Mineralizing is a natural process that will occur whether you want it to or not. Once you take the soil away from sources of organic nitrogen, and get it into a relatively thin layer, so oxygen can get to it, the bacteria in the soil will mineralize the soil - oxidize the organic nitrogen compounds to nitrates. The time that takes can be excessive, so we help out by using a very thin layer, in the sun, and repeated wetting and drying, or we just bake it in the oven and let the heat do the mineralizing. The last batch I made, during a rainy spell, I only did one cycle, but the rain kept rewetting it for me. After one drying out, the soil had no smell when wet, so it was "done".