Should you use bottled water to feed a sourdough starter

Should You Use Bottled Water To Feed A Sourdough Starter?

Should you use bottled water to feed a sourdough starter
Updated on
November 17, 2022
Gareth Busby
Gareth Busby

A lot of home bakers run towards the water being at fault for an unhealthy starter. Although it isn’t always at fault, unsuitable water can produce a weak or unusable starter. So should you use bottled water to feed your starter? Use this guide to find out.

Either tap water, spring water, bottled water or filtered purified can be used to feed a sourdough starter. As important minerals are removed from distilled water it’s not recommended. Any drinkable water is suitable for a starter. But, if local tap water is heavily chlorinated bottled water should be considered.

Does water really matter?

Well yes, and no. For those of us with great tap water, the subject doesn’t need tinkering. There may be some difference in the rate of fermentation and the possibility of a better flavour by changing water, but differences are often negligible. Changing the flour or fermentation technique will have a much greater effect.

But if the water you use is causing your sourdough starter to not rise, it really matters!

Aside from being drinkable (you don’t want harmful bacteria), one of the leading factors in water choice is the number of minerals it contains. As water passes through rocks, woodlands and gulleys it latches onto some of the materials it passes.

The importance of mineral content

Common rocks and metals such as chalk, magnesium and iron are found in water. Some of these minerals are diluted at water processing plants alongside the removal of any harmful bacteria. When taking water from a well or local spring, the materials remain. And this is why it can come out of the tap cloudy. Providing regular contamination checks are made, this water is fine to drink, although, too much mineral activity can cause problems when making a starter.

See minerals need to be digested by the yeast and broken down into carbon. The carbon will eventually be consumed by the culture to produce gas and other products in the sourdough fermentation process. The result of a starter fed with high mineral water is a higher rise and a more robust culture, but this takes time. If mineral content is too high a new starter can take so long to process the minerals that it becomes too much of a challenge. Too many unwanted particles weaken the culture and it simply gives up.

If you are off-grid or don’t have a safe water source nearby you might use a revers-osmosis filter. This strips all bacteria and minerals to make it safe to drink, but it’s less effective for sourdough. Without minerals, a starter tends to create small bubbles quickly initially but doesn’t often progress to a mature one. This doesn’t mean it can’t be used to make a quality starter though, as I explain below.


Water boards must process the dirty, often sewage-ridden (thanks Boris!) river water into clean drinking water. In part of the cleaning process, chlorine is used to kill off bacteria. If high doses are required the chlorine in the water will also destroy the necessary lactic acid bacteria (LAB) that are cultured in the starter. Effectively, starters made with heavily chlorinated water will not rise.

How to remove chlorine from tap water

If you suspect that chlorinated water is holding your starter back the simplest thing you can do is smell it. If the water smells like chlorine, it probably contains a lot of chlorine, but it doesn’t mean that it can’t be used.

Chlorine evaporates out of the water when exposed to airflow. So to remove chlorine from your tap water simply pour the water into a jug or container and leave it to stand for 30 minutes before use.

To speed up the process you can opt to boil the water for 5 minutes in a saucepan. As temperature is an important factor in breadmaking, this method is usually not worth doing as boiling water takes more than 30 minutes to cool.

Using bottled water to feed a starter

If you can’t wait for chlorine to evaporate or suffer from a high or low mineral count in your water, bottled water is an obvious solution. The extra step makes it harder to find motivation just using bottled water is a sensible choice regardless of the expense.

If you buy water to drink it can be tempting to store all of them in the refrigerator but try to keep one bottle at room temperature. Starter cultures operate best at warmer temperatures so try not to use it right out of the fridge.

Using water filtered water to feed a starter

Many of us have a water filter to make tap water more pure and healthy. If your water is particularly hard or chlorinated you’ll need a ​​granular activated carbon filter. These are fitted to the mains supply (and expensive) so you won’t find that chlorine is removed from the Britta one you keep in the fridge.

A domestic water filter may provide benefits to a sourdough starter, but many bakers don’t notice a difference. Some even say that the removal of minerals harms the starter. It certainly won’t remove chlorine.

In professional bakeries, a water filtration system is definitely worth considering. Sand and other dirty deposits will block the steam jets in the oven. It can also damage the water cooler, a device used to provide an accurate water temperature for mixing.

Using purer water also introduces bacteria which will negatively affect the shelf life of the bread. Because of the long fermentation process, this is less of an issue in sourdough bread but it is a consideration for yeast-levained baking.

Is hard water better than soft water for a sourdough starter?

It is best to use hard water to feed a starter as the minerals in the water will be broken down and consumed by the yeast or lactic acid bacteria. This provides a slower, yet higher rising starter which can be used to make better risen and more tasty bread.

Is spring water better than tap water for sourdough?

If using spring water you can be safe in the knowledge that it is chlorine-free. As chlorine can destroy healthy microorganisms and bacteria spring water can make better bread than tap water. Springwater also contains more minerals as the water passes through rocks before surfacing on the ground. These provide more food to enhance a sourdough starter.

Using reverse osmosis water to make a sourdough

As the minerals and microorganisms are removed during the filtration process the water is very sterile. This isn’t great for making a culture of bacteria and yeasts, but we can add some minerals back in to boost it.

Don’t use ordinary white all-purpose flour. Use stone-ground or organic bread flour as they contain more minerals than ordinary flour. Wholegrain flours such as whole wheat, rye or spelt will also provide a nice enhancement making a healthy starter more likely.

Using tap water to feed a sourdough starter

If you don’t suspect a problem with your tap water, there probably isn’t one. If your starter is not rising as you expected take a look at my why is my starter not rising guide? The majority of the world’s best bakeries utilise water from the tap so you likely can too!

Bottled water in sourdough starter – Conclusion

What I’ve found when it comes to water choice in bread is that the effects of water choice are often overplayed. What doesn’t work for some bakers isn’t an issue for others, so what are your findings? Let other readers know in the comments below.

Frequently asked questions about using bottled water for feeding a sourdough starter

Should I use purified water for making sourdough bread?
Use the same water in your starter for your sourdough bread. It’s not usually essential to use purified water but if tap water destroys your starter, don’t use it for your bread.
Can I feed my sourdough starter with tap water?
Providing the tap water is drinkable and not overly chlorinated you can use it to feed your starter. It saves buying expensive bottles or filters and makes perfectly good sourdough bread.
Can I use distilled water in my sourdough starter?
Distilled water is almost pure H2O as it contains less than 10 PPM of total dissolved solids. The lack of minerals makes it not recommended to drink. It can be used to make a starter but the lack of microorganisms makes it an unnecessary struggle.
What happens if I accidentally use tap water in my starter?
If your starter is solely fed on bottled water, without discarding, feed the starter again with fresh flour and bottled water. This will potentially produce a lot of waste but should save your starter!

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