Are airtight containers really airtight?


Airtight containers are popular storage solutions for keeping food fresh. The key selling point of these containers is that they are supposed to keep air out and prevent food from spoiling quickly. But are airtight containers really as airtight as claimed? Let’s take a closer look at how airtight containers work and examine if they truly live up to their name.

How Airtight Containers Work

Airtight containers are designed with tightly sealed lids that prevent outside air from getting in. They are made from materials like glass, plastic, or stainless steel that don’t allow air to penetrate through the sides. The lids often have rubber gaskets that create a tight seal when closed. Some also have latch mechanisms that clamp the lid down securely to the base.

Vacuum seal airtight containers take it a step further by removing air from inside before sealing. This creates a vacuum inside the container that prevents any new air from getting in. Vacuum sealing enables longer storage times by limiting oxygen exposure.

Testing the Airtight Seal

To test how airtight a container is, you can try a few simple methods:

Water submersion test – Fill the container with water, seal it, and submerge it in a bowl of water. Look for any air bubbles escaping, which would indicate leaks.

Pressure test – Seal an empty container and squeeze it. It should not deform or crush, which shows it’s withstanding pressure.

Vacuum test – Seal the container with an indicator like a small piece of paper inside. Create a vacuum using a vacuum pump. Check if the indicator moves, showing air is still present.

Time test – Place something perishable like bread inside and leave it for several days. Check for mold growth, which would mean air got inside.

Limitations of Airtight Containers

While airtight containers can help food stay fresher for longer, they have some limitations:

Seal wears out over time – Gaskets and seal materials eventually degrade with prolonged use. This allows air to leak in and compromise the airtight ability.

Temperature fluctuations – When temperatures fluctuate drastically like freezing and thawing, it can create small air gaps for air to enter.

Lid not fully closed – Even slightly misaligned lids make containers not 100% airtight. Latches must be fully locked.

Permeability – Plastics are somewhat permeable, so very small amounts of oxygen still seep through over time.

Moisture loss – While it stops air exchange, an airtight container cannot prevent food’s internal moisture from escaping.

Tips for Maximizing Airtight Seal

While no container is 100% impervious to air, you can follow certain best practices to optimize their effectiveness:

– Inspect carefully for any cracks or damage before use.

– Clean the rims and edges to ensure no food particles or debris interfere with the seal.

– Ensure gaskets are fitted properly and replace if worn out.

– Always press down lids firmly until the latch or lock clicks fully shut.

– For vacuum seal containers, follow instructions carefully and check that the vacuum process completed fully before sealing.

– Store containers in a cool, dry place away from direct sunlight. Avoid temperature fluctuations.

– Use contents within recommended timeframe and don’t reuse containers beyond their lifespan.

Types of Airtight Food Containers

There are many different types of airtight containers available. Here are some of the most common:

Glass storage containers – Made of glass, they have airtight lids, often with rubber seals. Glass doesn’t permeate air but is breakable.

Plastic containers – Durable plastic tupperware with snap-lock lids offer budget-friendly airtight storage. Plastic is lightweight but can stain.

Stainless steel containers – Steel is impenetrable to air and does not pick up odors or flavors. More expensive but very durable.

Silicone containers – Flexible, leakproof silicone lids and containers are gaining popularity. Can withstand temperature extremes.

Mason jars – Classic glass jars with screw-on metal lids make great recyclable airtight containers. Ideal for dry goods.

Vacuum seal containers – Use a vacuum pump to remove air before sealing shut. Maintains freshness longer than other methods.

Bag sealers – Handheld or countertop appliances heat-seal bags into airtight parcels. Suitable for sous vide cooking or marinating foods.

