Because as juicy and delectable as fresh berries are, they're also impossibly delicate. Luckily, we have a simple trick for keeping your precious berries fresh and mold-free for as long as possible this summer–or anytime of year. Credit: Adventure_Photo/Getty ImagesWhy Does Vinegar Keep Berries Fresh? By washing berries in a mixture of white vinegar and water, you can make your berries last longer in the fridge. Store berries in paper towel-lined container.