Water chemistry overview (for better beer) Brewing
Beer is about 90-95 % water so it goes without saying its an important ingredient, however its often overlooked. You can probably brew some specific styles of beer OK with just straight, untreated tap water. However, the truth is, to brew great beer of all styles, you will need to know a little bit about what your water is composed of (in terms of mineral breakdown) and how to make some small changes in order to get it to where you want it to be depending on the style of beer you are brewing. Perhaps you can brew pretty good dark beers, but there’s something not right with your paler beers… chances are the problem lies with your water.
There are many great articles on water for brewing, but most I’ve found to be either far to detailed or not detailed enough in areas and sometimes require you to know data about your water that you just can’t precisely know for whatever reason.
So, the purpose of this article is to scale back a little and run over the absolute basics… what you need to know about your water, how you can get this information yourself, why its important and how you can make some adjustments to get it on target depending on what you want to brew.
Water - the absolute basics
Though we may not realise, water is actually an aggressive solvent, and particularly so if its deionised/distilled (i.e. has little or no absorbed minerals). This means that its capable of, and does, dissolve a variety of different substances that it comes into contact with. In fact, water is referred to as the universal solvent because it dissolves more substances than any other liquid known to man. In practical terms, what this actually means is that as our water makes its way to our local water reservoir and water treatment plant by flowing over various rocks and eventually to our homes, its actually absorbing minerals in the process. So, all natural water contains some level of mineral content which is typically measured in PPM (parts per million). In general, water has a pH of between 6.5 and 8.5, though in practice it is usually pretty close to 7. The pH of water and its resistance to change are important when it comes to the mash in the brewing process which I will cover in the next section.
Why a brewer would alter their water
The mineral content of water can affect various aspects of the brewing process (both positively and negatively) as well as accentuate specific flavours depending on the style of beer.
For brewing and for the purpose of simplicity, we can focus on 3 main aspects of water that we may want to alter.
- Carbonate Hardness/Alkalinity (sometimes listed as CaCO3 in PPM)
- Calcium
- Chlorine (and Chloramine)
Carbonate Hardness/Alkalinity (CaCO3)
CaCO3 (Calcium Carbonate) is generally referred to as temporary hardness or as the alkalinity of water. Alkalinity is defined as follows:
Alkalinity is the capacity of water to resist changes in pH that would make the water more acidic.
The alkalinity of water can also sometimes be referred to its buffering capacity, in other words (as above) its capacity to resist changes in pH.
This is important for a brewer because during the mash, you will want to have a pH of between 5.2 and 5.6 to encourage efficient conversion of starch into fermentable sugar. If water has a pH of, say 7.5, and a relatively high carbonate hardness, you may struggle to hit that number by simply adding your grains without some alterations. A mash with a pH that is higher than 5.5 can lead to the extraction of excess tannins from the grain that lead to a harsh hop bitterness or astringency in the final beer, something which we would prefer to obviously avoid.
Calcium
Calcium is the principal ion that determines hardness (along with magnesium). Calcium is important in the brewing process for the following reasons.
- It interacts with carbonates and can help lower the pH (this is good because we are aiming to get a mash pH of between 5.2 - 5.6 for effective enzyme activity)
- Calcium encourages proteolysis (the breakdown of proteins into smaller polypeptides or amino acids). This means good hot/cold break and a reduction in protein levels in the beer meaning less chill haze/clearer beer.
- Increases beer shelf life via the reduction in pH and also via a reduction in proteins (as above)
- Calcium encourages yeast flocculation during fermentation. (i.e. the clumping together of yeast resulting in it falling out of suspension)
- Calcium protects the enzyme a-amylase from inhibition by heat during the mash by stabilising a-amylase’s temperature to 70 – 75°C. This means it wont fall asleep in the middle of your mash and stop conversion.
There are many more reasons why its an important ion, but I think you get the point… Calcium is important.
Chlorine (and Chloramine)
All public water supplies are generally treated with chlorine or chloramine to kill harmful bugs. These chemicals are used to ensure the water that comes out of your tap wont kill you and, in some cases, they also leave the water with a slight ‘swimming pool’ taste if they are used in high quantities. The problem with these chemicals is that they also have negative affects on some aspects of the brewing process, in particular, at fermentation. During fermentation, yeast produces compounds called ‘phenols’. Where chlorine and chloramine are concerned, yeast eat these compounds and produce ‘chlorophenols’. These phenols have an extremely low taste thresholds. You can taste them even if they exist in only a few parts per billion. A beer that contains even small amounts of this phenol will have a distinctive chemical flavor usually described as plasticy or medicinal. You definitely dont want much of that in your beer, so you might want to consider methods to reduce, or ideally, completely remove these chemicals from your water prior to using it for brewing.
Knowing the numbers in your water supply
Knowing exactly whats in your water can be challenging. You could turn to your local water report which should list the numbers as well as other things in the water, but the slight problem with this is that water values tend to fluctuate quite a bit over the course of the year. Irish water provides this data via their online search page.
In the absence of being able to find the data, I would highly recommend simply buying a relatively cheap testing kit online or in a local aquarium supply store. I use the following two kits and I find them very good.
I highly recommend getting your own test kits as it means you can test your water right before your brew day so you know exactly where you stand. You will also be able to test the water after you have treated it meaning you can validate the treatment you have performed has had the desired effect. Each test is good for between 100 - 200 tests so they will generally last you over 100 brews, so its a worthwhile investment.
