase the amount if it fails a freshness test. While no longer ideal as a baking leavener, degraded baking soda still has uses as a deodorizer, cleaner and odor absorber in the fridge. Completely spoiled baking soda shows visible clumping, discoloration, foul odors and fails to react when acid is added.

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