If peanuts can be chopped up finely and still be dry, how come grinding them makes them pasty?
When peanuts are chopped up finely, the pieces are still relatively large and the surface area is not as exposed as when they are ground into a paste. The grinding process breaks down the peanuts into much smaller pieces, which exposes more surface area and allows the oils to be released. This causes the peanuts to become pasty.
When chopped even finely, the pieces are surprisingly still many orders of magnitude larger than the pieces when you grind them up.
Large pieces hide the oil, super tiny ones, mix with the oil.
**ELI5 the ELI5:** Grinding the peanuts releases the oils inside of them, whereas chopping them does not release as much of the oils.
They can’t. Peanut powder has had the oil removed and therefore, most of the nutritional value removed as well. Peanut powder is just the fibrous remains of ground up peanuts, not simply ground up peanuts. As others mentioned, even ground peanuts contain oil within their bits. This oil mixes with the fibrous bits to create the paste but still needs repeat mixings to keep the oil from separating from the fiber.
Peanuts have the same amount of oil in them, no matter if they’re whole, chopped, or ground. With that in mind, think of them like sponges. The inside holds the oil, and so appears dry when they’re whole, but as the peanut particles get smaller, the internal oil is pushed out, resulting in a more oily, and finally pasty, consistency.