Does anyone know if adding salt makes them harder ?
A lot of recipes contains Epsom salt, which "seems" to make mine harder, but without knowing for sure whether it is the salt that is at work there... Epsom salts may make sense in bath bombs because of benefits on the skin, but in a shower steamer ? My current recipe contains those salts, but I may do without them if they do nothing for the binding and hardness.
I agree about the weather being a big factor ! It's a rainy march here in France, and I have had two failed batches this week - and a moonpress broken for applying too much pressure to force them to stay together - and a bad elbow

A lot of recipes contains Epsom salt, which "seems" to make mine harder, but without knowing for sure whether it is the salt that is at work there... Epsom salts may make sense in bath bombs because of benefits on the skin, but in a shower steamer ? My current recipe contains those salts, but I may do without them if they do nothing for the binding and hardness.
I agree about the weather being a big factor ! It's a rainy march here in France, and I have had two failed batches this week - and a moonpress broken for applying too much pressure to force them to stay together - and a bad elbow