Anybody know what might work to correct the bitterness I got from Blendtec blending fresh tomatoes, onion, jalapeño, cilantro, and garlic salsa?
If the problem is just a little bitterness on the tongue, salt is usually the best foil. If you can find out where the bitterness came from by sampling other pieces of your raw ingredients, you can try upping the ratio of other ingredients to temper it.
Advice more specific than that would require a crystal ball, I'm afraid. If it's really quite noticeable, then you're probably better off making a new batch with new ingredients.
Maybe a bit of sweet. Experiment with sugar, honey or applesauce.
My guess would probably be the garlic, if it's a fresh salsa. That's going to impart a certain amount of bitterness if everything is left raw.
A couple suggestions (I'm just spit-balling here) - maybe roast the garlic and add roasted garlic paste, instead of raw garlic (also, garlic carries botulism bacteria, which is why it is not recommended that people make homemade garlic-infused oils).
Another might be to leave out the garlic altogether. People rave about my fresh salsa, and it's just cilantro, lime juice, salt, jalapeno, sweet onion and tomato.