First of all, it's worth noting that kitchen ovens all have the same square shape, with the roof and grill at the top, and the hearth at the bottom.
Between the two, there are a number of positions, or levels, usually 3 or 4, into which a grid can be inserted, allowing you to choose whether you want to bake in the middle, or towards the top or bottom.
These positions are often numbered, from 1 (lowest) to 4 (highest) on the side of the oven entrance.
Bottom in oven (1)
This is the lowest position in the oven, bringing
the underside of your dish closer to the heat coming from the oven hearth.
You want the heat to come from the underside of your dish, because it needs to cook more from below.
This is the case, for example, with tarts/dishes with puff pastry in the bottom, which need a lot of heat to cook properly.
You may also need to move the top of the dish away from the heat of the vault, to prevent it from coloring too much or even burning, and here too you position it low in the oven.
In the middle (3)
This is the standard baking position, where your dish or mold is placed at roughly equal distance from the hearth and vault, and baking is not accentuated either above or below.
Top of the kiln (4)
This is the highest position in the oven, bringing
the top of your dish closer to the heat coming from the oven's vault, or perhaps even the grill.
You do this when you want to get the best heat from the top of the dish, for au gratin for example.
You may have noticed that I didn't mention position 2, as it's an intermediary between 1 and 3 (of course), and allows you to dose things down a little and do "not so low".
Some remarkable points
If we had to sum it all up, we could say that :
- It's always interesting to play around a little with where the heat is going to come from to cook your dish, simply by positioning it in your oven.
- If you don't know where to position your dish, simply place it in the middle.
- If you're baking puff pastry, a thick cake, or anything else that needs to be cooked well on the bottom, put it on the bottom.
- If you need to brown a dish, put it in the top oven.
- There's nothing to stop you changing levels as you cook, finishing by raising a dish to bring it closer to the grill, for example.
To sum up: It's always a good idea to control the cooking time in your oven, by putting a dish in the oven at a higher or lower setting, depending on the type of dish.