There a simple technique to maximize the potency of a tincture. Because potency is directly related to the concentration of THC and other cannabinoids in your tincture, we can derive a method to saturate the glycerin with THC.
1. Take a food safe container and place a little less than the amount of hash/keif you want to dissolve inside.
2. Put enough glycerin into the container that only some of the hash/keif dissolves, but not all of it. It takes a little while so be patient with it. If there's still a little keif left and it wont dissolve, add a little more glycerin.
3. Once all of the keif has disapeared, add a little more keif, not much. Wait for it to dissolve, It may take a while. If it doesn't dissolve, you have saturated-glycerin. Which, for those who dont know, means that your glycerin cant get any more concentrated (at the same temp, pressure).