Even if we say "for a while," this work cannot be completed within several hours, it takes usually three to four weeks until heat caused by friction is totally radiated and the rice settles down.
「しばらく」と言っても数時間単位で済む作業ではなく、摩擦熱が放散しきって完全に米が落ち着くまで通常3週間から4週間はかかる。