01

Construction & thermal architecture

The body is drawn from a single coil of food‑grade 304 stainless steel, chosen for its corrosion resistance and inert character. Between the inner and outer walls lies a high‑vacuum layer — a gap measured in microns — that interrupts conductive and convective heat transfer. What reaches the outer wall is negligible; the surface stays cool to the touch even when the contents are near boiling.

The copper‑plated inner wall (present in select variants) adds a subtle reflective barrier, further slowing radiant heat loss. In practical terms, a freshly brewed black coffee poured at 95°C will still be above 60°C six hours later, tested in a 20°C ambient environment. Cold retention mirrors this performance: iced water topped with cubes remains below 10°C for a full working day.

“The set is not about adding features — it is about subtracting everything that doesn’t serve the temperature. A lid that seals with a quarter‑turn, a mouth that pours without a drip, a body that shows its material instead of hiding it.”

02

Lid, seal & pour geometry

The screw‑down lid is machined from the same stainless steel family, with a food‑grade silicone gasket nested inside the thread channel. When closed, the gasket compresses evenly against the rim, creating a vapour‑tight seal that keeps the flask leak‑proof even when tipped horizontally in a bag. The outer surface of the lid carries a fine radial brushing — a practical detail: it hides the micro‑scratches that accumulate with daily use.

The pouring mouth is a restrained oval cut, sized to control flow without a separate stopper. A slow pour for espresso, a quicker stream for tea — the geometry encourages a pace rather than dictating it. The set typically includes two cups with matching brushed exteriors, each nesting neatly over the lid or base for storage.

03

Surface language & daily wear

The exterior is finished with a uniform satin brushing. The horizontal grain catches light in a soft, broad band, never glossy. This choice is deliberate: polished stainless reads as formal and fragile; brushed stainless reads as utilitarian and forgiving. Fingerprints are diffused, not erased, and the surface develops a patina of fine marks that feel personal rather than damaged.

Capacity options commonly span 500 ml, 750 ml, and 1000 ml, each maintaining the same diameter‑to‑height ratio so the set reads as a family. The 500 ml slips into a car cup holder; the 1000 ml suits a long hike or a shared table. Weight is kept low by the thin‑wall vacuum construction: the 750 ml unit weighs approximately 320 grams empty.

“A good flask is a contract with temperature. It promises that a hot drink will stay hot, a cold drink will stay cold, and the outside world will feel neither. This set keeps that promise with a minimum of drama.”

04

Care & material longevity

Stainless steel’s principal vulnerability is not rust but residue. Tannins from tea, oils from coffee, and minerals from hard water can build a film that dulls the interior. A weekly rinse with warm water and baking soda, or a diluted vinegar soak, restores the bare metal surface. The silicone gasket lifts out of the lid for cleaning; it is replaceable and designed to survive years of compression cycles. No coating, no liner, no paint — the fewer the materials, the fewer the failure points.