When a recipe or technique calls for submerging food I worry (a lot) about that bit that sticks up above the water line. When I'm blanching something I can soothe my obsessive soul by turning a metal steamer upside down to hold the goods under water. But when storing food, say, celery root in water to keep it from turning brown, if the root's natural buoyancy keeps it above the water line, those bits that are not submerged will turn brown. BROWN! What's the point of storing it in water if it will just turn brown anyways?
My solution relies heavily on repurposing and cramming.
1. Store veg and water in a plastic container.
2. Find a lid from another, smaller container.
3. Take the smaller lid and cram it into the container until the vegetable is under the water line. The cramming friction should keep the veg in place.
4. Put the real lid on top of that and store in the fridge until a) it rots, or b) you find some other dish to use the vegetable in.