Should you use purified water for sourdough baking? We tested (from left) spring water vs retail purified vs tap.
I read somewhere that you should use purified water for sourdough baking because the chlorine in tap water retards the yeast. Have dutifully done this for years without questioning. Then I noticed my purified water actually has chemicals added (baking soda and calcium chloride) “for taste”. WTF? Time for a deeper investigation!
I refreshed a dormant starter using three different water options: tap water (I live in a small city where we don’t likely have scientists on staff, so assume our water is treated according to generally accepted guidelines); Great Value from Walmart, the aforementioned “tasty” water; and Poland Water which is as pure as whatever spring it comes from. The ratio was 40g starter, 50g all purpose flour and 30g water.
The result is what you see here. The Poland Water starter rose slightly more than the others and had a lighter, airier texture. But the difference wasn’t significant. I would now say you are fine using tap water for your baking. If you’re not happy with the results it’s not the water, it’s you. (Just kidding. Most sourdough woes can be cured with an extra round of refreshing so you bake with a lively, bubbly starter.)
P.S. R/sourdough as well as some other sources say the purified water theory is bunk and distilled water (which is different than purified) actually has a negative effect because it lacks useful minerals. If you’re concerned about chemicals you can simply leave a pitcher of tap water in the open air overnight so the chlorine can dissipate.
