It could well be the garlic. I used to toss garlic when I saw that sprout, because it always tasted bitter to me.
I'm so sorry about all that effort -- perhaps it's not all bitter?

I'd suspect that sprouting garlic, too. Bummer. Wonder if anyone has an antidote.

Yep....sprouting garlic....but use it and add lots of grated parmesan... and perhaps a squeeze of lemon, it will disguise the bitter taste.
Linda C

If you remove the sprouting germ of older garlic, you can use the rest. The bitterness is in the germ. So I've heard. I'd rather just get fresh garlic.

I always remove the sprout in the middle, even if its not green. I'm very sensitive to the bitterness. I can never just take a clove of garlic, whack it and mince it - I always have to take the time to remove that sprout - PITA!

I didn't use the green sprout part. I guess learning can be expensive ----- Making a large amount of pesto is expensive but that isn't the worst part. I used up the last of my last summer's frozen basil! I can't believe I never heard that before about sprouting garlic but I sure won't forget it now. (I have always used sprouting onions including the sprouts and they are fine --- oh well.)

BTW, I did use lots of Parmesan and lemon juice also. SO; Any ideas of what to do with bitter pesto?

You are all the greatest! You answered me so quickly and you are all much better than any cooking class. Thanks.

You could try adding more ground pine nuts (or walnuts if you don't have any more--I actually prefer walnuts in pesto) to see if that mellows it out a bit.

Try putting it on pasta....I think you will find it's not as bad as you think...but if not...I drop a cube into about a quart of a veggie soup...makes it into minestrone...or into chicken soup.
Or mabe a basic vinaigrette and use it for seasoning ( "ice cube" of pesto, 1/3 cup cider vinegar, 2/3 cups EVOO and perhaps 2 tsps sugar.)
Put a couple of cubes into bread...basic food processor bread:
3 3/4 cups AP flour
2 tsps salt
2 envelopes of instant yeast or the equivalant
2 cubes pesto, thawed
1 1/3 cups baby bath warm water...
More flour or water if you need it...
Raise twice, form, allow to rise and bake at 400 for 25 to 35 minutes.
Mix with butter, equal parts and spread on bread...
I'am sure there are more....but don't throw it out.
Linda C

Older basil leaves can cause bitterness too.

In October I stripped my basil plants and made it all into Pesto for the freezer. The second batch was bitter, even though it was exactly the same recipe, same ingredients and even made the same day. But the second batch was made from the lower, older leaves on the plant. I just added more lemon and EVOO and it came out just fine.

Michelle

It seems like that bitter green sprout is in most of the garlic I buy these days. No matter where I store it. I certainly don't remember it being such an issue as it is now for me. But then again, I think the cloves were much smaller years ago?

Once basil has begun to flower it turns bitter. Could it be that?

Been there...it's the olive oil.

Marilyn

I also have had bitter olive oil....but since that time I am careful to taste every bottle of olive oil that I open.
If it is the oil....nothing will cover that up.
What brand was it...where did you buy it and how long did you have it?
Linda C