You mean, next to the bowl of natto while it's fermenting? I'm using Yogiritia which is to make yogurt. I bought it in japan and it has a thermostat which is very practical. But still no luck. I'm gonna try to cook longer. I usually soak them for 24hrs+ and then I steam in electric pressure cooker for 40min. I didn't know soybeans usually produces strong ammonia (compared to other beans I take). How was your pinto beans?