You just solved my question.
I thought my freezer was acting up.
I made veg concentrate, froze in ice trays, then bagged.... And ended up with sludge!
Now I understand the salt is problem. Will use less next time.
I just take 1 tsp sludge out at a time!
Next I must decant chicken stock, will this be same? I used 100 gmssalt . And quirky cookings
http://quirkycooking.blogspot.co.uk/ stock recipe with a few extra veggies like fennel.