During a move I forgot which jar of ground coffee is decaf - usually I refer them by place they had. Is there any test I can perform at home to find out which jar is which type of coffee?
Only "Brew a pot and see if it wakes you up in the morning, or not." I can't think of any other test that is practical at home.
Other practical solutions -
Mix them and have half-caf until you buy new coffee.
Just buy new coffee, as if it was forgotten in the move.
And perhaps mark the containers in some way.
In the overall cost of moving, it's a small expense.
According to this empirical evidence, only two of the eight people can correctly identify the decaf. Not an academic study, but still shows that you cannot find it by flavor, in my opinion.
Otherwise, you should prepare a cup and go for caffeine test stripes. Still, those stripes will probably cost more than a few jars of coffee.