What is the difference between a silicone and a plastic food storage container?

Silicone is a flexible, rubber-like material, and in food storage it usually appears as a lid, a gasket or a sealing ring rather than as the container body. Plastic is the rigid molded material that most container bodies are made from, and in airtight sets the two are combined: a plastic or metal body with a silicone seal doing the sealing work. The difference that matters in practice is which part of the container each material forms, and what the maker states about that part.

The picks in Best Food Storage Containers for Five Different Kitchens show the split clearly. Two picks are plastic bodies sealed with silicone, one is a plastic body with a built-in vent, and two are stainless steel bodies closed with silicone or leak-proof lids. No pick on that fact sheet is a fully silicone container, so this site has not compared one.

Where silicone actually appears in these containers

In the Vtopmart Airtight Food Storage Containers with Lids, 24 pcs, Black, the maker describes side-locking lids with a silicone gasket that make the containers airtight. The body itself is durable plastic, BPA free, and the set comes in four sizes: 6 Tall Container (2.5quart), 6 Large Containers (1.8quart), 6 Medium Containers (1.5quart) and 6 Small Containers (0.7quart). The silicone here is a thin ring, not a structural part.

The JSCARES 40 PCS Food Storage Containers with Lids Airtight follows the same pattern. The maker states that the airtight seal is enhanced by food-grade silicone rings, and that the containers are made from upgraded food-grade materials that are BPA free. The set measures 9.7 inches x 9 inches overall and holds 20 containers in two shapes, with capacities the maker lists from 8 OZ to 51 OZ.

The Sustainable Containables Stainless Steel Food Storage Containers with Clear Platinum Silicone Lids, Airtight, Leakproof 18/8 (304) Food Grade SS Nested 3Pk 20/30/40 oz Plastic-Free takes the silicone further. Here the lids themselves are flexible platinum silicone, and the maker states they are plastic-free, BPA-free, BPS-free and phthalate-free. The bodies are 18/8 (304 food grade) stainless steel. The set measures 5.46 inches wide, 7.53 inches deep and 2.21 inches high and weighs 1.34 pounds.

What the plastic body brings to a storage container

A plastic body is rigid, so it holds its shape when stacked and does not need an outer frame. The Rubbermaid Brilliance Tritan Plastic Food Storage Containers BPA Free Airtight Lids Ideal for Lunch Meal Prep & Leftovers Set of 5 (3.2 Cup) uses crystal-clear Tritan, which the maker describes as stain-resistant and odor-resistant, with built-in vents for microwave heating without removing the lid. The set includes five 3.2-cup containers and matching lids, totaling 10 pieces.

Rigidity also lets a maker mold in latches, vents and lock mechanisms. The JSCARES set lists 4 enhanced rounded lock mechanisms, durable non-slip bottoms and stackable, nestable shapes. The Vtopmart set uses a modular design so the containers stack on top of each other, and every container in the set shares the same lid, which the maker states makes them easy to wash, dry and reuse.

What plastic does not do on its own is seal. Every plastic pick on the fact sheet relies on a silicone gasket or ring to reach its airtight or leak-proof claim, which is why the two materials are usually described together rather than as alternatives.

The third option: metal bodies with silicone lids

Two picks move the body to stainless steel and keep silicone for the lid or seal. The CLWVPCOT 10 Pack Stainless Steel Food Storage Containers with Leak-Proof Lids, 34oz Reusable Metal Meal Prep Lunch Boxes, Stackable, BPA-Free, Dishwasher Safe for Snacks, Fruits & On-the-Go Meals states 304 stainless steel bodies, each with a 34 oz capacity, and outer dimensions of 7.4×5.31×2.16 inches with an inner size of 7×4.72×2.16 inches. The maker lists a weight of 0.26 pounds.

The Sustainable Containables set pairs 18/8 (304) stainless steel with clear platinum silicone lids that the maker states create an airtight seal. The maker also states the containers are freezer, oven and dishwasher safe, and that the set nests for compact storage. The three containers are listed at 20, 30 and 40 oz.

For a reader comparing silicone against plastic, these metal picks are the closest thing on the fact sheet to a silicone-forward design, and even they use silicone only as the lid. A container molded entirely from silicone does not appear among the five picks, so this site has not compared one.

What the makers publish, and what they do not

Material claims are published in detail. Vtopmart states BPA-free durable plastic. JSCARES states BPA-free food-grade materials and food-grade silicone rings. Rubbermaid states BPA-free Tritan. CLWVPCOT states food-grade 304 stainless steel and BPA-free construction. Sustainable Containables states 18/8 (304) stainless steel and plastic-free, BPA-free, BPS-free, phthalate-free silicone lids.

Thickness, shore hardness and temperature limits for the silicone parts are not published by any of the five makers on the fact sheet. Nor do the makers publish the grade or thickness of the plastic walls. Where a maker publishes a dimension, it is the assembled container: the JSCARES set at 9.7 inches x 9 inches, the CLWVPCOT containers at 7.4×5.31×2.16 inches outer, and the Sustainable Containables set at 5.46 inches wide, 7.53 inches deep and 2.21 inches high.

Weight is published for three picks: Vtopmart at 3.0 pounds for the 24-piece set, JSCARES at 0.66 pounds, CLWVPCOT at 0.26 pounds and Sustainable Containables at 1.34 pounds. Rubbermaid does not publish a weight for its set.

How to read the difference when choosing

If the sealing is what you care about, the silicone part is the one to check, and all five picks describe a silicone or leak-proof sealing element. If rigidity and stacking are what you care about, the body material decides that, and the plastic picks describe stackable, nestable or modular designs while the metal picks describe nesting sets.

If you want to avoid plastic in the container itself, the Sustainable Containables set is the only pick whose maker states the containers and lids are plastic-free, with stainless steel bodies and platinum silicone lids. The CLWVPCOT set is stainless steel with leak-proof lids but the maker does not state that the lids are silicone-free.

Beyond those points, the makers do not publish figures that would let you compare silicone and plastic on durability or heat tolerance, and nobody at Lush has used these products. The comparison rests on what each maker states about materials, seals and published dimensions.