How you can get your water on target
For each brewing session, you will generally want your water to align with the style being brewed as each style will require a different water profile. The following table shows a general guide for alkalinity and calcium.
| Style | CaCO3 | Calcium |
|---|---|---|
| Lagers | 25-30 ppm | 40-80 ppm |
| Pale ales/IPAs | 30-50 ppm | 100-220 ppm |
| Amber/Red ales | 100-150 ppm | 90-110 ppm |
| Porters & Stouts | 100-150 ppm | 100-120 ppm |
So, the general rule of thumb is that low alkalinity water is preferred for pale beers and slightly higher alkalinity water is better suited to the darker beers. This is partially due to the fact that the roasted grains used in the brewing of darker beers are more acidic and so help with achieving the desired mash pH even when moderate alkalinity is present in the water.
A basic water treatment for brewing is generally a 3 stage process in this order.
- Chlorine/Chloramine removal
- Adjusting alkalinity to align when style of beer being brewed. This step can impact Calcium levels hence why order is important
- Ensure the right amount of Calcium is present and adjust if necessary using brewing salts.
Step 1: Chlorine/Chloramine removal
Removing chlorine/chloramine thankfully is relatively straightforward. Chlorine is volatile, and will leave your water pretty easily. In fact, simply leaving your water out in an open container over night will mean the majority of chlorine will simply evaporate. Chloramine is a little more difficult to remove without adding something to the water. Thankfully, there is a very cheap and practical solution - Campden tablets. Campden tablets (sodium metabisulfite) can be added to the water at a rate of 1/2 tablet per standard 20 - 25 litre batch. Treating your brewing water with campden tablets will break down Chlorine and Chloramine into Chloride, Sulfate, and Ammonia, all of which tend to be beneficial to beer in small amounts. And a few minutes is all it takes for the break down to be completed.
Step 2: Adjusting alkalinity/CaCO3
There are a couple of ways to adjust water alkalinity. If you need to increase alkalinity, you can simply add Calcium Carbonate/Chalk (CaCO3) or Sodium Bicarbonate/Baking soda (NaHCO3). Since Baking soda is easily obtained, you could use this and a dosage of 0.1g per litre of water which increases the alkalinity by about 60 ppm For me, I never need to increase alkalinity as my water source has a relatively high carbonate hardness (Dublin water), so I nearly always need to reduce it.
The following 2 ways are my preferred ways of getting my alkalinity on target.
Dilution with reverse osmosis/de-ionized/distilled water
Blending your tap water with water that has no carbonate hardness is a simple way to cut the alkalinity back. This has an additional benefit in that it will also cut back any other mineral content that you may not want or care about having in your brewing water. The downside is probably cost. You will need quite a bit of RO/de-ionized/distilled water to make an impact. Roughly speaking, in my experiences, blending half and half will tend to leave you with half the carbonate hardness in the final water give or take a few either side. Simply test after blending to see where the carbonate hardness has landed as its not always so straight forward depending on the ions in you water, so its best to test after blending.
Using Carbonate Reducing Solution (CRS)
CRS is another attractive technique to reduce carbonate hardness. CRS is a blend of food grade hydrochloric and sulphuric acids and is readily available from most homebrew stores. It works by simply acidifying the water using these food grade acids and has little or no affect on flavour in practically all applications I’ve used it in. 1 ml of CRS removes 183 ppm per litre of water, and all the water that is to be used in the brew needs to be treated. The following equation can be used to calculate the amount of CRS needed:
(alkalinity to remove/183) x volume of water
See my practical example for a real world example.
Other techniques
- Boiling water removes carbonate hardness via precipitates of solid calcium carbonate or solid magnesium carbonate but its expensive (in terms of energy needed and time required) and will leave deposits on your elements.
- Lactic acid also reduces alkalinity however can only be used in small amounts due to the fact that it has a lower taste threshold.
- Most homebrew stores sell acid malt which is essentially malt that has been acidified with lactic acid. This can also be used in the mash as part of the grist in small amounts to help adjust the mash pH.
My preferred approach is to either simply use CRS or if I’m brewing something like a pale lager (and sometimes pale ales), I would also tend to blend my water with some RO water first so it cuts back all my numbers and I dont need to use as much CRS.
Step 3: Calcium adjustments
Altering carbonate hardness (e.g. if you are blending water to reduce alkalinity) can also have an impact on calcium levels. So, its important to check the calcium level to ensure there is enough present (ideally using a test kit before treatment). Generally speaking, the minimum amount is 50 ppm but some styles can tolerate larger amounts. Adding Calcium back in can be done in various ways using different types of brewing salts. Any combination is also possible depending on the desired outcome. Some salts also need to be added to the grist rather than to the water, so research the salt you are using before adding.
Gypsum (Calcium Sulphate)
Gypsum can be added to your brewing water at a rate of 0.1g per litre which adds about 23 ppm of calcium. Use at a maximum rate of 0.5g per litre. Using Gypsum also increases the Sulphate rate in your beer and so tends to give a dryer finish and it enhances the perception of bitterness in a highly hopped beer.
Calcium Chloride
Calcium Chloride can be added to your brewing water at a rate of 0.1g per litre which adds about 27 ppm of Calcium. Use at a maximum rate of 0.3g per litre. Using Calcium Chloride also increases the Chloride rate in your beer and tends to be better in a malty beer because it accentuates sweetness and fullness of flavour.
Dry Liquor Salts (DLS)
DLS is a commercial blend of brewing salts (a mix of both Chlorides and Sulphates) designed to increase Calcium levels. DLS used at a rate of 0.1g per litre will add about 17 ppm of Calcium. It is recommended to use DLS in 2 stages.
Stage 1: Of the total brewing water to be used only 1/3 might be for mashing, so add a third to the cold grains before they go into the mash tun.
Stage 2: Add the remainder to the boil kettle at the commencement of the boil.
Using the above guide should allow you to achieve the desired water profile depending on the beer you are brewing.
For a practical guide to this in action, you can see my post on a how I use it when brewing a pale ale.