I'm out of practice a bit:
The last few ad hoc curries are horrible. The base sauces I used in the past and the newer glasgow are great.
Some people say that burning garlic makes it bitter, but I've made a lot of singapore noodles scorching the curry powder and garlic in oil and water and that never seemed to be too bitter, actually it tastes very good this way burning the spices.
The last few curry attempts I used a lot of ginger garlic paste and tried to scorch it in the base and it tasted horrible. Then I tried just cooking it regular temp and it tasted terrible again, same as the scorched one. One was made with ginger powder/fresh garlic, one with home made ginger/garlic paste. I'm trying to get more ginger into the mix for health reasons. I'll sometimes do a teaspoon or two of ginger powder in water and it tastes fine, but in the curries it is not working.
I tasted the garlic/ginger paste raw and it's fairly bitter so the culprit is in there somewhere, just not sure if I'm overcooking, undercooking, or some other unknown.
I'm wondering if I have a bad batch or garlic here or something, but it looks fresh.