That is a really interesting site JulieS. I lived for many years in a very remote place with no electricity for refrigeration or freezing and always put a few dozen eggs away in waterglass to tide us over the period the hens weren't laying. They were useful for baking, pancakes, omlettes etc.
Before putting down I would check for hairline cracks using a carboard tube and a torch and never had a failure. I got the waterglass powder from a smallholding catalogue but which one and whether they are still going I don't know. (It was over thirty years ago!!)
So, if anyone old-ish can remember catalogues of that time I can try them.
