Why do onions get bitter when whirred in a blender? Many Indian curry recipes include this step, but the onions are un-edibly bitter as a result.
I did some research on this for you and came up with some ideas to consider: When you grind the onions in the blender, it exposes more surface area to air which can increase bitterness. Also, the root end of the onion is said to be bitter, so you should cut it off first (if you haven't). You can remedy bitterness by soaking the onion in water and then draining well.