Brewing Water – Hard or Soft?

by Brad Smith on August 24, 2008 · 29 comments

Brewing water plays a very important role in the flavor of your homebrewed beer. Knowing the character of your local water source as well as how to adjust it to improve your beer is a critical skill, particularly for more advanced brewers.

Water impacts beer in three ways. Water ions are critical in the mashing process for all grain brewers, where the character of the water determines the efficiency and flavor of the extracted wort. Water also affects the perceived bitterness and hop utilization of finished beer. Finally, water adds flavor directly to the beer itself – as water is the largest single component in finished beer.

The effect of brewing water on beer can be characterized by six main water ions: Carbonate, Sodium, Chloride, Sulfate, Calcium and Magnesium.

You can get a water report from your local municipality that will contain the mineral content of your water supply. On a water report you will often see these listed as parts per million (ppm) which is equivalent to one milligram per liter (mg/l). Each of the critical ions is described below:

Carbonate and Bicarbonate (CO3 and HCO3)

Carbonate is considered the most important ion for all grain brewing. Carbonate (or bicarbonate), expressed as “total alkalinity” on many water reports, is the ion that determines the acidity of the mash. It also is the primary determinant in the level of “temporary hardness” of the water. If carbonate levels are too low, the mash will be too acidic, especially when using darker malts (which have higher acidity). If carbonate is too high, mash efficiency will suffer. Recommended levels are 25-50 mg/l for pale beers and 100-300 mg/l for darker beers. Note that bicarbonates and temporary hardness can be reduced by pre-boiling the water – the precipitate that falls out after boiling is primarily bicarbonate.

Sodium (Na)

Sodium contributes body and mouthfeel to the beer, but if used in excess will result in salty seawater flavors. High sodium water often comes from household water softeners, which is why most brewers recommend against mashing with softened water. Sodium levels in the 10-70 mg/l range are normal, and levels of up to 150 mg/l can enhance malty body and fullness, but levels above 200 mg/l are undesirable.

Chloride (Cl)

Chloride, like sodium, also enhances the mouthfeel and complexity of the beer in low concentrations. Chlorine is often used in city water supplies to sanitize, and can also reach high concentrations from use of bleach as a brewing sanitizer. Heavily chlorinated water will result in mediciny or chlorine-like flavors that are undesirable in finished beer. Normal brewing levels should be below 150 mg/l and never exceed 200 mg/l. If you have heavily chlorinated city water you can reduce it using a carbon filter or by pre-boiling the water for 20-30 minutes before use.

Sulfate (SO4)

Sulfate plays a major role in bringing out hop bitterness and adds a dry, sharp, hoppy profile to well hopped beers. It also plays a secondary role to lowering Ph of the mash, but the effect is much less than with carbonates as sulfate is only weakly alkaline. High levels of sulfate will create an astringent profile that is not desirable. Normal levels are 10-50 mg/l for pilsners and light beers and 30-70mg for most ales. Levels from 100-130 mg/l are used in Vienna and Dortmunder styles to enhance bitterness, and Burton on Trent pale ales use concentrations as high as 500 mg/l.

Calcium (Ca)

Calcium is the primary ion determining the “permanent hardness” of the water. Calcium plays multiple roles in the brewing process including lowering the Ph during mashing, aiding in precipitation of proteins during the boil, enhancing beer stability and also acting as an important yeast nutrient. Calcium levels in the 100 mg/l range are highly desirable, and additives should be considered if your water profile has calcium levels below 50 mg/l. The range 50mg/l to 150 mg/l is preferred for brewing.

Magnesium (Mg)

Magnesium is a critical yeast nutrient if used in small amounts. It also behaves as calcium in contributing to water hardness, but this is a secondary role. Levels in the 10-30 mg/l range are desirable, primarily to aid yeast. Levels above 30 mg/l will give a dry, astringent or sour bitter taste to the beer.

You can get a profile of your local water supply from your city or water company. Also, often the local brewing club has already collected local water profiles for you to examine. In the water report, look for the 6 critical items listed above. Also, be aware that many local water suppliers will frequently flush their system periodically (often in the Spring) with highly chlorinated water, which can give you some very strange brewing results if you are unaware of their schedule.

Adjusting your Water

Different styles of beer require different water profiles. Often a particular beer is associated with the water profile of the city in which the beer originated. For a listing of water profiles for popular brewing cities of the world, you can visit our water profile listing. If you have a target profile in mind, you can adjust your water to match that profile.

You can dilute your local tap water with distilled water if some ion counts are too high for your target water profile. Similarly you can use additives to increase the level of key ions. Popular additives include table salt (NaCl), Gypsum (CaSO4), Calcium Chloride (CaCl), Epsom Salts (MgSO4), Baking Soda (NaHCO3), and Chalk (CaCO3).

Unfortunately the additives do not add a straightforward amount of ions to the water profile, so its best to use some kind of water profile tool to adjust your local water supply to reach a target profile. Usually only a few grams of additives is required to achieve your target profile. BeerSmith has a water profile tool available to perform this very function. Other water profile tools are also available online.

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{ 19 comments… read them below or add one }

Cowboy Up January 15, 2009 at 10:29 am

Thanks for the info in your article. I talked to our towns water dept this morning and I could only get a few of the towns water specs as it concerns all grain brewing. The ones that they test for are Calcium/9ppm, Magnesium/1ppm and Sodium/98ppm Hard water is 27. I live in Wyoming, so I,m thinking I may need to use some additives. I haven’t noticed any water problems with extract brewing but I’m not sure I could tell if there was a problem, anything short of a really bad taste or smell which we don’t have. Our water tastes great. If one would use distilled water would you have to add anything to it? From the water profile on Beersmith it shows distilled water void of all the ctitical ions.

