I use lemon juice in a bowl of water. Sorry I can't give you a ratio. You can also use a product called Fruit Fresh. I thinks it's just dehydrated citrus acid. I don't soaked them any longer than it takes to do the peeling and cutting. I have a tool that peels, cores and slices them with a few turns of the handle. Once I'm done I dump the water and place them on the dehydrator trays. That's it. You can also dehydrate in the oven at a very low temp but I like the counter top convenience better.