Fresh garlic vs processed
Are all garlic forms the same? Can you use fresh minced garlic, pre-minced garlic, whole peeled garlic, dried garlic, garlic powder all interchangeably and get the same results?
[Science lesson of the day] Garlic, like onions, get their characteristic flavor through an enzyme working on compounds in the garlic. Alliin in the garlic react with the enzyme alliinase to form allicin. Alliin is odor and flavorless, but allicin is what causes the characteristic pungent smell and taste of garlic. It is only formed when the cell is broken, as the enzyme combines with the alliin to create allicin. If you don't use the crushed garlic right away, these compounds break down and the flavor decreases. That's why if you mince garlic, leave it in the fridge/freezer for a long time, it will be much weaker than fresh.
- 1 fresh clove = about 2 teaspoons of minced garlic (though I personally would use a little more)
What about peeled garlic? If you look at peeled garlic, you'll see that it is slightly off white. It has a bit of a yellow tint to it. Minced garlic is practically light yellow. There's some damage to the cells that occur as the garlic is peeled and processed. The enzymatic reaction occurs and the flavors start breaking down in the store, resulting in off flavors. Rather than sprouting, like fresh garlic, pre-peeled or minced garlic produces sour flavors as it ages. There is really no substitute for fresh peeled and minced garlic from the bulb.
Dried garlic and garlic powder is processed even further and therefore much weaker per spoonful. But is there any situation you would want to use it?
Fresh peeled garlic is a hassle and time consuming. If you just need a few cloves, it's not too bad and worth it. If you need alot, you may want to go with pre-peeled and mince yourself. Some recipes even call for dried or powdered garlic. I would stay away from pre-minced. After cooking with it, I often notice a sour flavor and there isn't that pure, unadulterated garlic flavor.