If you have done any amount of garlic chopping, you have probably noticed a little sprout in the middle of the clove, called the “germ”. Unlike other, pathogenic germs, this one won’t hurt you, but removing it can make your dish taste a little better (sometimes).
It seems that, in an attempt to rebrand mayonnaise, various hip food establishments insist on calling all sorts of creamy condiments “aioli”. I refuse to stand idly by, letting this go unchecked. Aioli is not, as some would have you believe “fancy mayo”. Aioli is its own, very specific thing, and it is amazing.
When your garlic is fresh and young, the germ is pale and soft, and doesn’t really affect much in terms of flavour. But as the garlic ages, the germ turns green and bitter, and it’s best to get it the heck out of there. If you’re somewhere in between — and have a sort of pale green garlic “teen” — it depends on what you’ll be doing with the garlic.
If you’re going to be leaving the garlic raw — say for an excellent aioli — it’s a good idea to always remove the germ, unless you have the youngest, freshest garlic on hand. If you’re going to be only lightly cooking the garlic, it’s also a good idea to de-germify, as just a little bit of heat won’t be enough to combat the bitterness.
But if you’re going to be cooking the heck out of the allium — perhaps roasting the whole head — it’s fine to leave the germ in, as prolonged cooking with tame the bitter beast. (If it’s sprouted, however, go ahead and plant it for delicious garlic greens.)
Removing the germ is easy — cut the clove in half (or smash it) and use your fingernail or a paring knife to pry it out, then continue with your garlic prep (and life) as usual.