Sounds like the heat may be the problem! I use the Paul Kirk's method by sprinkling it onto a un-greased cookie sheet. Spreading it all out, then letting it air dry for about 2 hrs. I then shift out the lumps before adding it to my rub...
I use the Paul Kirk method only I thought I invented it. I spread the brown sugar out in a large baking sheet and let it sit out for 24 hours. I stir occasionally. That works when the humidity is low like here in N Texas. When I was in the Army decades ago, I was stationed on the Island of Okinawa. Being only 1/2 mile from the sea, humidity was very high. There, we put white rice grains in everything that was dispensed in a shaker like salt (or dry rubs). So what I am suggesting is that you make your dry rub and then mix in a generous amount of white rice then close the lid on your shaker. The rice would theoretically absorb the moisture. The rice could then be sifted out later.
i dried mine out in the oven on the lowest setting for about 10 mins then crushed what i could up with the back side of a spoon, i still had a few clumps and went out and got a flour sifter and that took care of em
I've dried brown sugar on a cookie sheet in the oven on it's lowest convection setting for about 10 minutes then turn the oven off and leave it in until the sugar is dry to my liking. The run it through a sifter to eliminate lumps.
It's often too humid to lay out at room temperature but I suppose if the A/C was cranked it would pull more humidity out of the air.
I was watching one of the food network shows and the recipe called for brown surgar.The lady had one of the type jars that had the wire latch that closed and sealed it to store the sugar.The "thing" here was a small stone that was inside she said could be purchased easily.I think it was the same material as plain clay pots but she said if soaked in water it kept the sugar from clumping.When she measured the brown surgar it was as loose as plain white sugar.
The trouble with brown sugar is the fact that as soon as moisture is introduced into the air, brown sugar get tacky again, Heck, so I just mix her up with the rest of those rub spices, and generally the granules of the other spices will keep the brown sugar loose, otherwise, I just give the jar a couple thwacks against the palm of my hand that will knock em loose! :roll:
Carl, I do the same thing.. just mix in as it is and rub the rub between my hands .. I store mine is a plastic zip lock bag .. If I don't want dried out brown sugar I usually find a box that wasn't closed all the way and then I have a brick of dried out brown sugar.