If you have spent any amount of time online looking for bread recipes, you might have seen that many call for purified water or chlorine-free water. But last time I checked, history books don’t mention bottled water being around when early Egyptians were cranking out Pharaoh’s royal bread. When did tap-water get thrown out with the bath water?
I wanted to know if there really is a difference in final loaves depending on the water source. As it turns out, the water source might only matter in extreme circumstances or when working with starters. In bread making, the most important factor in monitoring water quality is the chemicals used to purify it. Chlorine levels are the most important player here as it is able to slow or end fermentation. However, most sources conclude that the levels of chlorine present in tap water in nearly every major industrialized city would not be enough to negatively impact commercial yeast activity. In fact, a test done by Modernist Bread showed nearly no difference in several bread recipes using several water types. They even performed the test with sourdough starters and found no distinguishable difference. In short, most water sources will produce a quality loaf of bread.
I guess my early Egyptian comparison was a bit unfair, since chlorine levels weren’t a concern for them. But, nonetheless, it appears as though you will be just fine using just about any clean water source you have access to while using commercial yeast. And I should clearly say I’m primarily speaking of commercial yeast here. If you are wondering about a starter, the research is much more mixed on this one, and forums are filled with debates on both sides. But, if you want to nerd out with me a bit on this we can get some common ground here. Let’s talk about what exactly chlorine does to our bread and why we might want to avoid tap-water or not.
Why Chlorine can be Bad for Bread Making
In the U.S., chlorine has been used to eliminate harmful bacteria in drinking water since the early 1900’s, which unfortunately has the effect of also killing beneficial bacteria. How it kills or neutralizes bacteria is still in debate today. One of the most prominent beliefs is that chlorine destroys cell walls which ends the bacteria’s ability to function. What researchers do know is that chlorine is not selective and has little control aside from dosage. Which means it reacts to all bacteria it comes in contact with, and will destroy or harm any bacteria when it has the proper potency to do so.
Since commercial yeast is an isolated bacteria and starters collect bacteria in the air, they can be destroyed by chlorine. Nearly all of the bread characteristics we know and love are either created or further developed by the fermentation process that takes place due to bacteria.
Why Chlorine in Tap-Water is Likely not Harmful to Commercial Yeast
Like all substances, chlorine has an effective dosage threshold. For example, vitamin C can be harmful and toxic to humans in extremely high dosages. Yet, it is beneficial for proper health when dosages are moderate. The dosage of chlorine in tap-water is controlled to neutralize the bacteria present in the water source, but it has not been shown to be potent enough to effectively harm bacteria in which the water source comes in contact with. This is why many city health organizations require commercial facilities to clean utensils with bleach (bleach being the liquid form of chlorine). The chlorine present in water is not strong enough to be an antibacterial agent in most applications.
Commercial yeast has been isolated and selected because it responds well in most environments. It is considered a robust bacteria which is not easily deterred. In order to damage it, it would take higher levels of chlorine than are typically used in water treatment facilities.
Additionally, multiple test kitchens have put tap water, hard water, distilled water, and filtered water to the test. Each test I have read shows that there isn’t a discernible difference in their fermentation process nor their finished loaves. In some situations, like in the Modernist Bread test mentioned above, this even included using sourdough starters. However, starters are widely considered to be less robust than commercial yeast, and avoiding tap-water is often suggested in order to be safe.
Even though tests have been done, and scientific literature seems to suggest otherwise, there are plenty of accounts online of bakery owners and hobbyists alike that suggest their water does impact their final products. I would be the last person to suggest that research overrides personal experience. Especially research that isn’t even conclusive in how chlorine works to begin with. I certainly can be strong willed, some might say stubborn, which means at the end of the day I’m going with what I experience to be true. In my experience, we have not had negative effects using tap-water, so we keep on using it.
HOWEVER, I also do not have a 10 plus year old starter. I’ve heard of starters that have been passed down through multiple generations. I’d do anything I could to ensure that heirloom lived on, and switching to filtered water would be a pretty simple step to have added peace of mind.
What if I do Suspect Chlorine is Doing Harm?
If you do suspect chlorine is doing your dough damage, then there are a few things you can do.
- Start using bottled water – if you do not mind the added expense you can start using bottled water, like many recipes suggest doing. Your dough is going to be safe with this option.
- Buy a water filter – again, if you don’t mind the expense, many filters on the market today will do a sufficient job in removing enough chlorine to keep your dough’s bacteria safe from harm. Just double check to make sure it does filter chlorine.
- Boil your water – boiling your water will allow for chlorine levels to burn off which will give you water that is free enough of chlorine. Just be sure to allow your water to cool to less than 120 degrees fahrenheit, as yeast will begin dying out above that temperature.
- Check your dish soap for bleach and other antibacterial substances – it could actually be the detergents used on your counters/dishes playing a role in bad dough, and not your tap-water.
Can I Use Tap-Water for Sourdough?
Sourdough is developed from a starter, which typically means there is no commercial yeast used. The fermentation process is developed by the naturally occuring bacteria and organisms that are environmental (occuring in the air and in the flour). We have heard of plenty of situations in which bakers use tap-water for their sourdough, but have also heard of situations in which their starters were slowed or even killed off from tap-water. Most starter recipes call for purified water, not only to be on the safe side of things, but also to control for flavor.
Why is Warm Water Used in Bread?
Although warm water is often called for in many bread recipes, it is not necessary. The primary reason to use warm water is to activate yeast and speed up the fermentation process. This shortens the amount of time needed for the dough to rise. This is due to the fact that yeast becomes more active as it warms up. Additionally, one of the reasons dough is kneaded is to bring up the internal temperature of the dough to create a better rise. Warm water speeds everything up, and can limit the time of kneading as well. This is especially true for active dry yeast, which is amazing, but can sometimes struggle to activate. Using warm water helps it along.