Brad Smith January 15, 2009 at 7:34 pm

Hi – Distilled water does not contain any minerals – it is essentially a blank slate and you do need to add some minerals to it. If you are brewing extract and not having any problems with your local water, I would minimize the additives unless you are brewing a special style that needs water additions. Once you move over to all grain, balancing the water and Ph becomes more important. Also if you are brewing styles that need very soft or hard water the additions again become important. Take a look at the style guides and water profiles for their home cities and you will get an idea of what is needed.

Nick Williams January 25, 2010 at 12:37 pm

After using the water profile tool which asks for the brew batch size, the recipe brewsheet adjusts the quantity of salts to be added according to the recipe size. The brewsheet then lists the total quantity of brewing water to be prepared, and the batch size, but calls for the salts to be added to the mash. Is there any need to adjust sparge water ?

Brad Smith January 25, 2010 at 4:34 pm

Nick,
I would say if you add them to the mash water it will be infused into the sparge water as you go. However, I know some brewers who treat the whole batch of water up front and then use that throughout. I’m not sure it makes a huge difference, though treating the mash water itself can result in a better pH in many cases.

rajiv October 16, 2010 at 10:40 pm

is soft water usable for mash water

Brad Smith October 18, 2010 at 2:57 pm

In many cases soft water is quite usable – you need to look at the overall water profile for your local area. I have another article listed here that lists recommended water profile ranges.

Ray August 5, 2011 at 2:25 pm

what about medium-hard water, my (ppm) is about 110 straight from the sink ?

I live in the country, so I use water from my water, I don’t have any chemicals added by the local municipality at all, which I am thinking is a good thing. So far I been doing beer from extracts and it is coming out very good and very tasty, but soon I am going to dive into all grain brews.

Thanks!

Brad Smith August 9, 2011 at 2:47 pm

Ray,
What minerals are in the water is often as important as overall hardness. If possible, get a water report from your local water provider to find out how much of the 6 major ions are in the water.

Brad

Brian October 3, 2011 at 1:57 pm

I usually run all my water through a carbon filter first. Isn’t that going to affect the numbers I get from the city water report? If so, how can I know what my water “looks” like after it’s gone through the filter?

Brad Smith October 3, 2011 at 10:25 pm

Brian,
It will likely affect your water – though how much and how it affects it depends on your filter. Unfortunately I can’t tell you exactly which ions are likely to be trapped by the filter, but perhaps you could ask on the forum where someone with a better chemistry background could help.

Brad

sarat November 18, 2011 at 2:08 am

I wish to know mineral calculation for mashing and brewing. My water which I am using is quite soft water and I am using calcium sulphate and is going good. Now i am thinking to reduce the additive for which i need to calculate ions contents. Kindly suggest.

Dave D September 13, 2012 at 11:03 pm

I use softened water for everything I brew and never had a problem. This may or may not work for everyone else but I find if I use ph stabilizer, I have no problem. I did get the off flavors when I did not use it and also had major extraction issues. If I don’t use it then I average 60% eff. When I do, I get upwards of 80%.

I have been thinking of switching to the potassium chloride pellets but they are way pricier than the sodium equivalent. Even if I do I will stick with the stabilizer. It at least works in my case.

Adam M January 4, 2013 at 11:14 am

Brad,
I contacted my water department and they forwarded the profile to me, which included some of the items you described but others i’m unsure of. The profile is as follows(the values are averages) PH=8.5, P-Alkalinity=4, Total Alk=55, Total hardenss=54, Calcium=46, Magnesium=8, Iron=.018, Chlorides=75. The water plant that serves my area blends RO with Lime Softened water. I’m not sure what I should do for entering values for sodium and sulfate, should I leave blank or assume a value. thanks

Brian Q January 25, 2013 at 6:14 pm

Brad,
When using the water profile tool, next to the base profile there is a space for water volume in gals. Should the value be set to the batch size or the total volume of water used in the mash and sparge additions?

Thanks!

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Patrick August 27, 2013 at 11:26 am

A little bit of misinformation in the Chloride section. Chlorine (a molecule) and Chloride (an ion) are very different. Chloride is naturally occuring in water and does accentuate certain properties in beer. Chlorine is also naturally occuring, but as a gas and not in water. It is quite toxic but used in small quantities to sanitize water. It can (and for brewing purposes, should always be) removed fairly easily with an activated charcoal filter. .

yoeri sanstra September 2, 2013 at 3:45 pm

Hello, the water specification sheet (URL below) from our water company shows the content in MG/L but the profiles are in ppm how can I translate mg/l to ppm?

(https://www.dunea.nl/documents/10156/13625/Katwijk+2e+kw+Waterkwaliteit.pdf/851cfbda-0ad5-451d-a434-e55ea870d7a6?version=1.0)

Brad Smith September 4, 2013 at 9:17 pm

1 mg/l is the same as 1 ppm (they are equivalent!)

Gusty April 9, 2014 at 12:05 am

In Beersmith in the water profile section I see you offer profiles for cities. Do you have a tool that has suggested profiles for brewing specific styles? For example, if I am going to brew an IPA or session IPA, how would I determine the best water profile and then adjust my water to it?

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