This thread is 12 years old. I bought new grout, changed jobs, broke my ankle, had 3 operations to fix it, moved house, bought 2 new cars and started a new side career sinde then...Unfortunately if it’s out of date it won’t be stable , sure it will mix ,it will spread and it will set ! However every time you wash it it will revert back to a soft mix and just wash out . It’s heart breaking !