Royal College of Art graduate Po-Chih Lai has invented an add-on for a stove-top coffee pot that uses pressurised steam to froth up the milk (+ movie).

The Milk Brother is designed to fit into a moka pot, which works by passing steam through ground coffee.

Usually a pump is required to produce enough steam pressure to make hot milk foam, but Milk Brother simply makes use of the steam created in the coffee brewing process.

The aluminium device fits into the moka pot to create a space where the steam can be stored under pressure.

When the coffee has been poured, the pressurised steam is released into a jug of milk to heat and froth it, without the need for additional machine power.

Po-Chih Lai graduated from the RCA's Design Products course. We recently featured his design for a skateboard that can go down stairs, which is on display at Show RCA 2012 until 1 July. Course leader Tord Boontje gave Dezeen a tour of the show – see it here.

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Here's more information from the designer:

The MILK BROTHER / MOKA MILK FROTHER is inherited from the moka pot, also known as a macchinetta (literally 'small machine') or Italian coffee pot, a stove top coffee maker which produces coffee by passing hot water pressurized by steam through ground coffee. Moka pot was first patented by inventor Luigi De Ponti for Alfonso Bialetti in 1933. Bialetti Industrie continues to produce the same model under the name Moka Express.

MILK BROTHER is used to create hot milk foam via an intermediary middle valve. Hot milk foam generally relies on steam pressure which normally requires a pump, this pot employs an additional area where steam is stored under pressure‚ ready to be used for frothing milk. The combination of milk frother and moka pot provides a concise concept for a simple, integrated and lightweight solution which continues in the spirit of the original product‚ one which has inspired the public for the past 80 years. This project aims to eliminate any unnecessary tooling, design artefacts and functions. There is no pump machine, hand power, electrical requirement or extraneous function.

The vertical arrangement of the assembled product combination affords an easily comprehensible interaction and usage scenario. Steam breaks through the ground coffee from the bottom to the top, the MILK BROTHER further leverages the thermal transmission to an additional end‚ adding value and potential to the coffee making experience. Same Pot, Same Heat, More Potential.