Distilled water should not be used in sourdough production. It is more acidic than tap water, so it is sometimes considered a better choice for feeding sourdough starters. However, distilled water is only 0.5 pH more acidic than tap water. A sourdough starter will drop to around 4.2ph, so using slightly more acidic water has minimal benefit. Besides, in the creation of distilled water, minerals alongside the impurities are removed, which are essential for sourdough bacteria to multiply. Without minerals, the starter will be weak and slow to rise.