Airtight Container Comparison

Here is a comparison of some popular airtight food container brands:

Brand Materials Special Features Price Range
Pyrex Glass bowls with plastic lids Tempered glass, BPA-free plastic lids $10 – $30
Snapware Plastic Modular containers, leakproof seals $5 – $20
Rubbermaid Plastic Affordable, variety of sizes $5 – $15
OXO Plastic Clear for easy viewing $10 – $20
FoodSaver Plastic Vacuum seal function $15 – $40

Pros and Cons of Common Materials

The material used to make airtight containers also impacts their efficacy. Here are some pros and cons of each:


– Impermeable to air and moisture
– Does not stain or retain odors
– Durable with high heat tolerance
– Easy to clean and sterilize

– Heavy and prone to breaking
– More expensive than plastic


– Affordable price point
– Durable yet lightweight
– Variety of shapes and sizes
– Leakproof lids with good seals

– Can absorb stains and odors over time
– Not as durable for high heat
– Concerns over BPA and plasticizers leaching

Stainless Steel

– Completely impenetrable surface
– Does not react with foods
– Durable, dent-resistant exterior
– Sleek aesthetic appeal

– Prone to dents and creasing
– Heavier than plastic
– Higher price point


– Flexible, tight-fitting lids
– Withstands temperature extremes
– Stain-resistant surface
– Lightweight

– Not as durable long term
– Can absorb odors over time
– Not ideal for hot contents

Maintaining an Airtight Seal Over Time

To keep your containers airtight for as long as possible:

– Avoid overstuffing containers, leave a little headspace

– Clean any stains around the rims and replace discolored sealing gaskets

– Store containers properly, avoid any dents/damage

– Replace extremely worn containers and don’t reuse past expiry

– For bags/rolls, seal using recommended settings and don’t overfill

– Vacuum seal each bag independently rather than one large batch

– Use vacuum sealing bags of the right thickness and material

– Double wrap porous items like cheese or bread before vacuum sealing

Are Airtight Containers Worth It?

For most people, investing in airtight containers is worth it for food storage. They dramatically slow the natural processes of staling and spoilage versus non-airtight options. This enables keeping home-cooked food, meal prep ingredients, snacks, produce, and baked goods fresh for considerably longer.

Airtight containers are particularly useful for:

– Storing leftovers to reduce food waste

– Keeping snacks and cereals from going stale

– Preventing produce from spoiling too quickly

– Stopping freezer burn for meats and frozen foods

– Enabling long-term pantry storage of grains, flours, coffee, etc.

– Marinating proteins or produce in a flavorful liquid

– Customizing food portions for diets and meal plans

– Protecting food quality during transport like lunches or travel

While not a magic bullet, airtight containers are an inexpensive way to stretch your grocery budget and reduce waste. Combined with proper food handling and storage best practices, they are very effective at maintaining freshness.

Tips for Using Airtight Containers

Here are some tips for getting the most out of your airtight containers:

– Let hot food cool down first before sealing to prevent condensation

– Don’t overfill containers, leave space for circulation

– Use glass or stainless steel for acidic or staining foods

– Label containers with contents and dates for easy identification

– For fridges, choose thinner plastic to allow cold airflow

– Vacuum seal in precise portion sizes for easier defrosting

– Check seals and replace worn gaskets to maintain airtight ability

– Hand wash; most are top-rack dishwasher safe on gentle cycles

– Store any ready-to-eat foods towards the front of the fridge

– Organize similar items together and use storage configurations that maximize space

Frequently Asked Questions

How long can you store food in an airtight container?

With proper airtight storage, food can typically last 1-2 weeks in the fridge, 6-12 months in the freezer, and up to 1 year in the pantry. However, perishability varies based on the specific food item.

What is the most airtight container material?

Glass and metal are more impermeable than plastic. However, well-designed plastic containers with secure lids also provide high-quality airtight seals for storage.

Do airtight containers work for pantry storage?

Yes, they are great for keeping dry goods like flour, pasta, oats, coffee, etc. dry and bug-free in the pantry for extended periods. Just be sure to clean and inspect containers first.

Can you vacuum seal already frozen food?

Yes, you can vacuum seal already frozen items to give them an extra layer of protection against freezer burn. Ensure there is no liquid or moisture present first.

Should airtight lids snap or click when closing?

They should make a clicking sound and not close easily without pressing down firmly. This indicates a tight vacuum seal. If they snap on quickly, the seal is likely compromised.


Airtight containers may not be 100% impervious to air, but when used properly, they are very effective at extending food freshness and reducing spoilage. Investing in quality airtight canisters, jars, bags and boxes is worthwhile for most homes to cut down on wasted food, save money, and eat healthier. Combined with other food safety best practices, they can help you get the most out of your groceries.

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