Hospitality · The edge of physics
KegSight — cellar keg and syrup fill-level sensing
Steel kegs shield their insides from the signal completely — physics says no.
Not claimed
We publish what we will not claim — that is how you can trust the rest.
Why the physics says no
A steel keg acts like a perfect shield: WiFi cannot get inside, so it cannot read the liquid level in there. Plastic containers and bag-in-box syrup would work, but the flagship steel keg does not. We would rather say so plainly than sell it.
In the physics: Liquid (eps_r~80) versus headspace gas (eps_r~1) inside a container radically changes how paths reflect, refract, and delay around/through it; as level drops, specific CIR taps shift delay and amplitude because the effective dielectric boundary inside the propagation volume moves. Bag-in-box and plastic vessels are directly visible; steel kegs are read via the changing external scattering geometry and resonance of the liquid-loaded shell.
Reviewer's verdict: Steel kegs are a Faraday enclosure — external CSI cannot read internal liquid level, and 'external resonance of the liquid-loaded shell' is not a real commodity-CSI observable. Only bag-in-box/plastic vessels are viable, not the flagship steel keg.