The idea is to weld together thick stainless steelplates to form a strong polyhedral sphere able to tolerate the pressure of vacuum. This is where mathematics and alcoholism meet. Immersing the distillation bulb into geothermal water (about 70°C) will yield good tasting moonshine from low cost energy. Vacuum distilled moonshine actually tastes a little better than the one distilled at normal atmospheric pressure ;-)