According to the method of the present invention, a viscous initial product (P1) having both a temperature included in 5 to 70 ° C. and a viscosity of more than 100 mPa · s can be used, and provided upstream from at least one aerator (30). By the pump (20), the viscous initial product (P1) is transferred as it is to the at least one aerator, and the viscous initial product is mixed with the gas (G) injected into the aerator and continuously from the aerator. A liquid foam (P2) exiting is obtained, and the liquid foam (P2) exiting continuously from the at least one aerator is at the inlet of the processing device (40) for continuously breaking up and then drying the liquid foam. Continuously extruded, a powdery porous product (P3) having a dry material level of more than 90% is obtained.本発明の方法によれば、５～７０℃に含まれる温度と、１００ｍＰａ・ｓ超の粘度との両方を有する粘性初期製品（Ｐ１）が利用でき、少なくとも１つのエアレータ（３０）より上流に設けられたポンプ（２０）により、粘性初期製品（Ｐ１）が、前記少なくとも１つのエアレータまでそのまま移送され、粘性初期製品が、エアレータに注入されるガス（Ｇ）と混合されて、エアレータから連続的に出る液体発泡体（Ｐ２）が得られ、前記少なくとも１つのエアレータから連続的に出る液体発泡体（Ｐ２）が、この液体発泡体を連続的に分裂、次いで乾燥する処理装置（４０）の入口に連続的に押し出されて、９０％超の乾燥材料レベルを有する粉状多孔質製品（Ｐ３）が得られる。
