For biryani dishes, it is best to soak the extra-long grain basmati rice for 20 minutes. This removes some of the starch and also helps the rice cook so that it's fluffy and long. With this method, a 1:1 rice-to-water ratio works well, as the biryani has marinated chicken that releases plenty of liquid. Always allow the rice to cool a bit after pressure cooking and then gently fluff it up with a fork or silicone spatula