The Earth is not dry to the center; it is composed of different layers with varying compositions and properties, including both solid and molten materials. Here's a breakdown:

• Crust: The outermost layer is a solid, rocky layer. It is not dry but contains minerals that may have water bound within their structure.
• Mantle: Beneath the crust is the mantle, a mostly solid layer. While predominantly rock, it contains minerals that can hold water in their crystal structure. It also has a partially molten layer called the asthenosphere.
• Outer Core: This layer is liquid and primarily composed of iron and nickel. The high temperatures keep it in a molten state.
• Inner Core: The Earth's center is a solid iron core due to immense pressure, despite the extremely high temperatures.

While the core is primarily metallic and doesn't contain water in the same way surface rocks and minerals do, the mantle contains minerals that hold water. A 2014 study indicated that the Earth's mantle transition zone could hold as much water as all the Earth's oceans combined.

Source: New Scientist Article on Water in the Mantle