When eating something like crab, garlic butter seems to be a Western thing while garlic oil is Asian.
Is it just a personal preference thing, or does it matter which one you use?
Note: Garlic butter is just melted butter with garlic, while garlic oil is oil heated to a high temperature and then poured over garlic.
I agree that they're similar, but I don't think I'd personally call them "interchangeable" in a culinary sense, just like butter and oil aren't really interchangeable in all cases.
Now, it's not like the ingredients police will arrest you for using one in a recipe instead of another. Note that melted butter is about 20% water (depending on how long you've heated it), but you're probably not baking with this stuff (though it occurs to me that it'd be an interesting addition to a salty cracker recipe).
I do not think so. Garlic butter will usually have fresh garlic in it whereas garlic oil will be oil that had garlic cooked in it. With garlic butter you're going to get a fresher, more pronounced flavor (say for putting a dollop on top of steak). Garlic oil is going to give you a deeper, more spiced flavor (say for using in a salad dressing).
At least in the two examples I gave above, they are not interchangeable. They may be in cases where you end up cooking them for a while - for instance, when sauteeing vegetables with butter/oil.
When all is said and done, it depends on the usage.
If by interchangeable you mean you can use garlic-oil when it's reported to use garlic-butter (or vice versa), then I think they are not interchangeable.
The taste of garlic-oil is different from the taste of garlic-butter; I don't think that using butter instead of olive oil for the recipe of spaghetti with garlic, oil, and red peppers would be the same.
Yes, they are interchangeable. In fact, I use both, depending on my mood. My wife hates me when I consume too much garlic (I like garlic probably too much), so I use even other options when this is the case.
If I am making a saute with yummy veggies and shrimp I love to use a garlic oil, but eating lobster I may opt for the butter. But certainly either of these would be good with either dish ;--)
One more comment. They might not be interchangeable if you are cooking something really hot, as the butter will break. In my case above, I would add some garlic butter to the cooking dish, but wouldn't rely on it for the saute. For low temp stuff, it boils down to preference.
Depends on what you are doing with it. As a condiment the major difference would be the flavor profile. Calorically and in terms of fat content most low-flavor oils are extremely similar to butter (and even olive oil has a similar number of calories, although the fat is considered healthier).
For cooking purposes, however, different oils and butter have completely different smoke points. Examples:
So you can heat these fats to different temperatures before they burn and smoke. For cooking use, you want to be careful not to burn your fat.
