Vacuum Sealing 101: A Complete Beginner's Glossary of Terms
New to vacuum sealing? Here's every term you'll run into — kPa, embossed bags, valve seals, drip trays, and more — explained in plain language.
By FreshLock Team
Vacuum Sealing 101: A Complete Beginner's Glossary of Terms
Vacuum sealing has its own vocabulary, and product listings often assume you already know it. Here's every term you're likely to encounter, explained simply.
Core Terms
kPa (Kilopascal) The unit measuring suction strength. Higher (more negative) numbers mean more air removed — -60 kPa removes roughly 95% of air, the strongest currently available in a handheld sealer.
Embossed Bag A vacuum bag with a textured, channeled surface (usually a waffle or ribbed pattern) that lets air travel to the valve during suction. Smooth bags don't work with clip-on suction sealers.
One-Way Valve The small plastic fitting on an embossed bag that air passes through during sealing, then closes to keep air from re-entering. This is what a handheld sealer clips onto.
Chamber Sealer A type of vacuum sealer (usually commercial-grade) that vacuums the entire internal chamber, including the open bag inside it — better suited to liquids than external clip-on sealers, but bulkier and more expensive.
External Sealer The category handheld and most countertop sealers fall into — suction is applied only through the bag's valve or open end, not the whole chamber.
Drip Tray A small, usually detachable and transparent component that catches liquid pulled toward the sealer during use, protecting the motor from moisture damage.
Freezer Burn Dehydration and oxidation damage to frozen food caused by air exposure — appears as grayish-white, dry, leathery patches. This is the primary problem vacuum sealing solves.
Anaerobic vs Aerobic Bacteria Aerobic bacteria need oxygen to grow; anaerobic bacteria (including some dangerous strains like botulism) can grow without it. This is why vacuum-sealed food still requires proper refrigeration/freezing — removing oxygen doesn't make food shelf-stable on its own.
Sous Vide A cooking method involving sealing food in an airtight bag and cooking it in a precisely temperature-controlled water bath. Vacuum-sealed bags are commonly used for sous vide because they eliminate air pockets that would otherwise cause uneven cooking.
Water Displacement Method A manual, machine-free technique for removing air from a zip-top bag by slowly submerging it in water so pressure pushes air out before sealing the last opening. Less effective than a true vacuum sealer but requires no equipment.
Shelf Life vs Freezer Life Shelf life refers to how long food stays good at room temperature (rarely applicable to vacuum-sealed raw food); freezer life is the more relevant metric for most vacuum sealing use cases, referring to how long frozen sealed food maintains quality.
USB-C Rechargeable A charging standard using a reversible USB-C cable rather than disposable batteries or a proprietary charging dock — the same connector used by most modern phones and laptops.
Seals Per Charge How many individual bag-sealing cycles a fully charged handheld sealer can complete before needing to recharge — a more practical spec than raw battery capacity (mAh) for comparing models.
Putting It Together
Once these terms click, most vacuum sealer product listings and reviews become far easier to parse — the specs that matter (kPa, seals per charge, bag compatibility) stop being marketing jargon and start being a real basis for comparison.
FreshLock Pro — -60 kPa, USB-C, $74.99
Free shipping over $89. 30-day returns. 1-year warranty.
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The FreshLock handheld vacuum sealer helps food stay fresh longer with one-touch valve sealing — refrigerate or freeze sealed food, and check freshness before eating.
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