Ingredients
- 24 clean eggshells
Instructions
- Rinse each shell as you use the egg and keep them in a jar in the fridge until you have two dozen. Shells left out with albumen still in them go off quickly.
- Boil the shells in water for ten minutes. This is the step that matters: eggshells carry salmonella, and a dehydrator does not run hot enough to deal with it. Do not skip it and do not shorten it.
- Drain and spread the shells on a tray. Leave the inner membrane on — it dries with the shell and grinds in with it.
- Dry at 65 °C for 4 hours, or until a shell snaps cleanly and shows no dark patches of moisture.
- Cool completely, then grind in a clean spice or coffee grinder until it is a fine flour with no gritty pieces left. Grit is the reason a dog spits this out; it should feel like chalk dust and nothing else.
- Sift it. Anything that will not go through a fine sieve goes back in the grinder.
- Store in a sealed jar in a dry cupboard. It keeps indefinitely as long as it stays dry.
- A level teaspoon is roughly 1,800–2,000 mg of calcium. Ask your vet what your animal actually needs before you start adding it to meals — calcium is not a supplement to guess at, particularly for a growing dog or cat.
