It’s pretty easy to know when your sea moss gel has gone bad, the smell is strong and you might see mould growing in the jar. Also, if you get that far, the taste will change as well.
Trust me, you’ll know when it’s gone bad!
If you notice your sea moss smelling bad, then you have to just throw it away. It can make you really sick.
A way to avoid this is once you make a batch, bag it up into smaller portions and store the portions in the freezer. Sea moss can be frozen so if you mess your measurements up and end up with more sea moss gel than you expected, just store enough for a week or two in the fridge that you can use every day, and then bag rest up and store that in the freezer.