I have used a cool method to get natural hot pepper flavor concentrated and just dosed each bottle with a proper number of drops to make the desired heat.
Google the consommé method. Basically you blend up a bunch of peppers and a small amount of water, mix it with plain gelatin, freeze it in a bowl, put frozen block in a mesh strainer over a bigger bowl in the fridge. All of the proteins will bind with the gelatin and stay jelly, while the water and heat flavor will drip into the bottom bowl. Quick, cheap, and easy extract. I then test the amount needed in an already-ready beer so I know for the fermenting batch come bottling time.