Definitions: 4 types, 4 different jobs

Thermos

Double-walled, vacuum-insulated container for maximum heat retention. Usually with a screw cap and a cup-lid. The choice for winter, longer outings, or sharing with a group.

Thermal bottle

Also a double-wall/vacuum build, but with an everyday shape: lighter, sportier, with an easy lid. A balance between heat retention and mobility.

Travel mug

For city, car, and office. Focus on the lid mechanism — drink with one hand and leak-proof closure.

Food jar (thermal)

Wide mouth, made for hot meals: soups, porridge, wok. Often with a bowl or spoon.

How vacuum insulation works (and why the lid is the Achilles’ heel)

Two walls with almost nothing between them. The vacuum blocks heat transfer by conduction and convection; inner coatings reduce radiant heat. Result: your drink stays hot or cold longer.

In real life the main “leak point” is the lid — there’s no vacuum there, so lid design, gasket quality, and how often you open the container matter a lot.

Use-case scenarios: which type wins on which day

Hiking

• 0…–5 °C, short/day hike: thermal bottle 0.5–0.75 L — light, quick to open. E.g.: SIGG Thermo 0.75 L.
• Below –5 °C or a long route: thermos 0.75–1.1 L. E.g.: SIGG 1.1 L or Gemstone IBT 0.75 L.
• Very cold / for a group: 1.3–1.6 L. E.g.: Humtto 1.6 L.

Fishing

• Winter ice fishing: a large thermos + a smaller travel mug for “on-the-spot” sips. Combo: SIGG 1.1 L + Miracle 0.4 L.
• Spring/autumn in a boat: thermal bottle 0.75–1.0 L for easy drinking while moving.

Work, car, city

• Commuting and office: travel mug with a leak-proof lid. E.g.: SIGG Miracle 0.4 L or Helia 0.45 L.
• Longer days out of office: thermal bottle 0.75–1.0 L.

For kids and teens

• School/training (water): single-wall bottle — lighter and easier to wash. E.g.: SIGG Shield One 0.75 L or SIGG aluminium 1 L.
• Warm lunches: food jar 0.35–0.5 L. E.g.: Humtto 350 ml or SIGG 0.5 L.

Volume and weight: how much to bring?

Safe day formula in the cold (–5…0 °C), counting 250–300 ml per “normal cup”:

Real life: the larger the volume and the less often you open it, the longer the drink stays in the “comfort zone.”

How we test and what results usually show

A simple, repeatable test at home or in-store:

1. Preheat/pre-chill the container for 2–3 min with hot/cold water.
2. Pour in 95–98 °C water (or cold with ice), measure the start temperature.
3. Do not open for 6 h — measure; repeat at 12 h and 24 h.
4. “Real-life test”: every 2–3 h pour 50–100 ml into a cup and track the temperature drop.

Brand nuances and style: “Instagram fame” or practical everyday use?

Iconic brands tend to be heavier, bulkier, and built “for life” — great for a pickup and a picnic, but not always optimal for active hiking where every gram matters. For a European everyday–outdoor mix, compact bodies with excellent lid mechanics and available spare parts often fit better.

SIGG shines with Swiss design and a culture of details: a slimmer profile for the same volume, a broad ecosystem of lids and gaskets, and easy care over the years. If you want not just warmth but also the aesthetics of “clean lines,” this is a safe bet.

Care and hygiene: how to keep nothing “growing” in your bottle

• Before use: warm up/chill the body with water for 2–3 min.
• Regular washing: warm water + a bottle brush. Helpful: SIGG cleaning brushes/tablets.
• Gaskets and lids: remove, rinse, dry from time to time; replace when worn.
• What not to do: don’t use abrasive sponges inside, don’t use strong alkalis/chlorine, don’t leave sugary drinks closed for long.
• Carbonated drinks: allowed only in models clearly marked for it (e.g., SIGG Shield One).

Quick decision chart

FAQ — Frequently asked questions

Can I use carbonated drinks?

Only in models where the manufacturer clearly allows it (e.g., SIGG Shield One). As gas expands, you need a safe, purpose-built lid.

Can I put the container in the dishwasher?

Some lids — yes; for bodies, hand-wash is usually better to protect coatings and gaskets (see the instructions for the specific model).

Why doesn’t my thermos keep heat as long as promised?

Most often — no preheating of the container, frequent opening, too small a volume for cold weather, or a very cold environment. Try a larger volume and “preheat.”

What volume to choose for a child?

For water: 0.5–0.75 L single-wall bottle (lighter, simpler). For hot lunches: 0.35–0.5 L food jar.