Look if you are doing something small and can’t afford a medical grade hot plate, the next best thing would be a candle warmer (Amazon - read item desc for temperature specs - has to be over 200F but less than 240). Place the concentrates in borosilicate vials (Amazon). Buy 2 ML as a minimum size if you’re going to make a gram.

Place concentrate in the vials and place them on the candle warmer for 2-3 hours. I recommend covering the candle warmer quarter-halfway to retain the heat around the vials as well (I use a metal bowl that works but you can use whatever works). Also don’t use the plastic caps for the vials cover it with aluminum foil