We have changed the way we make mashed potatoes. I am a fan of mashed potatoes that you can eat with a fork. They should still be smooth, but the loose potato puree that slides around on the plate and is diluted by sauce does nothing for me. We can all relate to and recall the famous Robuchon potato puree. And even though his are served in a crock, they are stable enough to hold a fluting on their surface. Potatoes need texture.
I have been observing what happens when we make mashed potatoes. After they are boiled we put them through a food mill or a ricer. Then we put them back in the pan and add the butter. At home I eliminated the step of ricing the potatoes and instead use a hand mixer with the beaters to work the butter into them and break them down. As the potatoes absorb the butter it coats the starch granules and emulsifies with the help of the steam in the pot. Despite popular belief and kitchen lore, the potatoes remain silky and smooth in spite of of using the mixer. They retain a firm texture; the potatoes are forkable. Kitchen lore says mashed potatoes need milk, cream, or some sort of additional dairy. So I would take these wonderful potatoes and add warm, not hot, liquid dairy. The potatoes would then thin out and become grainy. When I opted out of adding the liquid element we had perfect potatoes.
What is equally interesting is that when we cooled down the excess mashed potatoes we could puree them in a food processor, add water, and then reheat a fluid potato puree. I miscalculated the amount of water needed for the reheat and ended up with the aformentioned liquid potato puree. Despite my error we were onto something. Even when we put the mixture back into the food processor the potatoes did not become gluey. It was as if we had made a potato roux with the gelatinized potato and its starch. We could do anything with the potatoes without overworking them.
Now begins the process of incorporating the right amount of additional moisture to have a repeatable, reheatable, forkable mashed potatoes.